Drought is a main abiotic stress factor hindering plant growth,development,and crop productivity.Therefore,it is crucial to understand the mechanisms by which plants cope with drought stress.Here,the function of the m...Drought is a main abiotic stress factor hindering plant growth,development,and crop productivity.Therefore,it is crucial to understand the mechanisms by which plants cope with drought stress.Here,the function of the maize peroxidase gene ZmPRX1 in drought stress tolerance was investigated by measurement of its expression in response to drought treatment both in a ZmPRX1 overexpression line and a mutant line.The higher root lignin accumulation and seedling survival rate of the overexpression line than that of the wild type or mutant support a role for ZmPRX1 in maize drought tolerance by regulating root development and lignification.Additionally,yeast one-hybrid,Dule luciferase and ChIP-qPCR assays showed that ZmPRX1 is negatively regulated by a nuclear-localized ZmWRKY86 transcription factor.The gene could potentially be used for breeding of drought-tolerant cultivars.展开更多
Maize(Zea mays L.)is a global cereal crop whose demand is projected to double by 2050.Along with worsening of farmland salinization,salt stress has become a major environmental threat to the sustainability of maize pr...Maize(Zea mays L.)is a global cereal crop whose demand is projected to double by 2050.Along with worsening of farmland salinization,salt stress has become a major environmental threat to the sustainability of maize production worldwide.Accordingly,there is an urgent need to decipher salt-tolerant mechanisms and facilitate the breeding of salt-tolerant maize.As salt tolerance is a complex trait regulated by multiple genes,and maize germplasm varies widely in salt tolerance,efforts have been devoted to the identification and application of quantitative-trait loci(QTL)for salt tolerance.QTL associated with ion regulation,osmotic tolerance,and other aspects of salt tolerance have been discovered using genomewide association studies(GWAS),linkage mapping,and omics-based approaches.This review highlights recent advances in the molecular-level understanding of salt stress response in maize,in particular in(a)the discovery of salt-tolerance QTL,(b)the mechanisms of salt tolerance,(c)the development of salttolerant maize cultivars,and(d)current challenges and future prospects.展开更多
Maize is an important food crop, as well as the irreplaceable feed and industrial materials, having huge market demand in China. Southwestern region of China is the third largest main maize producing zone, and the fre...Maize is an important food crop, as well as the irreplaceable feed and industrial materials, having huge market demand in China. Southwestern region of China is the third largest main maize producing zone, and the frequent occurrence of abiotic stress conditions such as drought, heat, cold, wet shaded stress have severely affected the development of maize production, causing low and unstable corn yields, severely restricting the maize industry development in the southwest of China. This paper preliminarily describes the maize resistance to abiotic stresses in southwestem region of China, putting forward the countermeasures and the key research direction in the practice of breeding in order to provide reference for the cultivation of new varieties with high yield and stress resistance, and improving the levels of maize stress resistance breeding in southwestern region of China.展开更多
By using complete-diallel cross design(Griffing method I), the influence of the combination of different high-yield genotypes of maize on the drought tolerance of their offspring, the general combining ability, the ...By using complete-diallel cross design(Griffing method I), the influence of the combination of different high-yield genotypes of maize on the drought tolerance of their offspring, the general combining ability, the specific combining ability and the back cross effect of drought tolerance between parents and the main genetic parameters for drought tolerance were analyzed. The result indicated that there were significant differences in general combining ability effects(GCA) of maize; there were highly significant differences in special combining ability effects(SCA); there was no significant difference in reciprocal effects(R). There were apparent differences in drought tolerance among six parents; to be specific, Zheng 58 had the highest drought tolerance, while PH4CV had the lowest. Improving drought-tolerant parents with Zheng 58, Ji 853 and Xinzi 8717 had gain superiority effects on the increase of drought tolerance in offspring. The influence of the genetic additive effect on the drought tolerance of offsprings varied with different parents and combinations. Therefore, the expression of drought tolerance inheritance genes was determined only by the additive and non-additive genetic effects but had little relationship with reciprocal effects. The selection of drought tolerance of maize should be conducted at higher generations.展开更多
Waterlogging strongly affects agronomic performance of maize (Zea mays L.). In order to investigate the suitable selection criteria of waterflooding tolerant genotypes, and identify the most susceptible stage and th...Waterlogging strongly affects agronomic performance of maize (Zea mays L.). In order to investigate the suitable selection criteria of waterflooding tolerant genotypes, and identify the most susceptible stage and the best continuous treatment time to waterlogging, 20 common maize inbred lines were subjected to successive artificial waterflooding at seedling stage, and waterlogging tolerance coefficient (WTC) was used to screen waterflooding tolerant genotypes. In addition, peroxidase (POD) activities and malondialdehyde (MDA) contents were measured for 6 of 20 lines. The results showed that the second leaf stage (V2) was the most susceptible stage, and 6 d after waterflooding was the best continuous treatment time. Dry weight (DW) of both shoots and roots of all lines were significantly reduced at 6 d time-point of waterlogging, compared to control. POD activities and MDA contents were negatively and significantly correlated, and the correlation coefficient was -0.9686 (P 〈 0.0001). According to the results, WTC of shoot DW can be used for practical screening as a suitable index, which is significantly different from control and waterlogged plants happened 6 d earlier. Furthermore, leaf chlorosis, MDA content and POD activities could also be used as reference index for material screening. The implications of the results for waterlogging-tolerant material screening and waterlogging-tolerant breeding have been discussed in maize.展开更多
Drought is a major constraint in maize production worldwide. We studied quantitative trait loci (QTL) underlying drought tolerance for maize plants grown in two different environments. Traits investigated included A...Drought is a major constraint in maize production worldwide. We studied quantitative trait loci (QTL) underlying drought tolerance for maize plants grown in two different environments. Traits investigated included ASI, plant height, grain yield, ear height, and ear setting. A genetic linkage map was constructed with 120 simple sequence repeat (SSR) markers based on an F2 population derived from a cross between D5 (resistant parent) and 7924 (susceptible parent). Correlation and heritability were calculated. QTLs of these traits were identified by composite interval mapping combined with a linkage map covering 1 790.3 cM. The markers were arranged in ten linkage groups. QTL mapping was made of the mean trait performance of the 180 F2:3 population. The results showed five, five, six, four, and five QTLs for ASI, plant height, grain yield, ear height, and ear setting under full irrigation condition, respectively, and four, seven, six, four, and four QTLs for ASI, plant height, grain yield, ear height, and ear setting under severe late stress conditions, respectively. Especially the four QTLs detected for five traits in 2008 and 2009. The universal QTLs information generated in this study will aid in undertaking an integrated breeding strategy for further genetic studies in drought tolerance improvement in maize.展开更多
