One-time application of mixed fertilizer formed by the compounding of two controlled-release nitrogen fertilizers(CRUs)with targeted N supply during the periods from transplantation(TS)to panicle initiation(PI)and fro...One-time application of mixed fertilizer formed by the compounding of two controlled-release nitrogen fertilizers(CRUs)with targeted N supply during the periods from transplantation(TS)to panicle initiation(PI)and from PI to heading(HS)is expected to synchronize the double-peak N demand of rice.However,its effects on the yield and N use efficiency(NUE)of labor-intensive double-cropping rice were unknown.Two targeted CRU(CRU_(A)and CRU_(B))were compounded in five ratios(CRU_(A):CRU_(B)=10:0,7:3,5:5,3:7,and 0:10)to form five mixed fertilizers(BBFs):BBF1-5.A field experiment was performed to investigate the characteristics of N supply in early and late seasons under different BBFs and their effects on N uptake,yield,and ammonia volatilization(AV)loss from paddy fields of double-cropping rice.Conventional high-yield fertilization(CK,three split applications of urea)and zero-N treatments were established as controls.The N supply dropped significantly with the increased compound ratio of CRU_(B)during the period from TS to PI,but increased during the period from PI to HS.With the exception of the period from TS to PI in the late rice season,the N uptake of early and late rice maintained close synchronicity with the N supply of BBFs during the double-peak periods.Excessive N supply(BBF1 and BBF2)in the late rice season during the period from TS to PI increased N loss by AV.The effect of BBF on grain yield increase varied widely between seasons,irrespective of year.Among the BBFs,the BBF2 treatment of early rice not only stabilized the spikelets per panicle but also ensured a high number of effective panicles by promoting N uptake during the period from TS to PI and a high grain-filling percentage by appropriately reducing the N supply at the later PI stage,resulting in the highest rice yield.While stabilizing the effective panicle number,the BBF4 treatment of late rice increased the number of spikelets per panicle by promoting N uptake during the period from PI to HS,resulting in the highest rice yield.The two-year average yield and apparent N recovery efficiency of the BBF2 treatment during the early rice season were 9.6 t ha 1 and 45.3%,while those of late rice in BBF4 were 9.6 t ha 1 and 43.0%,respectively.The yield and NUE indexes of BBF2 in early rice and BBF4 in late rice showed no significant difference from those of CK.The AVs of BBF2 during the early rice season and of BBF4 during the late rice season were 50.0%and 76.8%lower,respectively,than those of CK.BBF2 and BBF4 could effectively replace conventional urea split fertilization in early and late rice seasons,ensuring rice yield and NUE and reducing AV loss in paddy fields.展开更多
Long-term straw return is an important carbon source for improving soil organic carbon(SOC) stocks in croplands, and straw removal through burning is also a common practice in open fields in South China. However, the ...Long-term straw return is an important carbon source for improving soil organic carbon(SOC) stocks in croplands, and straw removal through burning is also a common practice in open fields in South China. However, the specific effects of long-term rice straw management on SOC fractions, the related enzyme activities and their relationships, and whether these effects differ between crop growing seasons remain unknown. Three treatments with equal nitrogen, phosphorus, and potassium nutrient inputs, including straw/ash and chemical nutrients, were established to compare the effects of straw removal(CK), straw return(SR), and straw burned return(SBR). Compared to CK, long-term SR tended to improve the yield of early season rice(P=0.057), and significantly increased total organic carbon(TOC) and microbial biomass carbon(MBC) in double-cropped rice paddies. While SBR had no effect on TOC, it decreased light fraction organic carbon(LFOC) in early rice and easily oxidizable organic carbon(EOC) in late rice, significantly increased dissolved organic carbon(DOC), and significantly decreased soil p H. These results showed that MBC was the most sensitive indicator for assessing changes of SOC in the double-cropped rice system due to long-term straw return. In addition, the different effects on SOC fraction sizes between SR and SBR were attributed to the divergent trends in most of the soil enzyme activities in the early and late rice that mainly altered DOC, while DOC was positively affected by β-xylosidase in both early and late rice. We concluded that straw return was superior to straw burned return for improving SOC fractions, but the negative effects on soil enzyme activities in late rice require further research.展开更多
[Objective] The aim was to research the appropriate seeding quantities of double-season machine-transplanted rice in middle and low-yielding district of southern Jiangxi Province. [Method] The research set five differ...[Objective] The aim was to research the appropriate seeding quantities of double-season machine-transplanted rice in middle and low-yielding district of southern Jiangxi Province. [Method] The research set five different seeding quantities treatments, and compared with conventional seedling treatment, and the appropriate seeding quantities of double season machine-transplanted rice in middle and lowyielding district of southern Jiangxi Province was discussed. [Result] The yields were highest when the seeding quantity was 70 g per tray of early rice by mechanical transplanting and 60 g per tray of late rice. The yield of early rice by mechanical transplanting showed significantly positive correlation with the number of productive ear and the number of seed per ear, and late rice yield showed significant correlation with the number of productive ear by mechanical transplanting. It is key for improving high yields by guaranteeing the number of productive ear. [Conclusion] The issue of proper sowing quantity should be taken into consideration for double-cropping rice in the region, which is crucial for high yields.展开更多
The application of tillering fertilizer plays an important role in promoting rice tillering and improving rice yield. However, under the condition of mechanical transplanting, the optimal application time of tillering...The application of tillering fertilizer plays an important role in promoting rice tillering and improving rice yield. However, under the condition of mechanical transplanting, the optimal application time of tillering fertilizer is still unclear. In this study, the early rice cultivar Zhongjiazao 17 and late rice cultivar H You 518 were used as materials, and the effects of different application times of tillering fertilizer on yield and population development of double-cropping rice transplanted by machine were investigated. The tillering fertilizer was applied 7(D07), 10(D10) and 13(D13) d after the transplanting, respectively. The results showed that compared with those in the D07 treatment groups, the yield of early rice in the D10 and D13 treatment groups were reduced by 9.4% and 3.8%, respectively, and the yield of late rice in the D10 and D13 treatment groups were reduced by 4.5% and 12.6%,respectively. However, there were no significant differences in rice yield among the treatment groups. The application time of tillering fertilizer showed significant effects on grain number per panicle and seed setting rate of early rice. The grain number per panicle in the D10 treatment group was significantly lower than that in the D07 treatment group, and the seed setting rate of the D13 treatment group was significantly lower than that in the D07 treatment group(P〈0.05). For the late rice, the effect of application time of tillering fertilizer on effective tiller number was most obvious, and the effective tiller number in the D13 treatment group was significantly lower than that in the D07 treatment group(P〈0.05). Compared with those in the D07 treatment group, the effective tiller numbers, leaf area indexes and biomasses in the D10 and D13 treatment groups were all trended to be decreased. Therefore,to improve the quality of population and fulfill the high-yielding potential of double-cropping rice transplanted by machine, the tillering fertilizer should be applied as early as possible after rice seedlings turn green.展开更多
