Soil salinity affects the expression of serine/arginine-rich(SR) genes and isoforms by alternative splicing, which in turn regulates the adaptation of plants to stress.We previously identified the cassava spliceosomal...Soil salinity affects the expression of serine/arginine-rich(SR) genes and isoforms by alternative splicing, which in turn regulates the adaptation of plants to stress.We previously identified the cassava spliceosomal component 35 like(SCL) and SR subfamilies, belonging to the SR protein family, which are extensively involved in responses to abiotic stresses.However, the post-transcriptional regulatory mechanism of cassava arginine/serine-rich(RS) subfamily in response to salt stress remains to be explored.In the current study, we identified 37 genes of the RS subfamily from 11 plant species and systematically investigated the transcript levels of the RS40 and RS31 genes under diverse abiotic stress conditions.Subsequently, an analysis of the conserved protein domains revealed that plant RS subfamily genes were likely to preserve their conserved molecular functions and played critical functional roles in responses to abiotic stresses.Importantly, we found that overexpression of MeRS40 in Arabidopsis enhanced salt tolerance by maintaining reactive oxygen species homeostasis and up-regulating the salt-responsive genes.However,overexpression of MeRS40 gene in cassava reduced salt tolerance due to the depression of its endogenous gene expression by negative autoregulation of its own pre-mRNA.Moreover, the MeRS40 protein interacted with MeU1-70Ks(MeU1-70Ka and MeU1-70Kb) in vivo and in vitro, respectively.Therefore, our findings highlight the critical role of cassava SR proteins in responses to salt stress in plants.展开更多
Tea is one of the most popular healthy and non-alcoholic beverages worldwide.Tea anthracnose is a disease in tea mature leaves and ultimately affects yield and quality.Colletotrichum camelliae is a dominant fungal pat...Tea is one of the most popular healthy and non-alcoholic beverages worldwide.Tea anthracnose is a disease in tea mature leaves and ultimately affects yield and quality.Colletotrichum camelliae is a dominant fungal pathogen in the tea field that infects tea plants in China.The pathogenic factors of fungus and the susceptible factors in the tea plant are not known.In this work,we performed molecular and genetic studies to observe a cerato-platanin protein CcCp1 from C.camelliae,which played a key role in fungal pathogenicity.CcCp1 mutants lost fungal virulence and reduced the ability to produce conidia.Transcriptome and metabolome were then performed and analysed in tea-susceptible and tea-resistant cultivars,Longjing 43 and Zhongcha 108,upon C.camelliae wild-type CCA andCcCp1 infection,respectively.The differentially expressed genes and the differentially accumulated metabolites in tea plants were clearly overrepresented such as linolenic acid and linoleic acid metabolism,glycerophospholipid metabolism,phenylalanine biosynthesis and metabolism,biosynthesis of f lavonoid,f lavone and f lavonol etc.In particular,the accumulation of jasmonic acid was significantly increased in the susceptible cultivar Longjing 43 upon CCA infection,in the fungal CcCp1 protein dependent manner,suggesting the compound involved in regulating fungal infection.In addition,other metabolites in the glycerophospholipid and phenylalanine pathway were observed in the resistant cultivar Zhongcha 108 upon fungal treatment,suggesting their potential role in defense response.Taken together,this work indicated C.camelliae CcCp1 affected the tea plant lipid metabolism pathway to promote disease while the lost function of CcCp1 mutants altered the fungal virulence and plant response.展开更多
Salt stress is a major environmental stress that threats crop growth and yield.It is of great significance to study the molecular genetic network of plants in response to salt stress and to cultivate salt-tolerant cro...Salt stress is a major environmental stress that threats crop growth and yield.It is of great significance to study the molecular genetic network of plants in response to salt stress and to cultivate salt-tolerant crop varieties for national food security.A study published in Nature Plants,Dr.ZHAO Chunzhao’s group from the CAS Center for Excellence in Molecular Plant Sciences(CEMPS),Chinese Academy of Science,uncovers a novel mechanism underlying the coordination of plant growth and salt tolerance in plants.展开更多
虎耳草属(Saxifraga Tourn. ex L.)资源丰富且分布广泛,全球有440~500个种,其分类一直受到植物学家的关注。该属具有重要的观赏和药用价值,欧洲多国非常重视其观赏资源的开发利用。虎耳草属的品种培育距今已有150多年的历史,到2022年国...虎耳草属(Saxifraga Tourn. ex L.)资源丰富且分布广泛,全球有440~500个种,其分类一直受到植物学家的关注。该属具有重要的观赏和药用价值,欧洲多国非常重视其观赏资源的开发利用。虎耳草属的品种培育距今已有150多年的历史,到2022年国际虎耳草协会(The Saxifrage Society)网站收录了1 692个品种,但只有1个品种来自中国。可见,我国虽然是虎耳草属的多样性中心之一,但对其观赏资源的开发利用远远落后于欧美甚至日本。该文从虎耳草属的种质资源、分类概况、育种进展等方面进行综述,并简要介绍该属资源的利用现状,为今后我国虎耳草属的分类、育种及应用提供借鉴。结果表明:(1)虎耳草种质资源丰富,但属下系统演化关系仍存在诸多问题,有待整合形态和系统发育学手段开展系统而深入的研究。(2)该属品种主要通过杂交育种和变异筛选的方式育成,英国、捷克共和国、德国、荷兰为培育品种最多的国家。(3)我国对该属的品种选育工作起步晚,育成品种少且育种方式单一。展开更多
