Plants initiate leaf senescence to reallocate energy and nutrients from aging to developing tissues for optimizing growth fitness and reproduction at the end of the growing season or under stress. Jasmonate （JA）, a ...Plants initiate leaf senescence to reallocate energy and nutrients from aging to developing tissues for optimizing growth fitness and reproduction at the end of the growing season or under stress. Jasmonate （JA）, a lipid-derived phytohormone, is known as an important endogenous signal in inducing leaf senescence. However, whether and how the circadian clock gates JA signaling to induce leaf senescence in plants remains elusive. In this study, we show that Evening Complex （EC）, a core component of the circadian oscillator, negatively regulates leaf senescence in Arabidopsis thaliana. Transcriptomic profiling analysis reveals that EC is closely involved in JA signaling and response, consistent with accelerated leaf senescence unanimously displayed by EC mutants upon JA induction. We found that EC directly binds the promoter of MYC2, which encodes a key activator of JA-induced leaf senescence, and represses its expression. Ge- netic analysis further demonstrated that the accelerated JA-induced leaf senescence in EC mutants is abrogated by myc2 myc3 myc4 triple mutation. Collectively, these results reveal a critical molecular mechanism illustrating how the core component of the circadian clock gates JA signaling to regulate leaf senescence.展开更多
Soybean,a typical short-day crop,is sensitive to photoperiod,which is a major limiting factor defining its north-to-south cultivation range.The long-juvenile(LJ)trait is controlled primarily by the J locus which has b...Soybean,a typical short-day crop,is sensitive to photoperiod,which is a major limiting factor defining its north-to-south cultivation range.The long-juvenile(LJ)trait is controlled primarily by the J locus which has been used for decades by soybean breeders to delay flowering and improve grain yield in tropical regions.The J gene encodes an ortholog of the Arabidopsis Evening Complex(EC)component EARLY FLOWERING 3(ELF3).To identify modifiers of J,we conducted a forward genetic screen and isolated a mutant(eoj57)that in combination with j has longer flowering delay compared with j single mutant plants.Map-based cloning and genome re-sequencing identified eoj57(designated as GmLUX2)as an ortholog of the Arabidopsis EC component LUX ARRHYTHMO(LUX).To validate that GmLUX2 is a modifier of J,we used trans-complementation and identified a natural variant allele with a similar phenotype.We also show that GmLUX2 physically interacts with GmELF3a/b and binds DNA,whereas the mutant and natural variant are attenuated in both activities.Transcriptome analysis shows that the GmLUX2-GmELF3a complex co-regulates the expression of several circadian clock-associated genes and directly represses E1 expression.These results provide mechanistic insight into how GmLUX2-GmELF3 controls flowering time via synergistic regulation of gene expression.These novel insights expand our understanding of the regulation of the EC complex,and facilitate the development of soybean varieties adapted for growth at lower latitudes.展开更多
The circadian clock entrained by environmental light-dark cycles enables plants to fine-tune diurnal growth and developmental responses.Here,we show that physical interactions among evening clock components,including ...The circadian clock entrained by environmental light-dark cycles enables plants to fine-tune diurnal growth and developmental responses.Here,we show that physical interactions among evening clock components,including PSEUDO-RESPONSE REGULATOR 5(PRR5),TIMING OF CAB EXPRESSION 1(TOC1),and the Evening Complex(EC)component EARLY FLOWERING 3(ELF3),define a diurnal repressive chromatin structure specifically at the PHYTOCHROME-INTERACTING FACTOR 4(PIF4)locus in Arabidopsis.These three clock components act interdependently as well as independently to repress nighttime hypocotyl elongation,as hypocotyl elongation rate dramatically increased specifically at nighttime in the prr5-1 toc1-21 elf3-1 mutant,concomitantly with a substantial increase in PIF4 expression.Transcriptional repression of PIF4 by ELF3,PRR5,and TOC1 is mediated by the SWI2/SNF2-RELATED(SWR1)chromatin remodeling complex,which incorporates histone H2A.Z at thePIF4 locus,facilitating robust epigenetic suppression ofPIF4 during the evening.Overall,these findings demonstrate that the PRR-EC-SWR1 complex represses hypocotyl elongation at night through a distinctive chromatin domain covering PIF4 chromatin.展开更多