ln the research, an empirical analysis was performed on production per-formance and influential factors of rice in Changsha County and Liling City. The re-sults showed that production scale has been closely linked to ...ln the research, an empirical analysis was performed on production per-formance and influential factors of rice in Changsha County and Liling City. The re-sults showed that production scale has been closely linked to age and education level of farmers. The larger scale, the higher comprehensive performance, but rele-vant efficiency tends to be lower. Sowing area and yield per unit area are major in-fluential factors of production performance of double-cropping rice, but the rest influ-ential factors are different upon production scale. Final y, developmental strategies are proposed for development of double-cropping rice.展开更多
Since the early 1980 s, the multi-cropping index for rice has decreased significantly in main double-cropping rice area in China, which is the primary double-cropping rice(DCR) production area. This decline may bring ...Since the early 1980 s, the multi-cropping index for rice has decreased significantly in main double-cropping rice area in China, which is the primary double-cropping rice(DCR) production area. This decline may bring challenges to food security in China because rice is the staple food for more than 60% of the Chinese population. It has been generally recognized that rapidly rising labor costs due to economic growth and urbanization in China is the key driving force of the ‘double-to-single' rice cropping system adaption. However, not all provinces have shown a dramatic decline in DCR area, and labor costs alone cannot explain this difference. To elucidate the reasons for these inter-provincial distinctions and the dynamics of rice cropping system adaption, we evaluated the influencing factors using provincial panel data from 1980 to 2015. We also used household survey data for empirical analysis to explore the mechanisms driving differences in rice multi-cropping changes. Our results indicated that the eight provinces in the study can be divided into three spatial groups based on the extent of DCR area decline, the rapidly-declining marginal, core, and stable zones. Increasing labor cost due to rapid urbanization was the key driving force of rice cropping system adaption, but the land use dynamic vary hugely among different provinces. These differences between zones were due to the interaction between labor price and accumulated temperature conditions. Therefore, increasing labor costs had the greatest impact in Zhejiang, Anhui, and Hubei, where the accumulated temperature is relatively low and rice multi-cropping index declined dramaticly. However, labor costs had little impact in Guangdong and Guangxi. Differences in accumulated temperature conditions resulted in spatially different labor demands and pressure on households during the busy season. As a result, there have been different profits and rice multi-cropping changes between provinces and zones. Because of these spatial differences, regionally appropriate policies that provide appropriate subsidies for early rice in rapidly-declining marginal zone such as Zhejiang and Hubei should be implemented. In addition, agricultural mechanization and the number of agricultural workers have facilitated double-cropping; therefore, small machinery and agricultural infrastructure construction should be further supported.展开更多
In order to explore the technology and effects of reducing nitrogen and potassium fertilizer applications in double-cropping rice,a field plot experiment was conducted to study the effects of optimized application of ...In order to explore the technology and effects of reducing nitrogen and potassium fertilizer applications in double-cropping rice,a field plot experiment was conducted to study the effects of optimized application of nitrogen and potassium fertilizers combined with returning Chinese milk vetch and straw to fields on yield,fertilizer utilization efficiency,net photosynthetic rate(Pn),stomatal conductance(Gs),intercellular CO_(2) concentration(Ci),chlorophyll content(SPAD value)and soil physical and chemical properties in late rice harvest period.The results showed that the optimized application of nitrogen and potassium fertilizers combined with the integrated technology of Chinese milk vetch and straw co-returning to the field could enhance the photosynthetic efficiency of double-cropping rice,increase rice yield,and enhance soil biological activity,especially T4 treatment involving the returning of Chinese milk vetch and straw to the field instead of 30%nitrogen fertilizer achieved the highest rice yield,fertilizer use efficiency,net photosynthetic rate and soil biological activity.Compared with the conventional fertilization treatment T2,the total rice yield of T4 treatment increased by 4.1%,among which the early rice and late rice increased by 6.3%and 2.4%,respectively;Pn,Gs and SPAD values of flag leaves at full heading stage significantly increased,and the contents of soil active organic carbon,alkali hydrolyzed nitrogen,available phosphorus and readily available potassium significantly increased.展开更多
A cDNA clone encoding an ABA-responsiveprotein HVA1,was isolated by differentialscreening from barley aleurone layers(Hong etal.).Expression of the HVA1 gene is shownto be developmentally regulated,organ-specif-ic,and...A cDNA clone encoding an ABA-responsiveprotein HVA1,was isolated by differentialscreening from barley aleurone layers(Hong etal.).Expression of the HVA1 gene is shownto be developmentally regulated,organ-specif-ic,and ABA-and stress-induced(Hong et展开更多
A double-cropping field study was conducted at the Colorado State University, Fruita. Colorado USA to evaluate an irrigated, double-cropping system of winter barley (Hordeum vulgare L.) followed by pinto bean (Phas...A double-cropping field study was conducted at the Colorado State University, Fruita. Colorado USA to evaluate an irrigated, double-cropping system of winter barley (Hordeum vulgare L.) followed by pinto bean (Phaseolus vutgaris L.) for the valley areas of western Colorado USA and other similar environments. Double-cropping pinto bean after winter barley was successful, but to use our double-cropping technology in commercial agriculture in adapted locations will likely require identifying or developing a winter barley cultivar that matures earlier than current cultivars but does not head and flower so early that it is susceptible to freeze damage. Double-cropping was more profitable in all three years than growing either pinto bean or winter barley as a sole crop.展开更多
To explore the high-yield cultivation methods of Zhuliangyou 4024 and H You 159 when planted as double-cropping rice, the effects of two cultivation meth- ods, i.e., seedling broadcasting and transplanting, were studi...To explore the high-yield cultivation methods of Zhuliangyou 4024 and H You 159 when planted as double-cropping rice, the effects of two cultivation meth- ods, i.e., seedling broadcasting and transplanting, were studied on SPAD value, photosynthetic rate, grain yield and yield components. The results showed that the seedling broadcasting cultivation was conducive to Zhuliangyou 4024 and H You 159 to obtain higher yield. The higher chlorophyll content and photosynthetic rate and their slower decrease of flag leaf after full heading of the seedling broadcasting cultivation were thought to be the physiological basis of high yield.展开更多