Biogeographical barriers to gene flow are central to plant phylogeography.In East Asia,plant distribution is greatly influenced by two phylogeographic breaks,the Mekong-Salween Divide and Tanaka-Kaiyong Line,however,f...Biogeographical barriers to gene flow are central to plant phylogeography.In East Asia,plant distribution is greatly influenced by two phylogeographic breaks,the Mekong-Salween Divide and Tanaka-Kaiyong Line,however,few studies have investigated how these barriers affect the genetic diversity of species that are distributed across both.Here we used 14 microsatellite loci and four chloroplast DNA fragments to examine genetic diversity and distribution patterns of 49 populations of Populus rotundifolia,a species that spans both the Mekong-Salween Divide and the Tanaka-Kaiyong Line in southwestern China.Demographic and migration hypotheses were tested using coalescent-based approaches.Limited historical gene flow was observed between the western and eastern groups of P.rotundifolia,but substantial flow occurred across both the Mekong-Salween Divide and Tanaka-Kaiyong Line,manifesting in clear admixture and high genetic diversity in the central group.Wind-borne pollen and seeds may have facilitated the dispersal of P.rotundifolia following prevalent northwest winds in the spring.We also found that the Hengduan Mountains,where multiple genetic barriers were detected,acted on the whole as a barrier between the western and eastern groups of P.rotundifolia.Ecological niche modeling suggested that P.rotundifolia has undergone range expansion since the last glacial maximum,and demographic reconstruction indicated an earlier population expansion around 600 Ka.The phylogeographic pattern of P.rotundifolia reflects the interplay of biological traits,wind patterns,barriers,niche differentiation,and Quaternary climate history.This study emphasizes the need for multiple lines of evidence in understanding the Quaternary evolution of plants in topographically complex areas.展开更多
Endangered species generally have small populations with low genetic diversity and a high genetic load.Thuja sutchuenensis is an endangered conifer endemic to southwestern China.It was once considered extinct in the w...Endangered species generally have small populations with low genetic diversity and a high genetic load.Thuja sutchuenensis is an endangered conifer endemic to southwestern China.It was once considered extinct in the wild,but in 1999 was rediscovered.However,little is known about its genetic load.We collected 67 individuals from five wild,isolated T.sutchuenensis populations,and used 636,151 SNPs to analyze the level of genetic diversity and genetic load in T.sutchuenensis to delineate the conservation units of T.sutchuenensis,based on whole transcriptome sequencing data,as well as target capture sequencing data.We found that populations of T.sutchuenensis could be divided into three groups.These groups had low levels genetic diversity and were moderately genetically differentiated.Our findings also indicate that T.sutchuenensis suffered two severe bottlenecks around the Last Glaciation Period and Last Glacial Maximum.Among Thuja species,T.sutchuenensis presented the lowest genetic load and hence might have purged deleterious mutations efficiently through purifying selection.However,distribution of fitness effects analysis indicated a high extinction risk for T.sutchuenensis.Multiple lines of evidence identified three management units for T.sutchuenensis.Although T.sutchuenensis possesses a low genetic load,low genetic diversity,suboptimal fitness,and anthropogenic pressures all present an extinction risk for this rare conifer.This might also hold true for many endangered plant species in the mountains all over the world.展开更多
Plasma membrane intrinsic proteins(PIPs)are conserved plant aquaporins that transport small molecules across the plasma membrane to trigger instant stress responses and maintain cellular homeostasis under biotic and a...Plasma membrane intrinsic proteins(PIPs)are conserved plant aquaporins that transport small molecules across the plasma membrane to trigger instant stress responses and maintain cellular homeostasis under biotic and abiotic stress.To elucidate their roles in plant immunity to pathogen attack,we characterized the expression patterns,subcellular localizations,and H_(2)O_(2)-transport ability of 11 OsPIPs in rice(Oryza sativa),and identified OsPIP2;6 as necessary for rice disease resistance.OsPIP2;6 resides on the plasma membrane and facilitates cytoplasmic import of the immune signaling molecule H_(2)O_(2).Knockout of OsPIP2;6 increases rice susceptibility to Magnaporthe oryzae,indicating a positive function in plant immunity.OsPIP2;6 interacts with OsPIP2;2,which has been reported to increase rice resistance to pathogens via H_(2)O_(2)transport.Our findings suggest that OsPIP2;6 cooperates with OsPIP2;2 as a defense signal transporter complex during plant–pathogen interaction.展开更多
