Heat stress is a major threat to maize(Zea mays L.)production worldwide.Heat shock transcription factors(HSFs)play vital roles in plant responses to heat stress.However,the molecular and genetic mechanisms underlying ...Heat stress is a major threat to maize(Zea mays L.)production worldwide.Heat shock transcription factors(HSFs)play vital roles in plant responses to heat stress.However,the molecular and genetic mechanisms underlying HSF-meditated thermotolerance in maize remain largely unexplored.In this study,we demonstrate that the alternative splicing of ZmHsf23 modulates heat stress tolerance in maize.Hsf23 produced two functional transcripts,Hsf23L and Hsf23S,which differ by the presence of a cryptic mini-exon in Hsf23L that is spliced out in Hsf23S.Both transcripts were strongly induced by heat stress.Mutants lacking Hsf23L alone(hsf23l)or both Hsf23L and Hsf23S(hsf23l23s)exhibited increased susceptibility to heat stress,whereas overexpression of Hsf23S enhanced heat stress tolerance in maize.Subsequently,we found that Hsf23S positively regulates heat stress tolerance by directly activating the transcription of three sHSP genes(Hsp16.9,Hsp17.2,and Hsp18a)and TIL1 gene.In addition,Hsf23L physically interacted with Hsf23S and enhanced the transcriptional activation of Hsf23S on the sHSPs and TIL1 promoters.Notably,genetic analysis suggested that co-overexpression of Hsf23L and Hsf23S further improves heat tolerance of the transgenic plants.Taken together,these results reveal two splicing variants of ZmHsf23 cooperatively regulate maize heat tolerance,thus highlighting potential value of ZmHsf23 in breeding heat-tolerant maize varieties.展开更多
GTs(Glycosyltransferases)are important in plant growth and abiotic stresses.However,its role in maize heat response is far from clear.Here,we describe the constitutively expressed UDP-glycosyltransferase ZmUGT92A1,whi...GTs(Glycosyltransferases)are important in plant growth and abiotic stresses.However,its role in maize heat response is far from clear.Here,we describe the constitutively expressed UDP-glycosyltransferase ZmUGT92A1,which has a highly conserved PSPG box and is localized in chloroplasts,is induced under heat stress.Functional disruption of ZmUGT92A1 leads to heat sensitivity and reactive oxygen species accumulation in maize.Metabolomics analysis revealed that ZmUGT92A1 affected multiple metabolic pathways and altered the metabolic homeostasis of flavonoids under heat stress.In vitro assay showed ZmUGT92A1 exhibits glycosyltransferase activity on flavonoids and hormones.Additionally,we identified a rapidly heat-induced transcription factor,ZmHSF08,which can directly bind and repress the promoter region of ZmUGT92A1.The ZmHSF08 overexpression line exhibits heat sensitivity and reactive oxygen species accumulation.These findings reveal that the ZmHSF08-ZmUGT92A1 module plays a role in heat tolerance in maize and provide candidate strategies for the development of heat-tolerant varieties.展开更多
The male sterility(MS)line is a prerequisite for efficient production of hybrid seeds in rice,a self-pollinating species.MS line breeding is pivotal for hybrid rice improvement.Understanding the historical breeding tr...The male sterility(MS)line is a prerequisite for efficient production of hybrid seeds in rice,a self-pollinating species.MS line breeding is pivotal for hybrid rice improvement.Understanding the historical breeding tra-jectory will help to improve hybrid rice breeding strategies.Maternally inherited cytoplasm is an appro-priate tool for phylogenetic reconstruction and pedigree tracing in rice hybrids.In this study,we analyzed the cytoplasmic genomes of 1495 elite hybrid rice varieties and identified five major types of cytoplasm,which correspond to different hybrid production systems.As the cytoplasm donors for hybrids,461 MS lines were also divided into five major types based on cytoplasmic and nuclear genomic architecture.Spe-cific core accessions cooperating with different fertility-associated genes drove the sequence divergence of MS lines.Dozens to hundreds of convergent and divergent selective sweeps spanning several agro-nomic trait-associated genes were identified among different types of MS lines.We further analyzed the cross patterns between different types of MS lines and their corresponding restorers.This study system-atically analyzed the cytoplasmic genomes of rice hybrids revealed their relationships with nuclear ge-nomes of MS lines,and illustrated the trajectory of hybrid rice breeding and the strategies for breeding different types of MS lines providing new insights for future improvement of hybrid rice.展开更多