The research selected 16 rice varieties(8 early and 8 late double-cropping rice) by mechanical transplanting modes as per equivalent row and wide-narrow row to explore yield and physiological traits in order to prov...The research selected 16 rice varieties(8 early and 8 late double-cropping rice) by mechanical transplanting modes as per equivalent row and wide-narrow row to explore yield and physiological traits in order to provide references for selection of rice variety suitable for mechanical transplanting. The results showed that yields of early and late rice improved by 2.90% and 2.73% by mechanical transplanting as per equivalent row and wide-narrow row respectively. Besides, leaf area index in the treatment as per wide-narrow row was higher compared with the treatment as per equivalent row, as well as average photosynthetic potential which grew by 0.92%,3.99% and 5.64% of early from tillering-peak stage to mature stage and 3.46%,7.09% and 6.79% of late rice. Furthermore, by mechanical transplanting as per wide-narrow row, SPAD value, and root activity performer higher, as well as the number of differentiated branch and glumous flowers, but degradation rate showed lower. In addition, with mechanical transplanting the same, early rice Zhuliangyou819 and late rice Fengyuanyou 299 took advantages in yield, which can be priorities for mechanical transplanting in double-cropping areas in Jiangxi Province.展开更多
This study was conducted to reveal the effects of silicon(Si) application on nutrient utilization efficiency by rice and on soil nutrient availability and soil microorganisms in a hybrid rice double-cropping planting ...This study was conducted to reveal the effects of silicon(Si) application on nutrient utilization efficiency by rice and on soil nutrient availability and soil microorganisms in a hybrid rice double-cropping planting system. A series of field experiments were conducted during 2017 and 2018. The results showed that Si nutrient supply improved grain yield and the utilization rates of nitrogen(N) and phosphorus(P) to an appropriate level for both early and late plantings, reaching a maximum at 23.4 kg/ha Si. The same trends were found for the ratios of available N(AN) to total N(TN) and available P(AP) to total P(TP), the soil microbial biomass carbon(MBC), microbial biomass nitrogen(MBN), microbial biomass phosphorus(MBP), and the ratios of MBN to TN and MBP to TP, at different levels of Si. Statistical analysis further revealed that Si application enhanced rice growth and increased the utilization rate of fertilizer due to an ecological mechanism, i.e., Si supply significantly increased the total amount of soil microorganisms in paddy soil compared to the control. This promoted the mineralization of soil nutrients and improved the availability and reserves of easily mineralized organic nutrients.展开更多
Crop phenology retrieval in the double-crop- ping area of China is of great significance in crop yield estimation and water management under the influences of global change. In this study, rice phenology in Jiangsu Pr...Crop phenology retrieval in the double-crop- ping area of China is of great significance in crop yield estimation and water management under the influences of global change. In this study, rice phenology in Jiangsu Province, China was extracted from multi-temporal MODIS NDVI using frequency-based analysis. Pure MODIS pixels of rice were selected with the help of TM images. Discrete Fourier Transformation (DFT), Discrete Wavelet Transformation (DWT), and Empirical Mode Decomposition (EMD) were performed to decompose time series into components of different frequencies. Rice phenology in the double-cropping area is mainly located on the last 2 IMFs of EMD and the first 2-3 frequencies of DFT and DWT. Compared with DFT and DWT, EMD is limited to fewer frequencies. Multi-temporal MODIS NDVI data combined with frequency-based analysis can retrieve rice phenology dates with on average 79% valid estimates. The sorting result for effective estimations from different methods is DWT (85%) 〉 EMD (80%) 〉 DFT (74%). Planting date (88%) is easier to estimate than harvesting date (70%). Rice planting date is easily affected by the former cropping mode within the same year in a double-cropping region. This study sheds light on under- standing crop phenology dynamics in the frequency domain of multi-temporal MODIS data.展开更多
Changes in rice production in Southern China are crucial to national food security.This study employed Landsat images to map the distributions of paddy rice-cropping systems in Southern China in 1990 and 2015.The impa...Changes in rice production in Southern China are crucial to national food security.This study employed Landsat images to map the distributions of paddy rice-cropping systems in Southern China in 1990 and 2015.The impact of rice multiple cropping index changes on grain production capacity was then evaluated.Three important results were obtained for the 1990 to 2015 study period.First,the multiple cropping index for rice decreased from 148.3% to 129.3%,and 253.16×10^4 ha of land area was converted from double-cropping to single- cropping rice,termed “double to single”.The area with the most dramatic changes is in the Middle-Lower Yangtze Plain.The rice-cropping system distribution in Southern China showed a change from north to south with double-cropping rice shrinking and single-cropping rice expanding.Second,the “double to single” conversion led to a reduction of 6.1% and 2.6% in rice and grain production,respectively.Hunan and Jiangxi Provinces,located in the main rice producing areas,and Zhejiang,which has shown better economic development,exhibited large reductions in rice production due to the “double to single” conversion,all exceeding 13%.Third,the grain production capacity of converted “double to single” paddy fields is equivalent to that of 223.3 × 10^4 ha of newly reclaimed cultivated land,which is 54% of the total newly cultivated land reclaimed through the 2001–2015 land consolidation project.It is also 1.7 times the target goal for newly cultivated land in the national land consolidation plan for 2016–2020.Making full use of the converted “double to single” paddy fields can save 167.44 billion yuan in newly reclaimed cultivated land costs.Therefore,instead of pursuing low-quality new arable land,it is better to make full use of the existing high-quality arable land.Based on these results,the government should change the assessment method for cultivated land balance,and incorporate the sown area increased by improving the multiple cropping index into the cultivated land compensation indicator.展开更多
The goal of this study was to map rainfed and irrigated rice-fallow cropland areas across South Asia,using MODIS 250 m time-series data and identify where the farming system may be intensified by the inclusion of a sh...The goal of this study was to map rainfed and irrigated rice-fallow cropland areas across South Asia,using MODIS 250 m time-series data and identify where the farming system may be intensified by the inclusion of a short-season crop during the fallow period.Rice-fallow cropland areas are those areas where rice is grown during the kharif growing season(June–October),followed by a fallow during the rabi season(November–February).These cropland areas are not suitable for growing rabi-season rice due to their high water needs,but are suitable for a short-season(≤3 months),low water-consuming grain legumes such as chickpea(Cicer arietinum L.),black gram,green gram,and lentils.Intensification(double-cropping)in this manner can improve smallholder farmer’s incomes and soil health via rich nitrogen-fixation legume crops as well as address food security challenges of ballooning populations without having to expand croplands.Several grain legumes,primarily chickpea,are increasingly grown across Asia as a source of income for smallholder farmers and at the same time providing rich and cheap source of protein that can improve the nutritional quality of diets in the region.The suitability