Phosphorus nutrient characteristics of different maize inbred lines to low-P stress were studied at stages of seedling, steming, earing, silking under pot culture. In the periods of seedling and steming, P uptake effi...Phosphorus nutrient characteristics of different maize inbred lines to low-P stress were studied at stages of seedling, steming, earing, silking under pot culture. In the periods of seedling and steming, P uptake efficiency was the main contributor to P tolerance, and the relative P content in P-tolerant genotypes, 99180 and 99239 were higher than that in sensitive genotype, 99152. At earing stage, P-tolerant genotypes, compared to P-sensitive ones, had higher accumulation of P in upper leaves. When came to the silking stage, P uptake and redistribution efficiency of P-tolerant genotypes were higher than those in 99152. The results also suggested that there are different mechanisms of P nutrient uptake and distribution in different P-tolerant genotypes. Inbred line 99239, according to the investigation, was considered as an efficient stock in the P-uptake while 99180 fallen to the efficient stock of P redistribution.展开更多
It has previously been shown that a bacterial 5-enolpyruvylshikimate-3-phosphate synthase(EPSPS) encoding gene AM79 aroA can be a candidate gene to develop glyphosate-tolerant transgenic crops(Cao et al. 2012). In...It has previously been shown that a bacterial 5-enolpyruvylshikimate-3-phosphate synthase(EPSPS) encoding gene AM79 aroA can be a candidate gene to develop glyphosate-tolerant transgenic crops(Cao et al. 2012). In this study, AM79 aroA was redesigned using the plant biased codons and eliminating the motifs which would lead to the instability of mRNA, to create a synthetic gene that would be expressed highly in plant cells. The redesigned and artificially synthesized gene, named as mAM79, was cloned into plant expression vector pM3301 Ubi Sp AM79, where mAM79 is fused with signal peptide sequence of pea rib-1,5-bisphospate carboxylase(rbcS) small subunit and controlled by ubiquitin promoter. The plasmid was transformed into maize(Zea mays) immature embryos using Agrobacterium-mediated transformation method. Total 74 regenerated plants were obtained and PCR analysis showed that these transgenic plants had the integration of mAM79. Southern blot analysis was performed on the genomic DNA from four transgenic lines, and the result showed that one or two copies of mAM79 were integrated into maize genome. RT-PCR analysis result indicated that mAM79 was highly transcribed in transgenic maize plants. When sprayed with glyphosate, transgenic maize line AM85 and AM72 could tolerate 4-fold of commercial usage of glyphosate; however, all the non-transgenic maize plants were killed by glyphosate. The results in this study confirmed that mAM79 could be used to develop glyphosate-tolerant maize, and the obtained transgenic maize lines could be used for the breeding of glyphosate-tolerant maize.展开更多
Maize growth and development is affected by low temperature(LT) especially at the early stages of development. To describe the response of different varieties to LT stress and determine an effective method to cope wit...Maize growth and development is affected by low temperature(LT) especially at the early stages of development. To describe the response of different varieties to LT stress and determine an effective method to cope with LT stress, maize hybrids Zhengdan 958(ZD 958) and Danyu 39(DY 39) were planted and grown at 10 and 25°C, respectively. Effects of the chemicals potassium chloride(KCl), gibberellin(GA), 2-diethylaminoethyl-3,4-dichlorophenylether(DCPTA), and all three combined chemicals(KGD) on coping with LT stress were tested by seed priming. The varieties performed significantly different at 10°C. Compared to leaf, root growth was more severely affected by LT stress. Root/leaf ratio is likely a more reliable parameter to evaluate cold tolerance based on its close correlation with leaf malondialdehyde(MDA) content(R=–0.8). GAadvanced seed germination by about 2 days compared with control treatment of water. GAand DCPTA both resulted in lower leaf MDA content and higher leaf and root area, and root/leaf ratio. KCl resulted in the highest evenness of plant height. KGD performed the best in increasing cold tolerance of maize morphologically and physiologically. Strategies to increase maize tolerance of cold stress, such as variety breeding or chemical selection, would increase maize yield especially at high-latitude regions and have great implications for food security.展开更多
Using linker peptide LP4/2A for multiple gene transformation is considered to be an effective method to stack or pyramid several traits in plants. Bacillus thuringiensis(Bt) cry gene and epsps(5-enolpyruvylshikimat...Using linker peptide LP4/2A for multiple gene transformation is considered to be an effective method to stack or pyramid several traits in plants. Bacillus thuringiensis(Bt) cry gene and epsps(5-enolpyruvylshikimate-3-phosphate synthase) gene are two important genes for culturing pest-resistant and glyphosate-tolerant crops. We used linker peptide LP4/2A to connect the Bt cry1 Ah gene with the 2m G2-epsps gene and combined the wide-used man A gene as a selective marker to construct one coordinated expression vector called p2 EPUHLAGN. The expression vector was transferred into maize by Agrobacterium tumefaciens-mediated transformation, and 60 plants were obtained, 40% of which were positive transformants. Molecular detection demonstrated that the two genes in the fusion vector were expressed simultaneously and spliced correctly in translation processing; meanwhile bioassay detection proved the transgenic maize had preferable pest resistance and glyphosate tolerance. Therefore, linker peptide LP4/2A provided a simple and reliable strategy for producing gene stacking in maize and the result showed that the fusion gene transformation system of LP4/2A was feasible in monocot plants.展开更多
Thirteen different inbred lines in relation to the type of grain and life cycles were characterized by testing for osmotic stress associated with salinity. The identification of tolerant genotypes would be an effectiv...Thirteen different inbred lines in relation to the type of grain and life cycles were characterized by testing for osmotic stress associated with salinity. The identification of tolerant genotypes would be an effective strategy to overcome the saline stress. Osmotic stress reduces immediately the expansion of the roots and young leaves which determine a reduction in the size of the plant. A completely randomized design was adopted to test seedlings under controlled conditions of light and temperature. Two treatments were used: 0 mM NaCl (as control) and 100 mM NaCl. After 15 days of complete salinization, the seedlings were harvested and several morphological traits were measured. The morphological traits of growth were leaf growth (Ar1, Ar2, Ar3 and Ar4), dry masses of shoot and root (SDM and RDM, respectively). Also, traits associated with water economy were registered: leaf water loss (LWL) and relative water content (RWC). The morphological traits were expressed in relative terms, while the traits associated with the economy of water were expressed in absolute terms. Uni and multivariate techniques were applied to identify genotypes with divergent behaviors to osmotic stress tolerance. Also, a Tolerance Index was employed to identify superior genotypes. Four clusters were obtained after applying a Cluster Analysis and Principal Component Analysis (PCA). The genotypes were compared to each other with a test of DMS. The results obtained with different statistical techniques converged. Some variables presented a differential weight classification of genotypes. The morphological traits like RDM, SDM, Ar3, Ar4 and Ar5 were the most discriminating. Tolerance Index allowed to classify genotypes, thus SC2 and AD3 lines were that reached highest value of the index and therefore would be tolerant lines, while AF3 and LP3 had a low index and were seen as sensible.展开更多