The mitogen-activated protein kinase (MAPK), a key signal transduction component in the MAPK cascade pathway, regulates a variety of physiological activities in eukaryotes. However, little is known of the role MAPK ...The mitogen-activated protein kinase (MAPK), a key signal transduction component in the MAPK cascade pathway, regulates a variety of physiological activities in eukaryotes. However, little is known of the role MAPK plays in phytopathogenic fungi. In this research, we cloned the MAPK gene STK1 from the northern corn leaf blight pathogen Setosphaeria turcica and found that the gene shared high homology with the high osmolality glycerol (HOG) MAPK gene HOG1 of Saccharomy- ces cerevisiae. In addition, gene knockout technology was employed to investigate the function of STKI. Gene knockout mutants (KOs) were found to have altered hyphae morphology and no conidiogenesis, though they did show similar radial growth rate compared to the wild-type strain (WT). Furthermore, microscope observations indicated that STK1 KOs did not form normal appressoria at 48 h post-inoculation on a hydrophobic surface. STK1 KOs had reduced virulence, a significantly altered Helminthosporium turcicum (HT)-toxin composition, and diminished pathogenicity on the leaves of susceptible inbred corn OH43. Mycelium morphology appeared to be significantly swollen and the radial growth rates of STK1 KOs declined in comparison with WT under high osmotic stress. These results suggested that STK1 affects the hyphae development, conidiogenesis, and pathogenicity of S. turcica by regulating appressorium development and HT-toxin biosynthesis. Moreover, the gene appears to be involved in the hypertonic stress response in S. turcica.展开更多
Under high light conditions or UV radiation,tea plant leaves produce more flavonols,which contribute to the bitter taste of tea;however,neither the flavonol biosynthesis pathways nor the regulation of their production...Under high light conditions or UV radiation,tea plant leaves produce more flavonols,which contribute to the bitter taste of tea;however,neither the flavonol biosynthesis pathways nor the regulation of their production are well understood.Intriguingly,tea leaf flavonols are enhanced by UV-B but reduced by shading treatment.CsFLS,CsUGT78A14,CsMYB12,and CsbZIP1 were upregulated by UV-B radiation and downregulated by shading.CsMYB12 and CsbZIP1 bound to the promoters of CsFLS and CsUGT78A14,respectively,and activated their expression individually.CsbZIP1 positively regulated CsMYB12 and interacted with CsMYB12,which specifically activated flavonol biosynthesis.Meanwhile,CsPIF3 and two MYB repressor genes,CsMYB4 and CsMYB7,displayed expression patterns opposite to that of CsMYB12.CsMYB4 and CsMYB7 bound to CsFLS and CsUGT78A14 and repressed their CsMYB12-activated expression.While CsbZIP1 and CsMYB12 regulated neither CsMYB4 nor CsMYB7,CsMYB12 interacted with CsbZIP1,CsMYB4,and CsMYB7,but CsbZIP1 did not physically interact with CsMYB4 or CsMYB7.Finally,CsPIF3 bound to and activated CsMYB7 under shading to repress flavonol biosynthesis.These combined results suggest that UV activation and shading repression of flavonol biosynthesis in tea leaves are coordinated through a complex network involving CsbZIP1 and CsPIF3 as positive MYB activators and negative MYB repressors,respectively.The study thus provides insight into the regulatory mechanism underlying the production of bitter-tasting flavonols in tea plants.展开更多
Global warming threatens food security.Rice(Oryza sativa L.),a vital food crop,is vulnerable to heat stress,especially at the reproductive stage.Here we summarize putative mechanisms of high-temperature perception(via...Global warming threatens food security.Rice(Oryza sativa L.),a vital food crop,is vulnerable to heat stress,especially at the reproductive stage.Here we summarize putative mechanisms of high-temperature perception(via RNA secondary structure,the phyB gene,and phase separation)and response(membrane fluidity,heat shock factors,heat shock proteins,and ROS(reactive oxygen species)scavenging)in plants.We describe how rice responds to heat stress at different cell-component levels(membrane,endoplasmic reticulum,chloroplasts,and mitochondria)and functional levels(denatured protein elimination,ROS scavenging,stabilization of DNA and RNA,translation,and metabolic flux changes).We list temperature-sensitive genetic male sterility loci available for use in rice hybrid breeding and explain the regulatory mechanisms associated with some of them.Breeding thermotolerant rice species without yield penalties via natural alleles mining and transgenic editing should be the focus of future work.展开更多