of rainfed and irrigated rice-fallow croplands for grain legume cultivation across South Asia were defined by these identifiers:(a)rice crop is grown during the primary(kharif)crop growing season or during the north-west monsoon season(June–October);(b)same croplands are left fallow during the second(rabi)season or during the south-east monsoon season(November–February);and(c)ability to support low water-consuming,short-growing season(≤3 months)grain legumes(chickpea,black gram,green gram,and lentils)during rabi season.Existing irrigated or rainfed crops such as rice or wheat that were grown during kharif were not considered suitable for growing during the rabi season,because the moisture/water demand of these crops is too high.The study established cropland classes based on the every 16-day 250 m normalized difference vegetation index(NDVI)time series for one year(June 2010–May 2011)of Moderate Resolution Imaging Spectroradiometer(MODIS)data,using spectral matching techniques(SMTs),and extensive field knowledge.Map accuracy was evaluated based on independent ground survey data as well as compared with available sub-national level statistics.The producers’and users’accuracies of the cropland fallow classes were between 75%and 82%.The overall accuracy and the kappa coefficient estimated for rice classes were 82%and 0.79,respectively.The analysis estimated approximately 22.3 Mha of suitable rice-fallow areas in South Asia,with 88.3%in India,0.5%in Pakistan,1.1%in Sri Lanka,8.7%in Bangladesh,1.4%in Nepal,and 0.02%in Bhutan.Decision-makers can target these areas for sustainable intensification of short-duration grain legumes.展开更多
Due to rapid urbanization and industrialization, many soils for crop production are contaminated by cadmium(Cd), a heavy metal highly toxic to many organisms. Cereal crops such as rice, wheat, maize, and barley are th...Due to rapid urbanization and industrialization, many soils for crop production are contaminated by cadmium(Cd), a heavy metal highly toxic to many organisms. Cereal crops such as rice, wheat, maize, and barley are the primary dietary source of Cd for humans, and reducing Cd transfer from soil to their grains is therefore an important issue for food safety. During the last decade, great progress has been made in elucidating the molecular mechanisms of Cd transport, particularly in rice. Inter-and intraspecific variations in Cd accumulation have been observed in cereal crops. Transporters for Cd have been identified in rice and other cereal crops using genotypic differences in Cd accumulation and mutant approaches. These transporters belong to different transporter families and are involved in the uptake, vacuolar sequestration, root-to-shoot translocation, and distribution of Cd. Attempts have been made to reduce Cd accumulation in grains by manipulating these transporters through overexpression or knockout of the transporter genes, as well as through marker-assisted selection breeding based on genotypic differences in Cd accumulation in the grains. In this review, we describe recent progress on molecular mechanisms of Cd accumulation in cereal crops and compare different molecular strategies for minimizing Cd accumulation in grains.展开更多
In recent years,the abuse of chemical fertilizers has caused numerous environmental problems,such as soil acidification and compaction.Replacing chemical fertilizers with organic fertilizers can effectively alleviate ...In recent years,the abuse of chemical fertilizers has caused numerous environmental problems,such as soil acidification and compaction.Replacing chemical fertilizers with organic fertilizers can effectively alleviate these problems.However,the effects of alternative organic fertilizers remain unclear.To explore the effects of organic fertilizer substitution on rice yield and paddy soil physicochemical properties and bacterial community structure,we conducted a 5-year experiment using different proportions of organic fertilizer substitution in a double-cropping rice field in Jiangxi,China.Our results showed that replacing chemical fertilizers with organic fertilizers can reduce soil acidification,increase soil organic matter content,nutrient contents,and enzyme activities,improve soil physicochemical properties and microbial community,and enhance soil metabolism.Appropriate organic substitution also had positive effects on rice production.These findings enhance our understanding of the effects of different alternative organic fertilization methods and have important theoretical significance for the promotion of the use of organic fertilizers in the future.展开更多
Zinc plays many essential roles in life.As a strong Lewis acid that lacks redox activity under environ-mental and cellular conditions,the Zn2+cation is central in determining protein structure and catalytic function o...Zinc plays many essential roles in life.As a strong Lewis acid that lacks redox activity under environ-mental and cellular conditions,the Zn2+cation is central in determining protein structure and catalytic function of nearly 10%of most eukaryotic proteomes.While specific functions of zinc have been elucidated at a molecular level in a number of plant proteins,wider issues abound with respect to the acquisition and distribution of zinc by plants.An important challenge is to understand how plants balance between Zn supply in soil and their own nutritional requirement for zinc,particularly where edaphic factors lead to a lack of bioavailable zinc or,conversely,an excess of zinc that bears a major risk of phyto-toxicity.Plants are the ultimate source of zinc in the human diet,and human Zn deficiency accounts for over 400000 deaths annually.Here,we review the current understanding of zinc homeostasis in plants from the molecular and physiological perspectives.We provide an overview of approaches pursued so far in Zn biofortification of crops.Finally,we outline a"push-pull"model of zinc nutrition in plants as a simplifying concept.In summary,this review discusses avenues that can potentially deliver wider bene-fits for both plant and human Zn nutrition.展开更多
Modular proteins are an evolutionary answer to optimize performance of proteins that physically interact with each other for functionality. Using a combination of genetic and biochemical experiments, we charac-terized...Modular proteins are an evolutionary answer to optimize performance of proteins that physically interact with each other for functionality. Using a combination of genetic and biochemical experiments, we charac-terized the rice protein OsJAC1, which consists of a jacalin-related lectin (JRL) domain predicted to bind mannose-containing oligosaccharides, and a dirigent domain which might function in stereoselective coupling of monolignols. Transgenic overexpression of OsJAC1 in rice resulted in quantitative broad- spectrum resistance against different pathogens including bacteria, oomycetes, and fungi. Overexpression of this gene or its wheat ortholog TAJA1 in barley enhanced resistance against the powdery mildew fungus. Both protein domains of OsJAC1 are required to establish resistance as indicated by single or combined transient expression of individual domains. Expression of artificially separated and fluorescence-tagged protein domains showed that the JRL domain is sufficient for targeting the powdery mildew penetration site. Nevertheless, co-localization of the lectin and the dirigent domain occurred. Phylogenetic analyses re- vealed orthologs of OsJAC1 exclusively within the Poaceae plant family. Dicots, by contrast, only contain proteins with either JRL or dirigent domain(s). Altogether, our results identify OsJAC1 as a representative of a novel type of resistance protein derived from a plant lineage-specific gene fusion event for better function in local pathogen defense.展开更多
基金provided by the National Key Research and Development Program of China(2018YFD0300904)Anhui Natural Science Foundation(2008085QC119)Key Fund Project of Anhui Department of Education(KJ2019A0176).