Six tropical maize inbred lines were crossed in a half diallel fashion and evaluated along with their F1 hybrids under low N (0 kg/ha) and high N(170 kg/ha), for grain yield, ear diameter, ear length, number of rows p...Six tropical maize inbred lines were crossed in a half diallel fashion and evaluated along with their F1 hybrids under low N (0 kg/ha) and high N(170 kg/ha), for grain yield, ear diameter, ear length, number of rows per ear, 100-kernel weight, ear leaf area, shoot dry weight, ear leaf chlorophyll content and plant height to determine their response to different level of N. Grain yield and ear leaf chlorophyll content measured by 48% lower under -N than under + N, and were most affected by -N. Ear length had the highest reduction under -N of 22%. Plant height and shoot dry weight were both reduced by 28%. Diallel analysis indicated significant additive as well as dominance variance for grain yield under -N. The same results were shown when one tolerant x nontolerant cross from the diallel hybrids was subjected to generation mean analysis which also indicated significant epistatic effects. These results suggest that S1 or S2 progeny selection may be an effective means of improving grain yield of tropical maize under low soil N.展开更多
[ Objective] This study aimed to map quantitative tarit loci (QTLs) associated with salt tolerance of maize inbred line at seedling stage. [ Method! The recombinant inbred line (RIL) F7 including 171 plants were d...[ Objective] This study aimed to map quantitative tarit loci (QTLs) associated with salt tolerance of maize inbred line at seedling stage. [ Method! The recombinant inbred line (RIL) F7 including 171 plants were developed by single seed descent procedure from a combination, Huangzazsi × Mo17, and used to map QTLs associated with salt tolerance, based on the constructed genetic map of SSR markers. [ Resultl A linkage map consisting of 81 SSR markers loci from 10 chromosomes ( 1 428.3 cM in total length, with an average distance of 17.63 cM between two neighbouring loci) was constructed. Six QTI~ associated significantly with salt tolerance were detected at chromosomes 1,5 and 6. [ Conclusion] This study is extremely significant for better understanding sah tolerance-related genes, the genes' location and cloning, salt tolerance mechanism and the marker-assisted selection of salt tolerant maize.展开更多
Total 20 maize varieties were subjected to drought stress at flowering stage,and then the relative water content,soluble sugar content,chlorophyll content,malondialdehyde( MDA) content and superoxide dismutase( SOD) a...Total 20 maize varieties were subjected to drought stress at flowering stage,and then the relative water content,soluble sugar content,chlorophyll content,malondialdehyde( MDA) content and superoxide dismutase( SOD) activity in their leaves,as well as their yields were determined. The drought tolerance of the physiological and biochemical indexes was scored by five-level scoring method,and the drought tolerance index was calculated by the yield index to comprehensively evaluate the drought tolerance of maize during flowering stage. The results showed that the scores of drought tolerance of the maize varieties ranged from 1. 929 3 to 5. 659 5. Among them,the scores of Zhengda 619,Guidan 162 and Guidan 0810 were greater than 5. 0,followed by Dika 008,Xianyu 30 T60,Xianzhengda 901,Qingnong 68,South America No. 1 and Wanchuan 1306 of which the scores were in the range of 4. 0-5. 0. The drought tolerance indexes were in the range of 0. 410 4-1. 096 3. Among the test maize varieties,the drought tolerance indexes of Guidan 0810,Pacific 99 and Zhengda 619 were greater than 1. 0,and those of Xianyu 30 T60,Dika 008 and South America No. 1 were in the range of 0. 9-1. 0. The correlation between the two kinds of evaluation results was 0. 588 7 and was extremely significant. The five-level scoring method and the drought tolerance index can be used simultaneously for the evaluation of drought tolerance of maize during flowering stage. The two aspects of evaluation results showed that Guidan 0810,Zhengda 619,Xianyu 30 T60,Dika 008 and South America No. 1 were drought-tolerant varieties,among which Guidan 0810 and Zhengda 619 were extremely highly drought-tolerant varieties.展开更多
This study details the nature and magnitude of the genetic effects associated with various quantitative characters (morphological and hydric relations) measured in maize seedlings during the osmotic phase of saline st...This study details the nature and magnitude of the genetic effects associated with various quantitative characters (morphological and hydric relations) measured in maize seedlings during the osmotic phase of saline stress (100 mM NaCl). Three lines with differential behavior in salt stress: SC2 (tolerant), AFE (susceptible) and LP3 (moderately tolerant) were used to obtain contrasting crosses (SC2 × AFE) and (SC2 × LP3). An analysis of six generational means (P1, P2, F1, F2, BC1 and BC2) was applied for each cross. First a scaling test was applied and then a three and six-parameter genetic models were used to estimate various genetic components. In none of the traits studied there was evidence of adequacy to the three parameter model, which indicates important epistatic effects in genetic expression. The dominant genetic effects were greater than the additive ones for all the characters evaluated. LG showed positive and significant differences for [h] in both crosses, indicating the presence of hybrid vigor and its possible use in the improvement. Low value of [d] and high of [h] both significant in SC2 × AFE, indicates existence of genes dispersion between the parental lines. While, for the cross SC2 × LP3, the low and significant value of [d] and not significant value of [h], indicate greater genetic similarity. In the SC2 × LP3 cross, the negative interaction [l] confirms ambidirectional dominance, while for SC2 × LP3 the positive sign indicates directional dominance. The analysis of tolerance to salinity in the osmotic phase showed a complex polygenic inheritance for the traits used, determined by simple and interaction effects of different magnitudes and significance according to the cross considered.展开更多
To ascertain the genotypic difference of cadmium tolerance of different varieties of maize, effects of cadmium stress on the germination rate, germination index, vigor index, root length and fresh weight, and shoot le...To ascertain the genotypic difference of cadmium tolerance of different varieties of maize, effects of cadmium stress on the germination rate, germination index, vigor index, root length and fresh weight, and shoot length and fresh weight of seeds of 12 main varieties of maize widely cultivated in central Hunan were studied. The results showed that the cadmium stress had small impact on the germination rate and germination index of maize seeds, but it had obvious effects on the vigor index, root and shoot growth of maize seeds, and the inhibition effects on the roots were more obvious than the shoots. Among the 12 varieties of maize, Qiandan 12, Dushiliren, Nuobatianxia and Nongda 3138 were tolerant to cadmium stress, while Tianguan 218 was sensitive to cadmium stress, and the tolerance of other varieties of maize to cadmium stress was moderate.展开更多