A universal method of molecular dating that can be applied to all families and genera regardless of their fossil records, or lack thereof, is highly desirable. A possible method for eudicots is to use a large phylogen...A universal method of molecular dating that can be applied to all families and genera regardless of their fossil records, or lack thereof, is highly desirable. A possible method for eudicots is to use a large phylogeny calibrated using deep fossils including tricolpate pollen as a fixed (124 mya) calibration point. This method was used to calculate node ages within three species-poor disjunct basal eudicot genera, Caulophyllum, Podophyllum and Pachysandra, and sensitivity of these ages to effects such as taxon sampling were then quantified. By deleting from one to three accessions related to each genus in 112 different combinations, a confidence range describing variation due only to taxon sampling was generated. Ranges for Caulophyllum, Podophyllum and Pachysandra were 8.4-10.6, 7.6-20.0, and 17.6-25.0 mya, respectively. However, the confidence ranges calculated using bootstrapping were much wider, at 3-19, 0-32 and 11-32 mya, respectively. Furthermore, deleting 10 adjacent taxa had a large effect in Pachysandra only, indicating that undersampling effects are significant among Buxales. Changes to sampling density in neighboring clades, or to the position of the fixed fossil calibration point had small to negligible effects. Non-parametric rate smoothing was more sensitive to taxon sampling effects than was penalized likelihood. The wide range for Podophyllum, compared to the other two genera, was probably due to a high degree of rate heterogeneity within this genus. Confidence ranges calculated by this method could be narrowed by sampling more individuals within the genus of interest, and by sequencing multiple DNA regions from all species in the phylogeny.展开更多
Protoplast electrofusion between callus protoplasts of cultivar TMS60444 and mesophyll protoplasts of cultivar SC8 was performed as an approach for the genetic improvement of cassava.The fusion products were subsequen...Protoplast electrofusion between callus protoplasts of cultivar TMS60444 and mesophyll protoplasts of cultivar SC8 was performed as an approach for the genetic improvement of cassava.The fusion products were subsequently cultured in protoplast culture medium(TM2 G) with gradual dilution for approximately 1-2 months.Then the protoplast-derived compact calli were transferred to suspension culture medium(SH) for suspension culture.The cultured products developed successively into embryos,mature embryos,and shoots on somatic embryo emerging medium(MSN),embryo maturation medium(CMM),and shoot elongation medium(CEM),respectively.And the shoots were then rooted on Murashige and Skoog(1962) medium(MS).Sixty-six cell lines were obtained and 12 of them developed into plantlets.Based on assessment of ploidy level and chromosome counting,four of these plantlets were tetraploid and the remaining eight were diploid.Based on assessment of ploidy level and simple sequence repeat(SSR) analysis,nine tetraploid cell lines,one diploid variant plant line and nine variant cell lines were obtained.The diploid variant plant line and the nine variant cell lines all showed partial loss of genetic material compared to that of the parent TMS60444,based on SSR patterns.These results showed that some new germplasm of cassava were created.In this study,a protocol for protoplast electrofusion was developed and validated.Another important conclusion from this work is the confirmation of a viable protocol for the regeneration of plants from cassava protoplasts.Going forward,we hope to provide technical guidance for cassava tissue culture,and also provide some useful inspiration and reference for further genetic improvement of cassava.展开更多
African leafy vegetables are becoming important crops in tackling nutrition and food security in many parts of sub-Saharan Africa, since they provide important micronutrients and vitamins, and help resource-poor farm ...African leafy vegetables are becoming important crops in tackling nutrition and food security in many parts of sub-Saharan Africa, since they provide important micronutrients and vitamins, and help resource-poor farm families bridge lean periods of food shortage. Genetic diversity studies are essential for crop improvement programmes as well as germplasm conservation efforts, and research on genetic diversity of these vegetables using molecular markers has been increasing over time. Diversity studies have evolved from the use of morphological and biochemical markers to molecular markers. Molecular markers provide valuable data, since they detect mostly selectively neutral variations at the DNA level. They are well established and their strengths and limitations have been described. New marker types are being developed from a combination of the strengths of the basic techniques to improve sensitivity, reproducibility, polymorphic information content, speed and cost. This review discusses the principles of some of the established molecular markers and their application to genetic diversity studies of African leafy vegetables with a main focus on the most common Solanum, Amaranthus, Cleome and Vigna species.展开更多