文摘One-time application of mixed fertilizer formed by the compounding of two controlled-release nitrogen fertilizers(CRUs)with targeted N supply during the periods from transplantation(TS)to panicle initiation(PI)and from PI to heading(HS)is expected to synchronize the double-peak N demand of rice.However,its effects on the yield and N use efficiency(NUE)of labor-intensive double-cropping rice were unknown.Two targeted CRU(CRU_(A)and CRU_(B))were compounded in five ratios(CRU_(A):CRU_(B)=10:0,7:3,5:5,3:7,and 0:10)to form five mixed fertilizers(BBFs):BBF1-5.A field experiment was performed to investigate the characteristics of N supply in early and late seasons under different BBFs and their effects on N uptake,yield,and ammonia volatilization(AV)loss from paddy fields of double-cropping rice.Conventional high-yield fertilization(CK,three split applications of urea)and zero-N treatments were established as controls.The N supply dropped significantly with the increased compound ratio of CRU_(B)during the period from TS to PI,but increased during the period from PI to HS.With the exception of the period from TS to PI in the late rice season,the N uptake of early and late rice maintained close synchronicity with the N supply of BBFs during the double-peak periods.Excessive N supply(BBF1 and BBF2)in the late rice season during the period from TS to PI increased N loss by AV.The effect of BBF on grain yield increase varied widely between seasons,irrespective of year.Among the BBFs,the BBF2 treatment of early rice not only stabilized the spikelets per panicle but also ensured a high number of effective panicles by promoting N uptake during the period from TS to PI and a high grain-filling percentage by appropriately reducing the N supply at the later PI stage,resulting in the highest rice yield.While stabilizing the effective panicle number,the BBF4 treatment of late rice increased the number of spikelets per panicle by promoting N uptake during the period from PI to HS,resulting in the highest rice yield.The two-year average yield and apparent N recovery efficiency of the BBF2 treatment during the early rice season were 9.6 t ha 1 and 45.3%,while those of late rice in BBF4 were 9.6 t ha 1 and 43.0%,respectively.The yield and NUE indexes of BBF2 in early rice and BBF4 in late rice showed no significant difference from those of CK.The AVs of BBF2 during the early rice season and of BBF4 during the late rice season were 50.0%and 76.8%lower,respectively,than those of CK.BBF2 and BBF4 could effectively replace conventional urea split fertilization in early and late rice seasons,ensuring rice yield and NUE and reducing AV loss in paddy fields.
基金supported by the National Key Research and Development Program of China (2017YFD0301601)the China Postdoctoral Science Foundation (2016M600512)+1 种基金the Open Project Program of State Key Laboratory of Rice Biology, Ministry of Science and Technology, China (20190401)the Jiangxi Province Postdoctoral Research Project Preferential Grant, China (2017KY16)。
文摘Long-term straw return is an important carbon source for improving soil organic carbon(SOC) stocks in croplands, and straw removal through burning is also a common practice in open fields in South China. However, the specific effects of long-term rice straw management on SOC fractions, the related enzyme activities and their relationships, and whether these effects differ between crop growing seasons remain unknown. Three treatments with equal nitrogen, phosphorus, and potassium nutrient inputs, including straw/ash and chemical nutrients, were established to compare the effects of straw removal(CK), straw return(SR), and straw burned return(SBR). Compared to CK, long-term SR tended to improve the yield of early season rice(P=0.057), and significantly increased total organic carbon(TOC) and microbial biomass carbon(MBC) in double-cropped rice paddies. While SBR had no effect on TOC, it decreased light fraction organic carbon(LFOC) in early rice and easily oxidizable organic carbon(EOC) in late rice, significantly increased dissolved organic carbon(DOC), and significantly decreased soil p H. These results showed that MBC was the most sensitive indicator for assessing changes of SOC in the double-cropped rice system due to long-term straw return. In addition, the different effects on SOC fraction sizes between SR and SBR were attributed to the divergent trends in most of the soil enzyme activities in the early and late rice that mainly altered DOC, while DOC was positively affected by β-xylosidase in both early and late rice. We concluded that straw return was superior to straw burned return for improving SOC fractions, but the negative effects on soil enzyme activities in late rice require further research.
基金National Key Technology R&D Program of the Ministry of Science and Technology(2011BAD16B04,(2012BAD04B11)~~
文摘[Objective] The aim was to research the appropriate seeding quantities of double-season machine-transplanted rice in middle and low-yielding district of southern Jiangxi Province. [Method] The research set five different seeding quantities treatments, and compared with conventional seedling treatment, and the appropriate seeding quantities of double season machine-transplanted rice in middle and lowyielding district of southern Jiangxi Province was discussed. [Result] The yields were highest when the seeding quantity was 70 g per tray of early rice by mechanical transplanting and 60 g per tray of late rice. The yield of early rice by mechanical transplanting showed significantly positive correlation with the number of productive ear and the number of seed per ear, and late rice yield showed significant correlation with the number of productive ear by mechanical transplanting. It is key for improving high yields by guaranteeing the number of productive ear. [Conclusion] The issue of proper sowing quantity should be taken into consideration for double-cropping rice in the region, which is crucial for high yields.
基金Supported by Key Project of the National Twelfth-Five Year Research Program of China(2011BAD16B04)"Gan-Po Talent 555"Project of Jiangxi Province[GCZ2012(1)]+2 种基金National Transformation Fund for Agricultural Science and Technology Achievements(2013GB2C500244)Science and Technology Plan of Action for Universities and Colleges in Jiangxi Province(12003)Special Fund for Agro-Scientific Research in the Public Interest(201303102)~~
文摘The application of tillering fertilizer plays an important role in promoting rice tillering and improving rice yield. However, under the condition of mechanical transplanting, the optimal application time of tillering fertilizer is still unclear. In this study, the early rice cultivar Zhongjiazao 17 and late rice cultivar H You 518 were used as materials, and the effects of different application times of tillering fertilizer on yield and population development of double-cropping rice transplanted by machine were investigated. The tillering fertilizer was applied 7(D07), 10(D10) and 13(D13) d after the transplanting, respectively. The results showed that compared with those in the D07 treatment groups, the yield of early rice in the D10 and D13 treatment groups were reduced by 9.4% and 3.8%, respectively, and the yield of late rice in the D10 and D13 treatment groups were reduced by 4.5% and 12.6%,respectively. However, there were no significant differences in rice yield among the treatment groups. The application time of tillering fertilizer showed significant effects on grain number per panicle and seed setting rate of early rice. The grain number per panicle in the D10 treatment group was significantly lower than that in the D07 treatment group, and the seed setting rate of the D13 treatment group was significantly lower than that in the D07 treatment group(P〈0.05). For the late rice, the effect of application time of tillering fertilizer on effective tiller number was most obvious, and the effective tiller number in the D13 treatment group was significantly lower than that in the D07 treatment group(P〈0.05). Compared with those in the D07 treatment group, the effective tiller numbers, leaf area indexes and biomasses in the D10 and D13 treatment groups were all trended to be decreased. Therefore,to improve the quality of population and fulfill the high-yielding potential of double-cropping rice transplanted by machine, the tillering fertilizer should be applied as early as possible after rice seedlings turn green.