Zinc(Zn)deficiency is the most widespread micronutrient deficiency,affecting yield and quality of crops worldwide.Identifying genes associated with Zn-deficiency tolerance in maize is a basis for elucidating its genet...Zinc(Zn)deficiency is the most widespread micronutrient deficiency,affecting yield and quality of crops worldwide.Identifying genes associated with Zn-deficiency tolerance in maize is a basis for elucidating its genetic mechanism.A K22×CI7 recombinant inbred population consisting of 210 lines and an association panel of 508 lines were used to identify genetic loci influencing Zn-deficiency tolerance.Under-Zn and-Zn/CK conditions,15 quantitative trait loci(QTL)were detected,each explaining 5.7%-12.6%of phenotypic variation.Sixty-one significant single-nucleotide polymorphisms(SNPs)were identified at P<10^(-5)by genome-wide association study(GWAS),accounting for 5%-14%of phenotypic variation.Among respectively 198 and 183 candidate genes identified within the QTL regions and the 100-kb regions flanking these significant SNPs,12 were associated with Zn-deficiency tolerance.Among these candidate genes,four genes associated with hormone signaling in response to Zn-deficiency stress were co-localized with QTL or SNPs,including the genes involved in the auxin(ZmARF7),and ethylene(ZmETR5,ZmESR14,and ZmEIN2)signaling pathways.Three candidate genes were identified as being responsible for Zn transport,including ZmNAS3 detected by GWAS,ZmVIT and ZmYSL11 detected by QTL mapping.Expression of ZmYSL11 was up-regulated in Zn-deficient shoots.Four candidate genes that displayed different expression patterns in response to Zn deficiency were detected in the regions overlapping peak GWAS signals,and the haplotypes for each candidate gene were further analyzed.展开更多
Maize is one of the most important cereal crops widely grown for food, feed, and fodder/forage throughout the world in a range of agroecological environments. Drought stress continues to haunt the maize farmers across...Maize is one of the most important cereal crops widely grown for food, feed, and fodder/forage throughout the world in a range of agroecological environments. Drought stress continues to haunt the maize farmers across south western part of Nigeria, thereby leading to low quantity of this essential staple food in the market. Efforts have been made to enhance the growths and yields in maize by investigating the influence of Arbuscular mycorrhizal fungus (Gigaspora gigantea) on the tolerance of maize to drought stress. The experiment was conducted in the teaching and research farm of Babcock University, Ilishan-Remo, Nigeria. The experiment was laid out in a complete randomized design with four replicates. Data were collected on eight morphological drought related characters. The objective of this research work was to evaluate the morpho-agronomic responses and potential of Gigaspora gigantea colonization in maize drought tolerance, and also to select parents in maize breeding for improved yield related components. The combined analysis of variance showed significant (P 0.05) treatment effect on majority of the traits evaluated. The treatments of Arbuscular Mycorrhiza Fungus (AMF) produced significant higher growth related traits suggesting that AMF treated plants had higher potential in influencing the tolerance to drought. Accession 3 was considered best for most of the traits studied and can be selected as parents in maize breeding for yield related components.展开更多
Over the past few decades,significant improvements in maize yield have been largely attributed to increased plant density of upright hybrid varieties rather than increased yield per plant.However,dense planting trigge...Over the past few decades,significant improvements in maize yield have been largely attributed to increased plant density of upright hybrid varieties rather than increased yield per plant.However,dense planting triggers shade avoidance responses(SARs)that optimize light absorption but impair plant vigor and performance,limiting yield improvement through increasing plant density.In this study,we demonstrated that high-density-induced leaf angle narrowing and stem/stalk elongation are largely dependent on phytochrome B(phyB1/B2),the primaryphotoreceptor responsible for perceiving red(R)and far-red(FR)light in maize.We found that maize phyB physically interacts with the LIGULELESS1(LG1),a classical key regulator of leaf angle,to coordinately regulate plant architecture and density tolerance.The abundance of LG1 is significantly increased by phyB under high R:FR light(low density)but rapidly decreases under low R:FR light(high density),correlating with variations in leaf angle and plant height under various densities.In addition,we identified the homeobox transcription factor HB53 as a target co-repressed by both phyB and LG1 but rapidly induced by canopy shade.Genetic and cellular analyses showed that HB53 regulates plant architecture by controlling the elongation and division of ligular adaxial and abaxial cells.Taken together,these findings uncover the phyB-LG1-HB53 regulatory module as a key molecular mechanism governing plant architecture and density tolerance,providing potential genetic targets for breeding maize hybrid varieties suitable for high-density planting.展开更多
Understanding how maize(Zea mays)responds to cold stress is crucial for facilitating breeding programs of cold-tolerant varieties.Despite extensive utilization of the genome-wide association study(GWAs)approach for ex...Understanding how maize(Zea mays)responds to cold stress is crucial for facilitating breeding programs of cold-tolerant varieties.Despite extensive utilization of the genome-wide association study(GWAs)approach for exploring favorable natural alleles associated with maize cold tolerance,few studies have successfully identified candidate genes that contribute to maize cold tolerance.In this study,we used a diverse panel of inbred maize lines collected from different germplasm sources to perform a GWAS on var-iations in the relative injured area of maize true leaves during cold stress-a trait very closely correlated with maize cold tolerance.We identified HsF21,which encodes a B-class heat shock transcription factor(HSF)that positively regulates cold tolerance at both the seedling and germination stages.Natural varia-tions in the promoter of the cold-tolerant HSF21Hap1 allele led to increased HSF21 expression under cold stress by inhibiting binding of the basic leucine zipper bziP68 transcription factor,a negative regulator of cold tolerance.By integrating transcriptome deep sequencing,DNA affinity purification sequencing,and targeted lipidomic analysis,we revealed the function of HsF21 in regulating lipid metabolism homeo-stasis to modulate cold tolerance in maize.In addition,we found that HsF21 confers maize cold tolerance without incurring yield penalties.Collectively,this study establishes HsF21 as a key regulator that en-hances cold tolerance in maize,providing valuable genetic resources for breeding of cold-tolerant maize varieties.展开更多
基金supported by the State Key Laboratory of North China Crop Improvement and Regulation(NCCIR2022ZZ-4)the Key Research and Development Projects of Hebei Province(21326319D)。
文摘Drought is a main abiotic stress factor hindering plant growth,development,and crop productivity.Therefore,it is crucial to understand the mechanisms by which plants cope with drought stress.Here,the function of the maize peroxidase gene ZmPRX1 in drought stress tolerance was investigated by measurement of its expression in response to drought treatment both in a ZmPRX1 overexpression line and a mutant line.The higher root lignin accumulation and seedling survival rate of the overexpression line than that of the wild type or mutant support a role for ZmPRX1 in maize drought tolerance by regulating root development and lignification.Additionally,yeast one-hybrid,Dule luciferase and ChIP-qPCR assays showed that ZmPRX1 is negatively regulated by a nuclear-localized ZmWRKY86 transcription factor.The gene could potentially be used for breeding of drought-tolerant cultivars.