基金supported by grants from the Talent Program of Guangdong Academy of Sciences, China(2021GDASYL-20210103038, 2020GDASYL-2020102011,and 2021GDASYL-20210103036)the National Natural Science Foundation of China(32171292 and 32100294)+2 种基金the Guangdong Pearl River Talents Program, China(2021CX02N173)the China Postdoctoral Science Foundation(2020M682629)the Zhanjiang Plan for Navigation, China(211207157080997)。
文摘Soil salinity affects the expression of serine/arginine-rich(SR) genes and isoforms by alternative splicing, which in turn regulates the adaptation of plants to stress.We previously identified the cassava spliceosomal component 35 like(SCL) and SR subfamilies, belonging to the SR protein family, which are extensively involved in responses to abiotic stresses.However, the post-transcriptional regulatory mechanism of cassava arginine/serine-rich(RS) subfamily in response to salt stress remains to be explored.In the current study, we identified 37 genes of the RS subfamily from 11 plant species and systematically investigated the transcript levels of the RS40 and RS31 genes under diverse abiotic stress conditions.Subsequently, an analysis of the conserved protein domains revealed that plant RS subfamily genes were likely to preserve their conserved molecular functions and played critical functional roles in responses to abiotic stresses.Importantly, we found that overexpression of MeRS40 in Arabidopsis enhanced salt tolerance by maintaining reactive oxygen species homeostasis and up-regulating the salt-responsive genes.However,overexpression of MeRS40 gene in cassava reduced salt tolerance due to the depression of its endogenous gene expression by negative autoregulation of its own pre-mRNA.Moreover, the MeRS40 protein interacted with MeU1-70Ks(MeU1-70Ka and MeU1-70Kb) in vivo and in vitro, respectively.Therefore, our findings highlight the critical role of cassava SR proteins in responses to salt stress in plants.
基金supported by the National Natural Science Foundation of China(NSFC grant No.32171801 to S.L.)the Cross-Disciplinary Innovation Founding of Jilin University No.JLUXKJC2020313(S.L.).
文摘Tea is one of the most popular healthy and non-alcoholic beverages worldwide.Tea anthracnose is a disease in tea mature leaves and ultimately affects yield and quality.Colletotrichum camelliae is a dominant fungal pathogen in the tea field that infects tea plants in China.The pathogenic factors of fungus and the susceptible factors in the tea plant are not known.In this work,we performed molecular and genetic studies to observe a cerato-platanin protein CcCp1 from C.camelliae,which played a key role in fungal pathogenicity.CcCp1 mutants lost fungal virulence and reduced the ability to produce conidia.Transcriptome and metabolome were then performed and analysed in tea-susceptible and tea-resistant cultivars,Longjing 43 and Zhongcha 108,upon C.camelliae wild-type CCA andCcCp1 infection,respectively.The differentially expressed genes and the differentially accumulated metabolites in tea plants were clearly overrepresented such as linolenic acid and linoleic acid metabolism,glycerophospholipid metabolism,phenylalanine biosynthesis and metabolism,biosynthesis of f lavonoid,f lavone and f lavonol etc.In particular,the accumulation of jasmonic acid was significantly increased in the susceptible cultivar Longjing 43 upon CCA infection,in the fungal CcCp1 protein dependent manner,suggesting the compound involved in regulating fungal infection.In addition,other metabolites in the glycerophospholipid and phenylalanine pathway were observed in the resistant cultivar Zhongcha 108 upon fungal treatment,suggesting their potential role in defense response.Taken together,this work indicated C.camelliae CcCp1 affected the tea plant lipid metabolism pathway to promote disease while the lost function of CcCp1 mutants altered the fungal virulence and plant response.
文摘Salt stress is a major environmental stress that threats crop growth and yield.It is of great significance to study the molecular genetic network of plants in response to salt stress and to cultivate salt-tolerant crop varieties for national food security.A study published in Nature Plants,Dr.ZHAO Chunzhao’s group from the CAS Center for Excellence in Molecular Plant Sciences(CEMPS),Chinese Academy of Science,uncovers a novel mechanism underlying the coordination of plant growth and salt tolerance in plants.