In plants,the photoperiod sensitivity directly influences flowering time,which in turn affects latitudinal adaptation and yield.However,research into the mechanisms underlying photoperiod sensitivity,particularly thos...In plants,the photoperiod sensitivity directly influences flowering time,which in turn affects latitudinal adaptation and yield.However,research into the mechanisms underlying photoperiod sensitivity,particularly those mediated by epigenetic regulation,is still in its nascent stages.In this study,we analyzed the regulation of photoperiod sensitivity in Arabidopsis thaliana.We demonstrate that the evening complex LUX ARRYTHMO(LUX)and the chromatin remodeling factor SWITCH/SUCROSE NONFERMENTING 3C(SWI3C)regulate GI locus chromatin compaction and H3K4me3 modification levels at the GIGANTEA locus under different photoperiod conditions.This mechanism is one of the key factors that allow plants to distinguish between long-day and short-day photoperiods.Our study provides insight into how the LUX–SWI3C module regulates photoperiod sensitivity at the epigenetic level.展开更多
Circadian clocks are endogenous timers that enable plants to synchronize biological processes with daily and seasonal environmental conditions in order to allocate resources during the most beneficial times of day and...Circadian clocks are endogenous timers that enable plants to synchronize biological processes with daily and seasonal environmental conditions in order to allocate resources during the most beneficial times of day and year. The circadian clock regulates a number of central plant activities, including growth, develop- ment, and reproduction, primarily through controlling a substantial proportion of transcriptional activity and protein function. This review examines the roles that alleles of circadian clock genes have played in domestication and improvement of crop plants. The focus here is on three groups of circadian clock genes essential to clock function in Arabidopsis thaliana： PSEUDO-RESPONSE REGULATORs, GIGANTEA, and the evening complex genes EARL Y FLOWERING 3, EARLY FLOWERING 4, and LUX ARRHYTHMO. Homol- ogous genes from each group underlie quantitative trait loci that have beneficial influences on key agricul- tural traits, especially flowering time but also yield, biomass, and biennial growth habit. Emerging insights into circadian clock regulation of other fundamental plant processes, including responses to abiotic and biotic stresses, are discussed to highlight promising avenues for further crop improvement.展开更多
文摘Plants initiate leaf senescence to reallocate energy and nutrients from aging to developing tissues for optimizing growth fitness and reproduction at the end of the growing season or under stress. Jasmonate （JA）, a lipid-derived phytohormone, is known as an important endogenous signal in inducing leaf senescence. However, whether and how the circadian clock gates JA signaling to induce leaf senescence in plants remains elusive. In this study, we show that Evening Complex （EC）, a core component of the circadian oscillator, negatively regulates leaf senescence in Arabidopsis thaliana. Transcriptomic profiling analysis reveals that EC is closely involved in JA signaling and response, consistent with accelerated leaf senescence unanimously displayed by EC mutants upon JA induction. We found that EC directly binds the promoter of MYC2, which encodes a key activator of JA-induced leaf senescence, and represses its expression. Ge- netic analysis further demonstrated that the accelerated JA-induced leaf senescence in EC mutants is abrogated by myc2 myc3 myc4 triple mutation. Collectively, these results reveal a critical molecular mechanism illustrating how the core component of the circadian clock gates JA signaling to regulate leaf senescence.
基金supported by grants from the National Key Research and Development Program of China(2016YFD0101900)National Natural Science Foundation of China(31271745)to C.Y.the National Key Project for Research on Transgenic Biology in China(2014ZX0800921B)to Y.W.
文摘Soybean,a typical short-day crop,is sensitive to photoperiod,which is a major limiting factor defining its north-to-south cultivation range.The long-juvenile(LJ)trait is controlled primarily by the J locus which has been used for decades by soybean breeders to delay flowering and improve grain yield in tropical regions.The J gene encodes an ortholog of the Arabidopsis Evening Complex(EC)component EARLY FLOWERING 3(ELF3).To identify modifiers of J,we conducted a forward genetic screen and isolated a mutant(eoj57)that in combination with j has longer flowering delay compared with j single mutant plants.Map-based cloning and genome re-sequencing identified eoj57(designated as GmLUX2)as an ortholog of the Arabidopsis EC component LUX ARRHYTHMO(LUX).To validate that GmLUX2 is a modifier of J,we used trans-complementation and identified a natural variant allele with a similar phenotype.We also show that GmLUX2 physically interacts with GmELF3a/b and binds DNA,whereas the mutant and natural variant are attenuated in both activities.Transcriptome analysis shows that the GmLUX2-GmELF3a complex co-regulates the expression of several circadian clock-associated genes and directly represses E1 expression.These results provide mechanistic insight into how GmLUX2-GmELF3 controls flowering time via synergistic regulation of gene expression.These novel insights expand our understanding of the regulation of the EC complex,and facilitate the development of soybean varieties adapted for growth at lower latitudes.