基金supported by the National Natural Science Foundation of China(32101555,32001447,U2106229)China Postdoctoral Science Foundation(2021T140060,2020M670537)。
文摘Maize(Zea mays L.)is a global cereal crop whose demand is projected to double by 2050.Along with worsening of farmland salinization,salt stress has become a major environmental threat to the sustainability of maize production worldwide.Accordingly,there is an urgent need to decipher salt-tolerant mechanisms and facilitate the breeding of salt-tolerant maize.As salt tolerance is a complex trait regulated by multiple genes,and maize germplasm varies widely in salt tolerance,efforts have been devoted to the identification and application of quantitative-trait loci(QTL)for salt tolerance.QTL associated with ion regulation,osmotic tolerance,and other aspects of salt tolerance have been discovered using genomewide association studies(GWAS),linkage mapping,and omics-based approaches.This review highlights recent advances in the molecular-level understanding of salt stress response in maize,in particular in(a)the discovery of salt-tolerance QTL,(b)the mechanisms of salt tolerance,(c)the development of salttolerant maize cultivars,and(d)current challenges and future prospects.
基金Supported by the Corn Heat-resisting Resources Exploitation and Chain Molecular Marker Development(cstc2015jcyj BX0112)the Screening and Breeding of Feeding Maize Varieties in the Hilly and Mountain Areas(cstc2016shms-ztzx80017)+5 种基金the Functional Corn Germplasm Renounces Precise Identification and Material Innovation(cstc-2016shms-ztzx80013)the Breeding of Maize CMS Materials(2013cstc-jbky-00565)the Screening and Creation of High-temperature and Drought Resisting Corn Materials(2013cstc-jbky-00564)the Creation and Application of Shade-tolerant Corn Germplasm(cstc2016shmszx0218)the Special Fund for Scientific and Technological Innovation of Social People’s Livelihood of Chongqing Municipality-Molecular Analysis of Corn Kernel Accumulated Amylose and Development and Application of Genetic Specific Markers(cstc2015shmszx80029)the Innovation of Fine Varieties of Chongqing Academy of Agricultural Sciences-Research and Application of the Combining Ability of High-efficient Retrospective Improved Corn(NKY-2016AB004)~~
文摘Maize is an important food crop, as well as the irreplaceable feed and industrial materials, having huge market demand in China. Southwestern region of China is the third largest main maize producing zone, and the frequent occurrence of abiotic stress conditions such as drought, heat, cold, wet shaded stress have severely affected the development of maize production, causing low and unstable corn yields, severely restricting the maize industry development in the southwest of China. This paper preliminarily describes the maize resistance to abiotic stresses in southwestem region of China, putting forward the countermeasures and the key research direction in the practice of breeding in order to provide reference for the cultivation of new varieties with high yield and stress resistance, and improving the levels of maize stress resistance breeding in southwestern region of China.
基金Supported by National Special Fund for Construction of Technical System for Maize Industry of China(CARS-02-68)Science and Technology Supporting Program of Xinjiang Uygur Autonomous Region(201191220)+1 种基金Agriculture Science and Technology Achievement Transformation Fund of Xinjiang Uygur Autonomous Region(2011GB2G400001)Science and Technology Supporting Program of Xinjiang Uygur Autonomous Region(201231104)~~
文摘By using complete-diallel cross design(Griffing method I), the influence of the combination of different high-yield genotypes of maize on the drought tolerance of their offspring, the general combining ability, the specific combining ability and the back cross effect of drought tolerance between parents and the main genetic parameters for drought tolerance were analyzed. The result indicated that there were significant differences in general combining ability effects(GCA) of maize; there were highly significant differences in special combining ability effects(SCA); there was no significant difference in reciprocal effects(R). There were apparent differences in drought tolerance among six parents; to be specific, Zheng 58 had the highest drought tolerance, while PH4CV had the lowest. Improving drought-tolerant parents with Zheng 58, Ji 853 and Xinzi 8717 had gain superiority effects on the increase of drought tolerance in offspring. The influence of the genetic additive effect on the drought tolerance of offsprings varied with different parents and combinations. Therefore, the expression of drought tolerance inheritance genes was determined only by the additive and non-additive genetic effects but had little relationship with reciprocal effects. The selection of drought tolerance of maize should be conducted at higher generations.
基金supported by the Natural Science Foundation of Hubei Province, China (2008CDB079)the National High Technology Research and Development Program of China (863 Program,2006AA100103)
文摘Waterlogging strongly affects agronomic performance of maize (Zea mays L.). In order to investigate the suitable selection criteria of waterflooding tolerant genotypes, and identify the most susceptible stage and the best continuous treatment time to waterlogging, 20 common maize inbred lines were subjected to successive artificial waterflooding at seedling stage, and waterlogging tolerance coefficient (WTC) was used to screen waterflooding tolerant genotypes. In addition, peroxidase (POD) activities and malondialdehyde (MDA) contents were measured for 6 of 20 lines. The results showed that the second leaf stage (V2) was the most susceptible stage, and 6 d after waterflooding was the best continuous treatment time. Dry weight (DW) of both shoots and roots of all lines were significantly reduced at 6 d time-point of waterlogging, compared to control. POD activities and MDA contents were negatively and significantly correlated, and the correlation coefficient was -0.9686 (P 〈 0.0001). According to the results, WTC of shoot DW can be used for practical screening as a suitable index, which is significantly different from control and waterlogged plants happened 6 d earlier. Furthermore, leaf chlorosis, MDA content and POD activities could also be used as reference index for material screening. The implications of the results for waterlogging-tolerant material screening and waterlogging-tolerant breeding have been discussed in maize.