基金funded by the National Natural Science Foundation of China(grants 41571054 and 31622015)the National Basic Research Program of China(grant 2014CB954100)+1 种基金Sichuan University(Fundamental Research Funds for the Central Universities,SCU2021D006 and SCU2022D003Institutional Research Funds,2021SCUNL102).
文摘Biogeographical barriers to gene flow are central to plant phylogeography.In East Asia,plant distribution is greatly influenced by two phylogeographic breaks,the Mekong-Salween Divide and Tanaka-Kaiyong Line,however,few studies have investigated how these barriers affect the genetic diversity of species that are distributed across both.Here we used 14 microsatellite loci and four chloroplast DNA fragments to examine genetic diversity and distribution patterns of 49 populations of Populus rotundifolia,a species that spans both the Mekong-Salween Divide and the Tanaka-Kaiyong Line in southwestern China.Demographic and migration hypotheses were tested using coalescent-based approaches.Limited historical gene flow was observed between the western and eastern groups of P.rotundifolia,but substantial flow occurred across both the Mekong-Salween Divide and Tanaka-Kaiyong Line,manifesting in clear admixture and high genetic diversity in the central group.Wind-borne pollen and seeds may have facilitated the dispersal of P.rotundifolia following prevalent northwest winds in the spring.We also found that the Hengduan Mountains,where multiple genetic barriers were detected,acted on the whole as a barrier between the western and eastern groups of P.rotundifolia.Ecological niche modeling suggested that P.rotundifolia has undergone range expansion since the last glacial maximum,and demographic reconstruction indicated an earlier population expansion around 600 Ka.The phylogeographic pattern of P.rotundifolia reflects the interplay of biological traits,wind patterns,barriers,niche differentiation,and Quaternary climate history.This study emphasizes the need for multiple lines of evidence in understanding the Quaternary evolution of plants in topographically complex areas.
基金This study was financially supported by National Natural Science Foundation of China(grant No.U20A2080,31622015)the Institutional Research Fund from Sichuan University(2021SCUNL102)Fundamental Research Fund for the Central Universities of China(SCU 2021D006,SCU 2022D003).
文摘Endangered species generally have small populations with low genetic diversity and a high genetic load.Thuja sutchuenensis is an endangered conifer endemic to southwestern China.It was once considered extinct in the wild,but in 1999 was rediscovered.However,little is known about its genetic load.We collected 67 individuals from five wild,isolated T.sutchuenensis populations,and used 636,151 SNPs to analyze the level of genetic diversity and genetic load in T.sutchuenensis to delineate the conservation units of T.sutchuenensis,based on whole transcriptome sequencing data,as well as target capture sequencing data.We found that populations of T.sutchuenensis could be divided into three groups.These groups had low levels genetic diversity and were moderately genetically differentiated.Our findings also indicate that T.sutchuenensis suffered two severe bottlenecks around the Last Glaciation Period and Last Glacial Maximum.Among Thuja species,T.sutchuenensis presented the lowest genetic load and hence might have purged deleterious mutations efficiently through purifying selection.However,distribution of fitness effects analysis indicated a high extinction risk for T.sutchuenensis.Multiple lines of evidence identified three management units for T.sutchuenensis.Although T.sutchuenensis possesses a low genetic load,low genetic diversity,suboptimal fitness,and anthropogenic pressures all present an extinction risk for this rare conifer.This might also hold true for many endangered plant species in the mountains all over the world.
基金supported by the Guangdong Basic and Applied Basic Research Foundation(2020A1515111101,2022A1515110431).
文摘Plasma membrane intrinsic proteins(PIPs)are conserved plant aquaporins that transport small molecules across the plasma membrane to trigger instant stress responses and maintain cellular homeostasis under biotic and abiotic stress.To elucidate their roles in plant immunity to pathogen attack,we characterized the expression patterns,subcellular localizations,and H_(2)O_(2)-transport ability of 11 OsPIPs in rice(Oryza sativa),and identified OsPIP2;6 as necessary for rice disease resistance.OsPIP2;6 resides on the plasma membrane and facilitates cytoplasmic import of the immune signaling molecule H_(2)O_(2).Knockout of OsPIP2;6 increases rice susceptibility to Magnaporthe oryzae,indicating a positive function in plant immunity.OsPIP2;6 interacts with OsPIP2;2,which has been reported to increase rice resistance to pathogens via H_(2)O_(2)transport.Our findings suggest that OsPIP2;6 cooperates with OsPIP2;2 as a defense signal transporter complex during plant–pathogen interaction.
