Drought is a major environmental factor limiting wheat production worldwide,and developing drought-tolerant cultivars is a central challenge for wheat breeders globally.Therefore,it is important to identify genetic co...Drought is a major environmental factor limiting wheat production worldwide,and developing drought-tolerant cultivars is a central challenge for wheat breeders globally.Therefore,it is important to identify genetic components determining drought tolerance in wheat.In this study,we identified a wheat NAC gene(TaNAC071-A)that is tightly associated with drought tolerance by a genome-wide association study.Knockdown of TaNAC071-A in wheat attenuated plant drought tolerance,whereas its overexpression significantly enhanced drought tolerance through improved water-use efficiency and increased expression of stress-responsive genes.This heightened water-saving mechanism mitigated the yield loss caused by water deficit.Further candidate gene association analysis showed that a 108-bp insertion in the promoter of TaNAC071-A alters its expression level and contributes to variation in drought tolerance among wheat accessions.This insertion contains two MYB cis-regulatory elements(CREs)that can be directly bound by the MYB transcription activator,TaMYBL1,thereby leading to increased TaNAC071-A expression and plant drought tolerance.Importantly,introgression of this 108-bp insertion allele,TaNAC071-AIn-693,into drought-sensitive cultivars could improve their drought tolerance,demonstrating that it is a valuable genetic resource for wheat breeding.Taken together,our findings highlight a major breakthrough in determining the genetic basis underlying phenotypic variation in wheat drought tolerance and showcase the potential of exploiting CRE-containing indels for improving important agronomical traits.展开更多
A subfamily of four Phytochrome （phy）-Interacting bHLH transcription Factors （PIFs） collectively promote skotomorphogenic development in dark-grown seedlings. This activity is reversed upon exposure to light, by p...A subfamily of four Phytochrome （phy）-Interacting bHLH transcription Factors （PIFs） collectively promote skotomorphogenic development in dark-grown seedlings. This activity is reversed upon exposure to light, by photoacti- vated phy molecules that induce degradation of the PIFs, thereby triggering the transcriptional changes that drive a tran- sition to photomorphogenesis. The PIFs function both redundantly and partially differentially at the morphogenic level in this process, To identify the direct targets of PIF transcriptional regulation genome-wide, we analyzed the DNA-binding sites for all four PIFs by ChlP-seq analysis, and defined the genes transcriptionally regulated by each PIF, using RNA-seq analysis of pif mutants. Despite the absence of detectable differences in DNA-binding-motif recognition between the PIFs, the data show a spectrum of regulatory patterns, ranging from single PIF dominance to equal contributions by all four. Similarly, a broad array of promoter architectures was found, ranging from single PIF-binding sites, containing single sequence motifs, through multiple PIF-binding sites, each containing one or more motifs, with each site occupied prefer- entially by one to multiple PIFs. Quantitative analysis of the promoter occupancy and expression level induced by each PIF revealed an intriguing pattern. Although there is no robust correlation broadly across the target-gene population, examination of individual genes that are shared targets of multiple PIFs shows a gradation in correlation from strongly positive, through uncorrelated, to negative. This finding suggests a dual-layered mechanism of transcriptional regulation, comprising both a continuum of binding-site occupancy by each PIF and a superimposed layer of local regulation that acts differentially on each PIF, to modulate its intrinsic transcriptional activation capacity at each site, in a quantitative pattern that varies between the individual PIFs from gene to gene. These findings provide a framework for probing the mecha- nisms by which transcription factors with overlapping direct-target genes integrate and selectively transduce signals to their target networks.展开更多
基金supported by grants from the National Natural Science Foundation of China(31701418 and 32072002)the Natural Science Basic Research Plan in Shaanxi Province of China(2019JCW-18)and the 111 Project from the Ministry of Education of China(B07049).
文摘Drought is a major environmental factor limiting wheat production worldwide,and developing drought-tolerant cultivars is a central challenge for wheat breeders globally.Therefore,it is important to identify genetic components determining drought tolerance in wheat.In this study,we identified a wheat NAC gene(TaNAC071-A)that is tightly associated with drought tolerance by a genome-wide association study.Knockdown of TaNAC071-A in wheat attenuated plant drought tolerance,whereas its overexpression significantly enhanced drought tolerance through improved water-use efficiency and increased expression of stress-responsive genes.This heightened water-saving mechanism mitigated the yield loss caused by water deficit.Further candidate gene association analysis showed that a 108-bp insertion in the promoter of TaNAC071-A alters its expression level and contributes to variation in drought tolerance among wheat accessions.This insertion contains two MYB cis-regulatory elements(CREs)that can be directly bound by the MYB transcription activator,TaMYBL1,thereby leading to increased TaNAC071-A expression and plant drought tolerance.Importantly,introgression of this 108-bp insertion allele,TaNAC071-AIn-693,into drought-sensitive cultivars could improve their drought tolerance,demonstrating that it is a valuable genetic resource for wheat breeding.Taken together,our findings highlight a major breakthrough in determining the genetic basis underlying phenotypic variation in wheat drought tolerance and showcase the potential of exploiting CRE-containing indels for improving important agronomical traits.
文摘A subfamily of four Phytochrome （phy）-Interacting bHLH transcription Factors （PIFs） collectively promote skotomorphogenic development in dark-grown seedlings. This activity is reversed upon exposure to light, by photoacti- vated phy molecules that induce degradation of the PIFs, thereby triggering the transcriptional changes that drive a tran- sition to photomorphogenesis. The PIFs function both redundantly and partially differentially at the morphogenic level in this process, To identify the direct targets of PIF transcriptional regulation genome-wide, we analyzed the DNA-binding sites for all four PIFs by ChlP-seq analysis, and defined the genes transcriptionally regulated by each PIF, using RNA-seq analysis of pif mutants. Despite the absence of detectable differences in DNA-binding-motif recognition between the PIFs, the data show a spectrum of regulatory patterns, ranging from single PIF dominance to equal contributions by all four. Similarly, a broad array of promoter architectures was found, ranging from single PIF-binding sites, containing single sequence motifs, through multiple PIF-binding sites, each containing one or more motifs, with each site occupied prefer- entially by one to multiple PIFs. Quantitative analysis of the promoter occupancy and expression level induced by each PIF revealed an intriguing pattern. Although there is no robust correlation broadly across the target-gene population, examination of individual genes that are shared targets of multiple PIFs shows a gradation in correlation from strongly positive, through uncorrelated, to negative. This finding suggests a dual-layered mechanism of transcriptional regulation, comprising both a continuum of binding-site occupancy by each PIF and a superimposed layer of local regulation that acts differentially on each PIF, to modulate its intrinsic transcriptional activation capacity at each site, in a quantitative pattern that varies between the individual PIFs from gene to gene. These findings provide a framework for probing the mecha- nisms by which transcription factors with overlapping direct-target genes integrate and selectively transduce signals to their target networks.