基金supported by the National Basic Research Program of China (2009CB118400)
文摘Drought is a major constraint in maize production worldwide. We studied quantitative trait loci (QTL) underlying drought tolerance for maize plants grown in two different environments. Traits investigated included ASI, plant height, grain yield, ear height, and ear setting. A genetic linkage map was constructed with 120 simple sequence repeat (SSR) markers based on an F2 population derived from a cross between D5 (resistant parent) and 7924 (susceptible parent). Correlation and heritability were calculated. QTLs of these traits were identified by composite interval mapping combined with a linkage map covering 1 790.3 cM. The markers were arranged in ten linkage groups. QTL mapping was made of the mean trait performance of the 180 F2:3 population. The results showed five, five, six, four, and five QTLs for ASI, plant height, grain yield, ear height, and ear setting under full irrigation condition, respectively, and four, seven, six, four, and four QTLs for ASI, plant height, grain yield, ear height, and ear setting under severe late stress conditions, respectively. Especially the four QTLs detected for five traits in 2008 and 2009. The universal QTLs information generated in this study will aid in undertaking an integrated breeding strategy for further genetic studies in drought tolerance improvement in maize.
基金This work was supported by the National 863 Program of China(2001AA241051).
文摘Phosphorus nutrient characteristics of different maize inbred lines to low-P stress were studied at stages of seedling, steming, earing, silking under pot culture. In the periods of seedling and steming, P uptake efficiency was the main contributor to P tolerance, and the relative P content in P-tolerant genotypes, 99180 and 99239 were higher than that in sensitive genotype, 99152. At earing stage, P-tolerant genotypes, compared to P-sensitive ones, had higher accumulation of P in upper leaves. When came to the silking stage, P uptake and redistribution efficiency of P-tolerant genotypes were higher than those in 99152. The results also suggested that there are different mechanisms of P nutrient uptake and distribution in different P-tolerant genotypes. Inbred line 99239, according to the investigation, was considered as an efficient stock in the P-uptake while 99180 fallen to the efficient stock of P redistribution.
基金funded by the National Major Project for Transgenic Organism Breeding, China (2014ZX08010-004)
文摘It has previously been shown that a bacterial 5-enolpyruvylshikimate-3-phosphate synthase(EPSPS) encoding gene AM79 aroA can be a candidate gene to develop glyphosate-tolerant transgenic crops(Cao et al. 2012). In this study, AM79 aroA was redesigned using the plant biased codons and eliminating the motifs which would lead to the instability of mRNA, to create a synthetic gene that would be expressed highly in plant cells. The redesigned and artificially synthesized gene, named as mAM79, was cloned into plant expression vector pM3301 Ubi Sp AM79, where mAM79 is fused with signal peptide sequence of pea rib-1,5-bisphospate carboxylase(rbcS) small subunit and controlled by ubiquitin promoter. The plasmid was transformed into maize(Zea mays) immature embryos using Agrobacterium-mediated transformation method. Total 74 regenerated plants were obtained and PCR analysis showed that these transgenic plants had the integration of mAM79. Southern blot analysis was performed on the genomic DNA from four transgenic lines, and the result showed that one or two copies of mAM79 were integrated into maize genome. RT-PCR analysis result indicated that mAM79 was highly transcribed in transgenic maize plants. When sprayed with glyphosate, transgenic maize line AM85 and AM72 could tolerate 4-fold of commercial usage of glyphosate; however, all the non-transgenic maize plants were killed by glyphosate. The results in this study confirmed that mAM79 could be used to develop glyphosate-tolerant maize, and the obtained transgenic maize lines could be used for the breeding of glyphosate-tolerant maize.
基金supported by the National Natural Science Foundation of China (31701361, 31401331)the earmarked fund for China Agriculture Research System (CARS-02-26)
文摘Maize growth and development is affected by low temperature(LT) especially at the early stages of development. To describe the response of different varieties to LT stress and determine an effective method to cope with LT stress, maize hybrids Zhengdan 958(ZD 958) and Danyu 39(DY 39) were planted and grown at 10 and 25°C, respectively. Effects of the chemicals potassium chloride(KCl), gibberellin(GA), 2-diethylaminoethyl-3,4-dichlorophenylether(DCPTA), and all three combined chemicals(KGD) on coping with LT stress were tested by seed priming. The varieties performed significantly different at 10°C. Compared to leaf, root growth was more severely affected by LT stress. Root/leaf ratio is likely a more reliable parameter to evaluate cold tolerance based on its close correlation with leaf malondialdehyde(MDA) content(R=–0.8). GAadvanced seed germination by about 2 days compared with control treatment of water. GAand DCPTA both resulted in lower leaf MDA content and higher leaf and root area, and root/leaf ratio. KCl resulted in the highest evenness of plant height. KGD performed the best in increasing cold tolerance of maize morphologically and physiologically. Strategies to increase maize tolerance of cold stress, such as variety breeding or chemical selection, would increase maize yield especially at high-latitude regions and have great implications for food security.
基金support of the National Natural Science Foundation of China(30771383)the Genetically Modified Organisms Breeding Major Projects, China(2013ZX08003-001)the National Basic Research Program of China (2009CB118902)
文摘Using linker peptide LP4/2A for multiple gene transformation is considered to be an effective method to stack or pyramid several traits in plants. Bacillus thuringiensis(Bt) cry gene and epsps(5-enolpyruvylshikimate-3-phosphate synthase) gene are two important genes for culturing pest-resistant and glyphosate-tolerant crops. We used linker peptide LP4/2A to connect the Bt cry1 Ah gene with the 2m G2-epsps gene and combined the wide-used man A gene as a selective marker to construct one coordinated expression vector called p2 EPUHLAGN. The expression vector was transferred into maize by Agrobacterium tumefaciens-mediated transformation, and 60 plants were obtained, 40% of which were positive transformants. Molecular detection demonstrated that the two genes in the fusion vector were expressed simultaneously and spliced correctly in translation processing; meanwhile bioassay detection proved the transgenic maize had preferable pest resistance and glyphosate tolerance. Therefore, linker peptide LP4/2A provided a simple and reliable strategy for producing gene stacking in maize and the result showed that the fusion gene transformation system of LP4/2A was feasible in monocot plants.