基金Supported by Key Financial Program of Hunan Province([2014]74)National Natural Science Foundation of China(41601097)Science&Technology Innovation Project of Hunan Academy of Agriculture Sciences(2016JC08)~~
文摘ln the research, an empirical analysis was performed on production per-formance and influential factors of rice in Changsha County and Liling City. The re-sults showed that production scale has been closely linked to age and education level of farmers. The larger scale, the higher comprehensive performance, but rele-vant efficiency tends to be lower. Sowing area and yield per unit area are major in-fluential factors of production performance of double-cropping rice, but the rest influ-ential factors are different upon production scale. Final y, developmental strategies are proposed for development of double-cropping rice.
基金National Program on Key Basic Research Project(No.2015CB452706)
文摘Since the early 1980 s, the multi-cropping index for rice has decreased significantly in main double-cropping rice area in China, which is the primary double-cropping rice(DCR) production area. This decline may bring challenges to food security in China because rice is the staple food for more than 60% of the Chinese population. It has been generally recognized that rapidly rising labor costs due to economic growth and urbanization in China is the key driving force of the ‘double-to-single' rice cropping system adaption. However, not all provinces have shown a dramatic decline in DCR area, and labor costs alone cannot explain this difference. To elucidate the reasons for these inter-provincial distinctions and the dynamics of rice cropping system adaption, we evaluated the influencing factors using provincial panel data from 1980 to 2015. We also used household survey data for empirical analysis to explore the mechanisms driving differences in rice multi-cropping changes. Our results indicated that the eight provinces in the study can be divided into three spatial groups based on the extent of DCR area decline, the rapidly-declining marginal, core, and stable zones. Increasing labor cost due to rapid urbanization was the key driving force of rice cropping system adaption, but the land use dynamic vary hugely among different provinces. These differences between zones were due to the interaction between labor price and accumulated temperature conditions. Therefore, increasing labor costs had the greatest impact in Zhejiang, Anhui, and Hubei, where the accumulated temperature is relatively low and rice multi-cropping index declined dramaticly. However, labor costs had little impact in Guangdong and Guangxi. Differences in accumulated temperature conditions resulted in spatially different labor demands and pressure on households during the busy season. As a result, there have been different profits and rice multi-cropping changes between provinces and zones. Because of these spatial differences, regionally appropriate policies that provide appropriate subsidies for early rice in rapidly-declining marginal zone such as Zhejiang and Hubei should be implemented. In addition, agricultural mechanization and the number of agricultural workers have facilitated double-cropping; therefore, small machinery and agricultural infrastructure construction should be further supported.
文摘In order to explore the technology and effects of reducing nitrogen and potassium fertilizer applications in double-cropping rice,a field plot experiment was conducted to study the effects of optimized application of nitrogen and potassium fertilizers combined with returning Chinese milk vetch and straw to fields on yield,fertilizer utilization efficiency,net photosynthetic rate(Pn),stomatal conductance(Gs),intercellular CO_(2) concentration(Ci),chlorophyll content(SPAD value)and soil physical and chemical properties in late rice harvest period.The results showed that the optimized application of nitrogen and potassium fertilizers combined with the integrated technology of Chinese milk vetch and straw co-returning to the field could enhance the photosynthetic efficiency of double-cropping rice,increase rice yield,and enhance soil biological activity,especially T4 treatment involving the returning of Chinese milk vetch and straw to the field instead of 30%nitrogen fertilizer achieved the highest rice yield,fertilizer use efficiency,net photosynthetic rate and soil biological activity.Compared with the conventional fertilization treatment T2,the total rice yield of T4 treatment increased by 4.1%,among which the early rice and late rice increased by 6.3%and 2.4%,respectively;Pn,Gs and SPAD values of flag leaves at full heading stage significantly increased,and the contents of soil active organic carbon,alkali hydrolyzed nitrogen,available phosphorus and readily available potassium significantly increased.
文摘A cDNA clone encoding an ABA-responsiveprotein HVA1,was isolated by differentialscreening from barley aleurone layers(Hong etal.).Expression of the HVA1 gene is shownto be developmentally regulated,organ-specif-ic,and ABA-and stress-induced(Hong et
文摘A double-cropping field study was conducted at the Colorado State University, Fruita. Colorado USA to evaluate an irrigated, double-cropping system of winter barley (Hordeum vulgare L.) followed by pinto bean (Phaseolus vutgaris L.) for the valley areas of western Colorado USA and other similar environments. Double-cropping pinto bean after winter barley was successful, but to use our double-cropping technology in commercial agriculture in adapted locations will likely require identifying or developing a winter barley cultivar that matures earlier than current cultivars but does not head and flower so early that it is susceptible to freeze damage. Double-cropping was more profitable in all three years than growing either pinto bean or winter barley as a sole crop.
基金Supported by National Agricultural Science Technology Achievement Transformation Fund(2010GB2D200314)Natural Science Foundation of China(31101134)~~
文摘To explore the high-yield cultivation methods of Zhuliangyou 4024 and H You 159 when planted as double-cropping rice, the effects of two cultivation meth- ods, i.e., seedling broadcasting and transplanting, were studied on SPAD value, photosynthetic rate, grain yield and yield components. The results showed that the seedling broadcasting cultivation was conducive to Zhuliangyou 4024 and H You 159 to obtain higher yield. The higher chlorophyll content and photosynthetic rate and their slower decrease of flag leaf after full heading of the seedling broadcasting cultivation were thought to be the physiological basis of high yield.