基金supported by the Basic Science Research(NRF2022R1A2B5B02001266 to P.J.S.and NRF-2023R1A2C3002386 to E.O.)Basic Research Laboratory(NRF-2022R1A4A3024451)programs provided by the National Research Foundation of Korea.
文摘The circadian clock entrained by environmental light-dark cycles enables plants to fine-tune diurnal growth and developmental responses.Here,we show that physical interactions among evening clock components,including PSEUDO-RESPONSE REGULATOR 5(PRR5),TIMING OF CAB EXPRESSION 1(TOC1),and the Evening Complex(EC)component EARLY FLOWERING 3(ELF3),define a diurnal repressive chromatin structure specifically at the PHYTOCHROME-INTERACTING FACTOR 4(PIF4)locus in Arabidopsis.These three clock components act interdependently as well as independently to repress nighttime hypocotyl elongation,as hypocotyl elongation rate dramatically increased specifically at nighttime in the prr5-1 toc1-21 elf3-1 mutant,concomitantly with a substantial increase in PIF4 expression.Transcriptional repression of PIF4 by ELF3,PRR5,and TOC1 is mediated by the SWI2/SNF2-RELATED(SWR1)chromatin remodeling complex,which incorporates histone H2A.Z at thePIF4 locus,facilitating robust epigenetic suppression ofPIF4 during the evening.Overall,these findings demonstrate that the PRR-EC-SWR1 complex represses hypocotyl elongation at night through a distinctive chromatin domain covering PIF4 chromatin.
基金supported by the Joint Funding Project of Guangzhou Municipal Government,Universities(Academies)and Enterprises(2023A03J0049 to F.K.)the Open Competition Program of Top Ten Critical Priorities of Agricultural Science and Technology Innovation for the 14th Five-Year Plan of Guangdong Province(2022SDZG05 to F.K.and B.L.)the National Natural Science Foundation of China(32090064 to F.K.,32301824to J.W.,32401857to Z.S.,32201866 to F.W.,and 32301823 to Hu.L.).
文摘In plants,the photoperiod sensitivity directly influences flowering time,which in turn affects latitudinal adaptation and yield.However,research into the mechanisms underlying photoperiod sensitivity,particularly those mediated by epigenetic regulation,is still in its nascent stages.In this study,we analyzed the regulation of photoperiod sensitivity in Arabidopsis thaliana.We demonstrate that the evening complex LUX ARRYTHMO(LUX)and the chromatin remodeling factor SWITCH/SUCROSE NONFERMENTING 3C(SWI3C)regulate GI locus chromatin compaction and H3K4me3 modification levels at the GIGANTEA locus under different photoperiod conditions.This mechanism is one of the key factors that allow plants to distinguish between long-day and short-day photoperiods.Our study provides insight into how the LUX–SWI3C module regulates photoperiod sensitivity at the epigenetic level.
文摘Circadian clocks are endogenous timers that enable plants to synchronize biological processes with daily and seasonal environmental conditions in order to allocate resources during the most beneficial times of day and year. The circadian clock regulates a number of central plant activities, including growth, develop- ment, and reproduction, primarily through controlling a substantial proportion of transcriptional activity and protein function. This review examines the roles that alleles of circadian clock genes have played in domestication and improvement of crop plants. The focus here is on three groups of circadian clock genes essential to clock function in Arabidopsis thaliana： PSEUDO-RESPONSE REGULATORs, GIGANTEA, and the evening complex genes EARL Y FLOWERING 3, EARLY FLOWERING 4, and LUX ARRHYTHMO. Homol- ogous genes from each group underlie quantitative trait loci that have beneficial influences on key agricul- tural traits, especially flowering time but also yield, biomass, and biennial growth habit. Emerging insights into circadian clock regulation of other fundamental plant processes, including responses to abiotic and biotic stresses, are discussed to highlight promising avenues for further crop improvement.