文摘Thirteen different inbred lines in relation to the type of grain and life cycles were characterized by testing for osmotic stress associated with salinity. The identification of tolerant genotypes would be an effective strategy to overcome the saline stress. Osmotic stress reduces immediately the expansion of the roots and young leaves which determine a reduction in the size of the plant. A completely randomized design was adopted to test seedlings under controlled conditions of light and temperature. Two treatments were used: 0 mM NaCl (as control) and 100 mM NaCl. After 15 days of complete salinization, the seedlings were harvested and several morphological traits were measured. The morphological traits of growth were leaf growth (Ar1, Ar2, Ar3 and Ar4), dry masses of shoot and root (SDM and RDM, respectively). Also, traits associated with water economy were registered: leaf water loss (LWL) and relative water content (RWC). The morphological traits were expressed in relative terms, while the traits associated with the economy of water were expressed in absolute terms. Uni and multivariate techniques were applied to identify genotypes with divergent behaviors to osmotic stress tolerance. Also, a Tolerance Index was employed to identify superior genotypes. Four clusters were obtained after applying a Cluster Analysis and Principal Component Analysis (PCA). The genotypes were compared to each other with a test of DMS. The results obtained with different statistical techniques converged. Some variables presented a differential weight classification of genotypes. The morphological traits like RDM, SDM, Ar3, Ar4 and Ar5 were the most discriminating. Tolerance Index allowed to classify genotypes, thus SC2 and AD3 lines were that reached highest value of the index and therefore would be tolerant lines, while AF3 and LP3 had a low index and were seen as sensible.
文摘Six tropical maize inbred lines were crossed in a half diallel fashion and evaluated along with their F1 hybrids under low N (0 kg/ha) and high N(170 kg/ha), for grain yield, ear diameter, ear length, number of rows per ear, 100-kernel weight, ear leaf area, shoot dry weight, ear leaf chlorophyll content and plant height to determine their response to different level of N. Grain yield and ear leaf chlorophyll content measured by 48% lower under -N than under + N, and were most affected by -N. Ear length had the highest reduction under -N of 22%. Plant height and shoot dry weight were both reduced by 28%. Diallel analysis indicated significant additive as well as dominance variance for grain yield under -N. The same results were shown when one tolerant x nontolerant cross from the diallel hybrids was subjected to generation mean analysis which also indicated significant epistatic effects. These results suggest that S1 or S2 progeny selection may be an effective means of improving grain yield of tropical maize under low soil N.
基金Supported by Project of Key Opening Laboratory of Physiology and Ecology of Crop in Cold Terra of Agriculture MinistryProject of the Department of Education of Heilongjiang Province (11521196)
文摘[ Objective] This study aimed to map quantitative tarit loci (QTLs) associated with salt tolerance of maize inbred line at seedling stage. [ Method! The recombinant inbred line (RIL) F7 including 171 plants were developed by single seed descent procedure from a combination, Huangzazsi × Mo17, and used to map QTLs associated with salt tolerance, based on the constructed genetic map of SSR markers. [ Resultl A linkage map consisting of 81 SSR markers loci from 10 chromosomes ( 1 428.3 cM in total length, with an average distance of 17.63 cM between two neighbouring loci) was constructed. Six QTI~ associated significantly with salt tolerance were detected at chromosomes 1,5 and 6. [ Conclusion] This study is extremely significant for better understanding sah tolerance-related genes, the genes' location and cloning, salt tolerance mechanism and the marker-assisted selection of salt tolerant maize.
基金Supported by National Key Research and Development Program of China(2018YFD0100105-1)Earmarked Fund for China Agriculture Research System(nycytxgxcxtd)+2 种基金Science and Technology Major Project of Guangxi(Gui Ke AA17204064)Fundamental Research Funds of Guangxi Academy of Agricultural Sciences(Gui Nong Ke 2016YM42)Science and Technology Development Fund of Maize Research Institute,Guangxi Academy of Agricultural Sciences(Yu ZX2015001)
文摘Total 20 maize varieties were subjected to drought stress at flowering stage,and then the relative water content,soluble sugar content,chlorophyll content,malondialdehyde( MDA) content and superoxide dismutase( SOD) activity in their leaves,as well as their yields were determined. The drought tolerance of the physiological and biochemical indexes was scored by five-level scoring method,and the drought tolerance index was calculated by the yield index to comprehensively evaluate the drought tolerance of maize during flowering stage. The results showed that the scores of drought tolerance of the maize varieties ranged from 1. 929 3 to 5. 659 5. Among them,the scores of Zhengda 619,Guidan 162 and Guidan 0810 were greater than 5. 0,followed by Dika 008,Xianyu 30 T60,Xianzhengda 901,Qingnong 68,South America No. 1 and Wanchuan 1306 of which the scores were in the range of 4. 0-5. 0. The drought tolerance indexes were in the range of 0. 410 4-1. 096 3. Among the test maize varieties,the drought tolerance indexes of Guidan 0810,Pacific 99 and Zhengda 619 were greater than 1. 0,and those of Xianyu 30 T60,Dika 008 and South America No. 1 were in the range of 0. 9-1. 0. The correlation between the two kinds of evaluation results was 0. 588 7 and was extremely significant. The five-level scoring method and the drought tolerance index can be used simultaneously for the evaluation of drought tolerance of maize during flowering stage. The two aspects of evaluation results showed that Guidan 0810,Zhengda 619,Xianyu 30 T60,Dika 008 and South America No. 1 were drought-tolerant varieties,among which Guidan 0810 and Zhengda 619 were extremely highly drought-tolerant varieties.
文摘This study details the nature and magnitude of the genetic effects associated with various quantitative characters (morphological and hydric relations) measured in maize seedlings during the osmotic phase of saline stress (100 mM NaCl). Three lines with differential behavior in salt stress: SC2 (tolerant), AFE (susceptible) and LP3 (moderately tolerant) were used to obtain contrasting crosses (SC2 × AFE) and (SC2 × LP3). An analysis of six generational means (P1, P2, F1, F2, BC1 and BC2) was applied for each cross. First a scaling test was applied and then a three and six-parameter genetic models were used to estimate various genetic components. In none of the traits studied there was evidence of adequacy to the three parameter model, which indicates important epistatic effects in genetic expression. The dominant genetic effects were greater than the additive ones for all the characters evaluated. LG showed positive and significant differences for [h] in both crosses, indicating the presence of hybrid vigor and its possible use in the improvement. Low value of [d] and high of [h] both significant in SC2 × AFE, indicates existence of genes dispersion between the parental lines. While, for the cross SC2 × LP3, the low and significant value of [d] and not significant value of [h], indicate greater genetic similarity. In the SC2 × LP3 cross, the negative interaction [l] confirms ambidirectional dominance, while for SC2 × LP3 the positive sign indicates directional dominance. The analysis of tolerance to salinity in the osmotic phase showed a complex polygenic inheritance for the traits used, determined by simple and interaction effects of different magnitudes and significance according to the cross considered.