基金Supported by National"Twelfth Five-Year"Plan for Science&Technology Support(2011BAD16B04)Super High-yielding Rice and"555"Talent Leading Program of Jiangxi Province~~
文摘The research selected 16 rice varieties(8 early and 8 late double-cropping rice) by mechanical transplanting modes as per equivalent row and wide-narrow row to explore yield and physiological traits in order to provide references for selection of rice variety suitable for mechanical transplanting. The results showed that yields of early and late rice improved by 2.90% and 2.73% by mechanical transplanting as per equivalent row and wide-narrow row respectively. Besides, leaf area index in the treatment as per wide-narrow row was higher compared with the treatment as per equivalent row, as well as average photosynthetic potential which grew by 0.92%,3.99% and 5.64% of early from tillering-peak stage to mature stage and 3.46%,7.09% and 6.79% of late rice. Furthermore, by mechanical transplanting as per wide-narrow row, SPAD value, and root activity performer higher, as well as the number of differentiated branch and glumous flowers, but degradation rate showed lower. In addition, with mechanical transplanting the same, early rice Zhuliangyou819 and late rice Fengyuanyou 299 took advantages in yield, which can be priorities for mechanical transplanting in double-cropping areas in Jiangxi Province.
基金Project supported by the National Key Research and Development Project of China(No.2016YFD0200800)the National Natural Science foundation of China(No.41571226)。
文摘This study was conducted to reveal the effects of silicon(Si) application on nutrient utilization efficiency by rice and on soil nutrient availability and soil microorganisms in a hybrid rice double-cropping planting system. A series of field experiments were conducted during 2017 and 2018. The results showed that Si nutrient supply improved grain yield and the utilization rates of nitrogen(N) and phosphorus(P) to an appropriate level for both early and late plantings, reaching a maximum at 23.4 kg/ha Si. The same trends were found for the ratios of available N(AN) to total N(TN) and available P(AP) to total P(TP), the soil microbial biomass carbon(MBC), microbial biomass nitrogen(MBN), microbial biomass phosphorus(MBP), and the ratios of MBN to TN and MBP to TP, at different levels of Si. Statistical analysis further revealed that Si application enhanced rice growth and increased the utilization rate of fertilizer due to an ecological mechanism, i.e., Si supply significantly increased the total amount of soil microorganisms in paddy soil compared to the control. This promoted the mineralization of soil nutrients and improved the availability and reserves of easily mineralized organic nutrients.
文摘Crop phenology retrieval in the double-crop- ping area of China is of great significance in crop yield estimation and water management under the influences of global change. In this study, rice phenology in Jiangsu Province, China was extracted from multi-temporal MODIS NDVI using frequency-based analysis. Pure MODIS pixels of rice were selected with the help of TM images. Discrete Fourier Transformation (DFT), Discrete Wavelet Transformation (DWT), and Empirical Mode Decomposition (EMD) were performed to decompose time series into components of different frequencies. Rice phenology in the double-cropping area is mainly located on the last 2 IMFs of EMD and the first 2-3 frequencies of DFT and DWT. Compared with DFT and DWT, EMD is limited to fewer frequencies. Multi-temporal MODIS NDVI data combined with frequency-based analysis can retrieve rice phenology dates with on average 79% valid estimates. The sorting result for effective estimations from different methods is DWT (85%) 〉 EMD (80%) 〉 DFT (74%). Planting date (88%) is easier to estimate than harvesting date (70%). Rice planting date is easily affected by the former cropping mode within the same year in a double-cropping region. This study sheds light on under- standing crop phenology dynamics in the frequency domain of multi-temporal MODIS data.
基金National Natural Science Foundation of China,No.41571095,No.41161140352
文摘Changes in rice production in Southern China are crucial to national food security.This study employed Landsat images to map the distributions of paddy rice-cropping systems in Southern China in 1990 and 2015.The impact of rice multiple cropping index changes on grain production capacity was then evaluated.Three important results were obtained for the 1990 to 2015 study period.First,the multiple cropping index for rice decreased from 148.3% to 129.3%,and 253.16×10^4 ha of land area was converted from double-cropping to single- cropping rice,termed “double to single”.The area with the most dramatic changes is in the Middle-Lower Yangtze Plain.The rice-cropping system distribution in Southern China showed a change from north to south with double-cropping rice shrinking and single-cropping rice expanding.Second,the “double to single” conversion led to a reduction of 6.1% and 2.6% in rice and grain production,respectively.Hunan and Jiangxi Provinces,located in the main rice producing areas,and Zhejiang,which has shown better economic development,exhibited large reductions in rice production due to the “double to single” conversion,all exceeding 13%.Third,the grain production capacity of converted “double to single” paddy fields is equivalent to that of 223.3 × 10^4 ha of newly reclaimed cultivated land,which is 54% of the total newly cultivated land reclaimed through the 2001–2015 land consolidation project.It is also 1.7 times the target goal for newly cultivated land in the national land consolidation plan for 2016–2020.Making full use of the converted “double to single” paddy fields can save 167.44 billion yuan in newly reclaimed cultivated land costs.Therefore,instead of pursuing low-quality new arable land,it is better to make full use of the existing high-quality arable land.Based on these results,the government should change the assessment method for cultivated land balance,and incorporate the sown area increased by improving the multiple cropping index into the cultivated land compensation indicator.
基金supported by two CGIAR Research Programs:Dryland Cereals,Grain legumes and WLE.The research was also supported by the global food security support analysis data at 30 m project(GFSAD30http://geography.wr.usgs.gov/science/croplands/https://croplands.org/)funded by the NASA MEaSUREs[grant number:NNH13AV82I](Making Earth System Data Records for Use in Research Environments)funding obtained through NASA ROSES solicitation as well as by the Land Change Science(LCS),Land Remote Sensing(LRS),and Climate Land Use Change Mission Area Programs of the U.S.Geological Survey(USGS).