基金supported by the National Natural Science Foundation of China (31171805 and 31371897)
文摘The mitogen-activated protein kinase (MAPK), a key signal transduction component in the MAPK cascade pathway, regulates a variety of physiological activities in eukaryotes. However, little is known of the role MAPK plays in phytopathogenic fungi. In this research, we cloned the MAPK gene STK1 from the northern corn leaf blight pathogen Setosphaeria turcica and found that the gene shared high homology with the high osmolality glycerol (HOG) MAPK gene HOG1 of Saccharomy- ces cerevisiae. In addition, gene knockout technology was employed to investigate the function of STKI. Gene knockout mutants (KOs) were found to have altered hyphae morphology and no conidiogenesis, though they did show similar radial growth rate compared to the wild-type strain (WT). Furthermore, microscope observations indicated that STK1 KOs did not form normal appressoria at 48 h post-inoculation on a hydrophobic surface. STK1 KOs had reduced virulence, a significantly altered Helminthosporium turcicum (HT)-toxin composition, and diminished pathogenicity on the leaves of susceptible inbred corn OH43. Mycelium morphology appeared to be significantly swollen and the radial growth rates of STK1 KOs declined in comparison with WT under high osmotic stress. These results suggested that STK1 affects the hyphae development, conidiogenesis, and pathogenicity of S. turcica by regulating appressorium development and HT-toxin biosynthesis. Moreover, the gene appears to be involved in the hypertonic stress response in S. turcica.
基金the National Key Research and Development Program of China(2018YFD1000601)the Key Research and Development(R&D)Program of Anhui Province(18030701155)+1 种基金Funding from Anhui Agricultural University,and Funding from the State Key Laboratory of Tea Plant Biology and UtilizationThe Postgraduate Foundation of Anhui Agricultural University,Anhui Province,China(2020ysj-33).
文摘Under high light conditions or UV radiation,tea plant leaves produce more flavonols,which contribute to the bitter taste of tea;however,neither the flavonol biosynthesis pathways nor the regulation of their production are well understood.Intriguingly,tea leaf flavonols are enhanced by UV-B but reduced by shading treatment.CsFLS,CsUGT78A14,CsMYB12,and CsbZIP1 were upregulated by UV-B radiation and downregulated by shading.CsMYB12 and CsbZIP1 bound to the promoters of CsFLS and CsUGT78A14,respectively,and activated their expression individually.CsbZIP1 positively regulated CsMYB12 and interacted with CsMYB12,which specifically activated flavonol biosynthesis.Meanwhile,CsPIF3 and two MYB repressor genes,CsMYB4 and CsMYB7,displayed expression patterns opposite to that of CsMYB12.CsMYB4 and CsMYB7 bound to CsFLS and CsUGT78A14 and repressed their CsMYB12-activated expression.While CsbZIP1 and CsMYB12 regulated neither CsMYB4 nor CsMYB7,CsMYB12 interacted with CsbZIP1,CsMYB4,and CsMYB7,but CsbZIP1 did not physically interact with CsMYB4 or CsMYB7.Finally,CsPIF3 bound to and activated CsMYB7 under shading to repress flavonol biosynthesis.These combined results suggest that UV activation and shading repression of flavonol biosynthesis in tea leaves are coordinated through a complex network involving CsbZIP1 and CsPIF3 as positive MYB activators and negative MYB repressors,respectively.The study thus provides insight into the regulatory mechanism underlying the production of bitter-tasting flavonols in tea plants.
基金supported by the National Natural Science Foundation of China(31630052,31788103)Chinese Academy of Sciences(XDB27010104,QYZDYSSW-SMC023,159231KYSB20200008)+1 种基金the National Key Research and Development Program of China(2016YFD0100604)the Shanghai Science and Technology Development(18JC1415000)。
文摘Global warming threatens food security.Rice(Oryza sativa L.),a vital food crop,is vulnerable to heat stress,especially at the reproductive stage.Here we summarize putative mechanisms of high-temperature perception(via RNA secondary structure,the phyB gene,and phase separation)and response(membrane fluidity,heat shock factors,heat shock proteins,and ROS(reactive oxygen species)scavenging)in plants.We describe how rice responds to heat stress at different cell-component levels(membrane,endoplasmic reticulum,chloroplasts,and mitochondria)and functional levels(denatured protein elimination,ROS scavenging,stabilization of DNA and RNA,translation,and metabolic flux changes).We list temperature-sensitive genetic male sterility loci available for use in rice hybrid breeding and explain the regulatory mechanisms associated with some of them.Breeding thermotolerant rice species without yield penalties via natural alleles mining and transgenic editing should be the focus of future work.