基金Supported by Key Laboratory of Pesticide Harmless Application of an University in Hunan Province
文摘To ascertain the genotypic difference of cadmium tolerance of different varieties of maize, effects of cadmium stress on the germination rate, germination index, vigor index, root length and fresh weight, and shoot length and fresh weight of seeds of 12 main varieties of maize widely cultivated in central Hunan were studied. The results showed that the cadmium stress had small impact on the germination rate and germination index of maize seeds, but it had obvious effects on the vigor index, root and shoot growth of maize seeds, and the inhibition effects on the roots were more obvious than the shoots. Among the 12 varieties of maize, Qiandan 12, Dushiliren, Nuobatianxia and Nongda 3138 were tolerant to cadmium stress, while Tianguan 218 was sensitive to cadmium stress, and the tolerance of other varieties of maize to cadmium stress was moderate.
基金supported by the National Key Research and Development Program of China(2016YFD0200405)。
文摘Zinc(Zn)deficiency is the most widespread micronutrient deficiency,affecting yield and quality of crops worldwide.Identifying genes associated with Zn-deficiency tolerance in maize is a basis for elucidating its genetic mechanism.A K22×CI7 recombinant inbred population consisting of 210 lines and an association panel of 508 lines were used to identify genetic loci influencing Zn-deficiency tolerance.Under-Zn and-Zn/CK conditions,15 quantitative trait loci(QTL)were detected,each explaining 5.7%-12.6%of phenotypic variation.Sixty-one significant single-nucleotide polymorphisms(SNPs)were identified at P<10^(-5)by genome-wide association study(GWAS),accounting for 5%-14%of phenotypic variation.Among respectively 198 and 183 candidate genes identified within the QTL regions and the 100-kb regions flanking these significant SNPs,12 were associated with Zn-deficiency tolerance.Among these candidate genes,four genes associated with hormone signaling in response to Zn-deficiency stress were co-localized with QTL or SNPs,including the genes involved in the auxin(ZmARF7),and ethylene(ZmETR5,ZmESR14,and ZmEIN2)signaling pathways.Three candidate genes were identified as being responsible for Zn transport,including ZmNAS3 detected by GWAS,ZmVIT and ZmYSL11 detected by QTL mapping.Expression of ZmYSL11 was up-regulated in Zn-deficient shoots.Four candidate genes that displayed different expression patterns in response to Zn deficiency were detected in the regions overlapping peak GWAS signals,and the haplotypes for each candidate gene were further analyzed.
文摘Maize is one of the most important cereal crops widely grown for food, feed, and fodder/forage throughout the world in a range of agroecological environments. Drought stress continues to haunt the maize farmers across south western part of Nigeria, thereby leading to low quantity of this essential staple food in the market. Efforts have been made to enhance the growths and yields in maize by investigating the influence of Arbuscular mycorrhizal fungus (Gigaspora gigantea) on the tolerance of maize to drought stress. The experiment was conducted in the teaching and research farm of Babcock University, Ilishan-Remo, Nigeria. The experiment was laid out in a complete randomized design with four replicates. Data were collected on eight morphological drought related characters. The objective of this research work was to evaluate the morpho-agronomic responses and potential of Gigaspora gigantea colonization in maize drought tolerance, and also to select parents in maize breeding for improved yield related components. The combined analysis of variance showed significant (P 0.05) treatment effect on majority of the traits evaluated. The treatments of Arbuscular Mycorrhiza Fungus (AMF) produced significant higher growth related traits suggesting that AMF treated plants had higher potential in influencing the tolerance to drought. Accession 3 was considered best for most of the traits studied and can be selected as parents in maize breeding for yield related components.
基金the National Natural Science Foundation of China(32270263 to G.L.,32130077 to H.W.,and 32272140 to P.L.)the Shandong Provincial Natural Science Foundation(ZR2022QC095,ZR2020MC023,ZR2022MC019).
文摘Over the past few decades,significant improvements in maize yield have been largely attributed to increased plant density of upright hybrid varieties rather than increased yield per plant.However,dense planting triggers shade avoidance responses(SARs)that optimize light absorption but impair plant vigor and performance,limiting yield improvement through increasing plant density.In this study,we demonstrated that high-density-induced leaf angle narrowing and stem/stalk elongation are largely dependent on phytochrome B(phyB1/B2),the primaryphotoreceptor responsible for perceiving red(R)and far-red(FR)light in maize.We found that maize phyB physically interacts with the LIGULELESS1(LG1),a classical key regulator of leaf angle,to coordinately regulate plant architecture and density tolerance.The abundance of LG1 is significantly increased by phyB under high R:FR light(low density)but rapidly decreases under low R:FR light(high density),correlating with variations in leaf angle and plant height under various densities.In addition,we identified the homeobox transcription factor HB53 as a target co-repressed by both phyB and LG1 but rapidly induced by canopy shade.Genetic and cellular analyses showed that HB53 regulates plant architecture by controlling the elongation and division of ligular adaxial and abaxial cells.Taken together,these findings uncover the phyB-LG1-HB53 regulatory module as a key molecular mechanism governing plant architecture and density tolerance,providing potential genetic targets for breeding maize hybrid varieties suitable for high-density planting.
基金supported by Biological Breeding-National Science and Technology Major Project of China(2023ZD0407104)the National Natural Science Foundation of China(32272025 and 31730011)the Pinduoduo-China Agricultural University Research Fund(PC2023B01001),and the Chinese Universities Scientific Fund.
文摘Understanding how maize(Zea mays)responds to cold stress is crucial for facilitating breeding programs of cold-tolerant varieties.Despite extensive utilization of the genome-wide association study(GWAs)approach for exploring favorable natural alleles associated with maize cold tolerance,few studies have successfully identified candidate genes that contribute to maize cold tolerance.In this study,we used a diverse panel of inbred maize lines collected from different germplasm sources to perform a GWAS on var-iations in the relative injured area of maize true leaves during cold stress-a trait very closely correlated with maize cold tolerance.We identified HsF21,which encodes a B-class heat shock transcription factor(HSF)that positively regulates cold tolerance at both the seedling and germination stages.Natural varia-tions in the promoter of the cold-tolerant HSF21Hap1 allele led to increased HSF21 expression under cold stress by inhibiting binding of the basic leucine zipper bziP68 transcription factor,a negative regulator of cold tolerance.By integrating transcriptome deep sequencing,DNA affinity purification sequencing,and targeted lipidomic analysis,we revealed the function of HsF21 in regulating lipid metabolism homeo-stasis to modulate cold tolerance in maize.In addition,we found that HsF21 confers maize cold tolerance without incurring yield penalties.Collectively,this study establishes HsF21 as a key regulator that en-hances cold tolerance in maize,providing valuable genetic resources for breeding of cold-tolerant maize varieties.