文摘The goal of this study was to map rainfed and irrigated rice-fallow cropland areas across South Asia,using MODIS 250 m time-series data and identify where the farming system may be intensified by the inclusion of a short-season crop during the fallow period.Rice-fallow cropland areas are those areas where rice is grown during the kharif growing season(June–October),followed by a fallow during the rabi season(November–February).These cropland areas are not suitable for growing rabi-season rice due to their high water needs,but are suitable for a short-season(≤3 months),low water-consuming grain legumes such as chickpea(Cicer arietinum L.),black gram,green gram,and lentils.Intensification(double-cropping)in this manner can improve smallholder farmer’s incomes and soil health via rich nitrogen-fixation legume crops as well as address food security challenges of ballooning populations without having to expand croplands.Several grain legumes,primarily chickpea,are increasingly grown across Asia as a source of income for smallholder farmers and at the same time providing rich and cheap source of protein that can improve the nutritional quality of diets in the region.The suitability of rainfed and irrigated rice-fallow croplands for grain legume cultivation across South Asia were defined by these identifiers:(a)rice crop is grown during the primary(kharif)crop growing season or during the north-west monsoon season(June–October);(b)same croplands are left fallow during the second(rabi)season or during the south-east monsoon season(November–February);and(c)ability to support low water-consuming,short-growing season(≤3 months)grain legumes(chickpea,black gram,green gram,and lentils)during rabi season.Existing irrigated or rainfed crops such as rice or wheat that were grown during kharif were not considered suitable for growing during the rabi season,because the moisture/water demand of these crops is too high.The study established cropland classes based on the every 16-day 250 m normalized difference vegetation index(NDVI)time series for one year(June 2010–May 2011)of Moderate Resolution Imaging Spectroradiometer(MODIS)data,using spectral matching techniques(SMTs),and extensive field knowledge.Map accuracy was evaluated based on independent ground survey data as well as compared with available sub-national level statistics.The producers’and users’accuracies of the cropland fallow classes were between 75%and 82%.The overall accuracy and the kappa coefficient estimated for rice classes were 82%and 0.79,respectively.The analysis estimated approximately 22.3 Mha of suitable rice-fallow areas in South Asia,with 88.3%in India,0.5%in Pakistan,1.1%in Sri Lanka,8.7%in Bangladesh,1.4%in Nepal,and 0.02%in Bhutan.Decision-makers can target these areas for sustainable intensification of short-duration grain legumes.
基金supported by the Grant-in-Aid for Specially Promoted Research, Japan (JSPS KAKENHI Grant No. 16H06296 to J. F. Ma.)the grants from the Scientific Research Development Foundation of Zhejiang A&F University for the Talents, China (No. 2019FR002)the Major Special Science and Technology Project of Zhejiang Province, China (No. 2016C02G2101016)。
文摘Due to rapid urbanization and industrialization, many soils for crop production are contaminated by cadmium(Cd), a heavy metal highly toxic to many organisms. Cereal crops such as rice, wheat, maize, and barley are the primary dietary source of Cd for humans, and reducing Cd transfer from soil to their grains is therefore an important issue for food safety. During the last decade, great progress has been made in elucidating the molecular mechanisms of Cd transport, particularly in rice. Inter-and intraspecific variations in Cd accumulation have been observed in cereal crops. Transporters for Cd have been identified in rice and other cereal crops using genotypic differences in Cd accumulation and mutant approaches. These transporters belong to different transporter families and are involved in the uptake, vacuolar sequestration, root-to-shoot translocation, and distribution of Cd. Attempts have been made to reduce Cd accumulation in grains by manipulating these transporters through overexpression or knockout of the transporter genes, as well as through marker-assisted selection breeding based on genotypic differences in Cd accumulation in the grains. In this review, we describe recent progress on molecular mechanisms of Cd accumulation in cereal crops and compare different molecular strategies for minimizing Cd accumulation in grains.
基金supported by the National Key R&D Program of China(Nos.2017YFD0301601 and 2016YFD-0200402)National Natural Science Foundation of China(No.31560582)+1 种基金Beijing Key Laboratory of Biodiversity and Organic Farming,China(No.BOF201902)the funds of the Shandong"Double Tops"Program,China.
文摘In recent years,the abuse of chemical fertilizers has caused numerous environmental problems,such as soil acidification and compaction.Replacing chemical fertilizers with organic fertilizers can effectively alleviate these problems.However,the effects of alternative organic fertilizers remain unclear.To explore the effects of organic fertilizer substitution on rice yield and paddy soil physicochemical properties and bacterial community structure,we conducted a 5-year experiment using different proportions of organic fertilizer substitution in a double-cropping rice field in Jiangxi,China.Our results showed that replacing chemical fertilizers with organic fertilizers can reduce soil acidification,increase soil organic matter content,nutrient contents,and enzyme activities,improve soil physicochemical properties and microbial community,and enhance soil metabolism.Appropriate organic substitution also had positive effects on rice production.These findings enhance our understanding of the effects of different alternative organic fertilization methods and have important theoretical significance for the promotion of the use of organic fertilizers in the future.
文摘Zinc plays many essential roles in life.As a strong Lewis acid that lacks redox activity under environ-mental and cellular conditions,the Zn2+cation is central in determining protein structure and catalytic function of nearly 10%of most eukaryotic proteomes.While specific functions of zinc have been elucidated at a molecular level in a number of plant proteins,wider issues abound with respect to the acquisition and distribution of zinc by plants.An important challenge is to understand how plants balance between Zn supply in soil and their own nutritional requirement for zinc,particularly where edaphic factors lead to a lack of bioavailable zinc or,conversely,an excess of zinc that bears a major risk of phyto-toxicity.Plants are the ultimate source of zinc in the human diet,and human Zn deficiency accounts for over 400000 deaths annually.Here,we review the current understanding of zinc homeostasis in plants from the molecular and physiological perspectives.We provide an overview of approaches pursued so far in Zn biofortification of crops.Finally,we outline a"push-pull"model of zinc nutrition in plants as a simplifying concept.In summary,this review discusses avenues that can potentially deliver wider bene-fits for both plant and human Zn nutrition.
文摘Modular proteins are an evolutionary answer to optimize performance of proteins that physically interact with each other for functionality. Using a combination of genetic and biochemical experiments, we charac-terized the rice protein OsJAC1, which consists of a jacalin-related lectin (JRL) domain predicted to bind mannose-containing oligosaccharides, and a dirigent domain which might function in stereoselective coupling of monolignols. Transgenic overexpression of OsJAC1 in rice resulted in quantitative broad- spectrum resistance against different pathogens including bacteria, oomycetes, and fungi. Overexpression of this gene or its wheat ortholog TAJA1 in barley enhanced resistance against the powdery mildew fungus. Both protein domains of OsJAC1 are required to establish resistance as indicated by single or combined transient expression of individual domains. Expression of artificially separated and fluorescence-tagged protein domains showed that the JRL domain is sufficient for targeting the powdery mildew penetration site. Nevertheless, co-localization of the lectin and the dirigent domain occurred. Phylogenetic analyses re- vealed orthologs of OsJAC1 exclusively within the Poaceae plant family. Dicots, by contrast, only contain proteins with either JRL or dirigent domain(s). Altogether, our results identify OsJAC1 as a representative of a novel type of resistance protein derived from a plant lineage-specific gene fusion event for better function in local pathogen defense.