基金supported by the National Key Research and Development Program of China(2021YFF1000301)the National Natural Science Foundation of China(31771805)。
文摘Heat stress is a major threat to maize(Zea mays L.)production worldwide.Heat shock transcription factors(HSFs)play vital roles in plant responses to heat stress.However,the molecular and genetic mechanisms underlying HSF-meditated thermotolerance in maize remain largely unexplored.In this study,we demonstrate that the alternative splicing of ZmHsf23 modulates heat stress tolerance in maize.Hsf23 produced two functional transcripts,Hsf23L and Hsf23S,which differ by the presence of a cryptic mini-exon in Hsf23L that is spliced out in Hsf23S.Both transcripts were strongly induced by heat stress.Mutants lacking Hsf23L alone(hsf23l)or both Hsf23L and Hsf23S(hsf23l23s)exhibited increased susceptibility to heat stress,whereas overexpression of Hsf23S enhanced heat stress tolerance in maize.Subsequently,we found that Hsf23S positively regulates heat stress tolerance by directly activating the transcription of three sHSP genes(Hsp16.9,Hsp17.2,and Hsp18a)and TIL1 gene.In addition,Hsf23L physically interacted with Hsf23S and enhanced the transcriptional activation of Hsf23S on the sHSPs and TIL1 promoters.Notably,genetic analysis suggested that co-overexpression of Hsf23L and Hsf23S further improves heat tolerance of the transgenic plants.Taken together,these results reveal two splicing variants of ZmHsf23 cooperatively regulate maize heat tolerance,thus highlighting potential value of ZmHsf23 in breeding heat-tolerant maize varieties.
基金supported by the National Key Research and Development Program of China (2021YFF1000301)the National Natural Science Foundation of China (31771805)。
文摘GTs(Glycosyltransferases)are important in plant growth and abiotic stresses.However,its role in maize heat response is far from clear.Here,we describe the constitutively expressed UDP-glycosyltransferase ZmUGT92A1,which has a highly conserved PSPG box and is localized in chloroplasts,is induced under heat stress.Functional disruption of ZmUGT92A1 leads to heat sensitivity and reactive oxygen species accumulation in maize.Metabolomics analysis revealed that ZmUGT92A1 affected multiple metabolic pathways and altered the metabolic homeostasis of flavonoids under heat stress.In vitro assay showed ZmUGT92A1 exhibits glycosyltransferase activity on flavonoids and hormones.Additionally,we identified a rapidly heat-induced transcription factor,ZmHSF08,which can directly bind and repress the promoter region of ZmUGT92A1.The ZmHSF08 overexpression line exhibits heat sensitivity and reactive oxygen species accumulation.These findings reveal that the ZmHSF08-ZmUGT92A1 module plays a role in heat tolerance in maize and provide candidate strategies for the development of heat-tolerant varieties.
基金supported by grants from the National Natural Science Foundation of China(31788103)the Chinese Academy of Sciences(XDB27010301).
文摘The male sterility(MS)line is a prerequisite for efficient production of hybrid seeds in rice,a self-pollinating species.MS line breeding is pivotal for hybrid rice improvement.Understanding the historical breeding tra-jectory will help to improve hybrid rice breeding strategies.Maternally inherited cytoplasm is an appro-priate tool for phylogenetic reconstruction and pedigree tracing in rice hybrids.In this study,we analyzed the cytoplasmic genomes of 1495 elite hybrid rice varieties and identified five major types of cytoplasm,which correspond to different hybrid production systems.As the cytoplasm donors for hybrids,461 MS lines were also divided into five major types based on cytoplasmic and nuclear genomic architecture.Spe-cific core accessions cooperating with different fertility-associated genes drove the sequence divergence of MS lines.Dozens to hundreds of convergent and divergent selective sweeps spanning several agro-nomic trait-associated genes were identified among different types of MS lines.We further analyzed the cross patterns between different types of MS lines and their corresponding restorers.This study system-atically analyzed the cytoplasmic genomes of rice hybrids revealed their relationships with nuclear ge-nomes of MS lines,and illustrated the trajectory of hybrid rice breeding and the strategies for breeding different types of MS lines providing new insights for future improvement of hybrid rice.