基金NERC (fellowship NE/B500658/1) for the financial support that made this work possible
文摘A universal method of molecular dating that can be applied to all families and genera regardless of their fossil records, or lack thereof, is highly desirable. A possible method for eudicots is to use a large phylogeny calibrated using deep fossils including tricolpate pollen as a fixed (124 mya) calibration point. This method was used to calculate node ages within three species-poor disjunct basal eudicot genera, Caulophyllum, Podophyllum and Pachysandra, and sensitivity of these ages to effects such as taxon sampling were then quantified. By deleting from one to three accessions related to each genus in 112 different combinations, a confidence range describing variation due only to taxon sampling was generated. Ranges for Caulophyllum, Podophyllum and Pachysandra were 8.4-10.6, 7.6-20.0, and 17.6-25.0 mya, respectively. However, the confidence ranges calculated using bootstrapping were much wider, at 3-19, 0-32 and 11-32 mya, respectively. Furthermore, deleting 10 adjacent taxa had a large effect in Pachysandra only, indicating that undersampling effects are significant among Buxales. Changes to sampling density in neighboring clades, or to the position of the fixed fossil calibration point had small to negligible effects. Non-parametric rate smoothing was more sensitive to taxon sampling effects than was penalized likelihood. The wide range for Podophyllum, compared to the other two genera, was probably due to a high degree of rate heterogeneity within this genus. Confidence ranges calculated by this method could be narrowed by sampling more individuals within the genus of interest, and by sequencing multiple DNA regions from all species in the phylogeny.
基金financially supported by the National Natural Science Foundation of China(31401438)the Innovation Research Team of the Ministry of Education of China(IRT_17R45)+1 种基金the earmarked fund for China Agriculture Research System(CARS-11-GXLJ)the Guangxi Scientific and Technological Development Subject,China(AB16380080 and AB16380163)
文摘Protoplast electrofusion between callus protoplasts of cultivar TMS60444 and mesophyll protoplasts of cultivar SC8 was performed as an approach for the genetic improvement of cassava.The fusion products were subsequently cultured in protoplast culture medium(TM2 G) with gradual dilution for approximately 1-2 months.Then the protoplast-derived compact calli were transferred to suspension culture medium(SH) for suspension culture.The cultured products developed successively into embryos,mature embryos,and shoots on somatic embryo emerging medium(MSN),embryo maturation medium(CMM),and shoot elongation medium(CEM),respectively.And the shoots were then rooted on Murashige and Skoog(1962) medium(MS).Sixty-six cell lines were obtained and 12 of them developed into plantlets.Based on assessment of ploidy level and chromosome counting,four of these plantlets were tetraploid and the remaining eight were diploid.Based on assessment of ploidy level and simple sequence repeat(SSR) analysis,nine tetraploid cell lines,one diploid variant plant line and nine variant cell lines were obtained.The diploid variant plant line and the nine variant cell lines all showed partial loss of genetic material compared to that of the parent TMS60444,based on SSR patterns.These results showed that some new germplasm of cassava were created.In this study,a protocol for protoplast electrofusion was developed and validated.Another important conclusion from this work is the confirmation of a viable protocol for the regeneration of plants from cassava protoplasts.Going forward,we hope to provide technical guidance for cassava tissue culture,and also provide some useful inspiration and reference for further genetic improvement of cassava.
文摘African leafy vegetables are becoming important crops in tackling nutrition and food security in many parts of sub-Saharan Africa, since they provide important micronutrients and vitamins, and help resource-poor farm families bridge lean periods of food shortage. Genetic diversity studies are essential for crop improvement programmes as well as germplasm conservation efforts, and research on genetic diversity of these vegetables using molecular markers has been increasing over time. Diversity studies have evolved from the use of morphological and biochemical markers to molecular markers. Molecular markers provide valuable data, since they detect mostly selectively neutral variations at the DNA level. They are well established and their strengths and limitations have been described. New marker types are being developed from a combination of the strengths of the basic techniques to improve sensitivity, reproducibility, polymorphic information content, speed and cost. This review discusses the principles of some of the established molecular markers and their application to genetic diversity studies of African leafy vegetables with a main focus on the most common Solanum, Amaranthus, Cleome and Vigna species.