Salt stress severely limits rice growth and productivity.Auxin signaling has a well-documented role in development,but its role in rice salt stress responses is far from clear.In this study,we identified OsARF12,an au...Salt stress severely limits rice growth and productivity.Auxin signaling has a well-documented role in development,but its role in rice salt stress responses is far from clear.In this study,we identified OsARF12,an auxin response factor,as a critical positive regulator of salt tolerance in rice.Transcript analysis revealed salt-induced upregulation of OsARF12.More importantly,OsARF12 overexpression(OsARF12-OX)induced significantly increased survival rates and reduced biomass loss under 200 mmol L^(−1)NaCl treatment compared with wild-type(WT)plants,and OsARF12 knockout(OsARF12-KO)using CRISPR-Cas9 showed the opposite tendency.Physiological analyses revealed that OsARF12-OX plants mitigated salt-induced oxidative damage by enhancing ROS scavenging capacity and promoting Na^(+)/K^(+)homeostasis as well as through their superior photosynthetic efficiency under 200 mmol L^(−1)NaCl treatment,which was consistent with the upregulation of differentially expressed genes involved in ROS scavenging,photosynthesis and ion transport pathways.Furthermore,auxin receptor genes or transcription inhibitor genes were upregulated or downregulated in OsARF12-OX lines compared with WT plants under salt stress,respectively.Biochemical assays indicated that OsARF12 acts as a transcriptional activator,directly binding to TGTC-box motifs in the promoters of the key ion transporters OsSOS1 and OsHKT1;5 to reduce shoot Na^(+)content and the Na^(^(+))/K^(+)ratio,thereby increasing salt tolerance.These findings revealed the potential role of OsARF12 in increasing salt tolerance by integrating auxin signaling with ROS scavenging,ionic homeostasis and photosynthetic networks,offering valuable targets for breeding resilient rice varieties.展开更多
Grain weight and quality are always determined by grain filling.Plant microRNAs have drawn attention as key targets for regulation of grain size and yield.However,the mechanisms that underlie grain size regulation rem...Grain weight and quality are always determined by grain filling.Plant microRNAs have drawn attention as key targets for regulation of grain size and yield.However,the mechanisms that underlie grain size regulation remain largely unclear because of the complex networks that control this trait.Our earlier studies demonstrated that suppressed expression of miR167(STTM/MIM167)substantially increased grain weight.In a field test,the yield increased up to 12.90%-21.94% because of a significantly enhanced grain filling rate.Here,biochemical and genetic analyses revealed the regulatory effects of miR159 on miR167 expression.Further analysis indicated that OsARF12 is the major mediator by which miR167 regulates rice grain filling.Overexpression of OsARF12 produced grain weight and grain filling phenotypes resembling those of STTM/MIM167 plants.Upon in-depth analysis,we found that OsARF12 activates OsCDKF;2 expression by directly binding to the TGTCGG motif in its promoter region.Flow cytometry analysis of young panicles from OsARF12-overexpressing plants and examination of cell number in cdkf;2 mutants verified that OsARF12 positively regulates grain filling and grain size by targeting OsCDKF;2.Moreover,RNA sequencing results suggested that the miR167-OsARF12 module is involved in the cell development process and hormone pathways.OsARF12-overexpressing plants and cdkf;2 mutants exhibited enhanced and reduced sensitivity to exogenous auxin and brassinosteroid(BR)treatment,confirming that targeting of OsCDKF;2 by OsARF12 mediates auxin and BR signaling.Our results reveal that the miR167-OsARF12 module works downstream of miR159 to regulate rice grain filling and grain size via OsCDKF;2 by controlling cell division and mediating auxin and BR signals.展开更多
基金funded by National Natural Science Foundation of China(NSFC 32272014)Program for Innovative Research Team(in Science and Technology)in University of Henan Province(25IRTSTHN030)+2 种基金Henan Provincial Science and Technology Research Project(252102111144)the Key Laboratory of Functional Agriculture of Guizhou Province([2023]007)the Key Laboratory of Molecular Breeding for Grain and Oil Crops of Guizhou Province([2023]008).
文摘Salt stress severely limits rice growth and productivity.Auxin signaling has a well-documented role in development,but its role in rice salt stress responses is far from clear.In this study,we identified OsARF12,an auxin response factor,as a critical positive regulator of salt tolerance in rice.Transcript analysis revealed salt-induced upregulation of OsARF12.More importantly,OsARF12 overexpression(OsARF12-OX)induced significantly increased survival rates and reduced biomass loss under 200 mmol L^(−1)NaCl treatment compared with wild-type(WT)plants,and OsARF12 knockout(OsARF12-KO)using CRISPR-Cas9 showed the opposite tendency.Physiological analyses revealed that OsARF12-OX plants mitigated salt-induced oxidative damage by enhancing ROS scavenging capacity and promoting Na^(+)/K^(+)homeostasis as well as through their superior photosynthetic efficiency under 200 mmol L^(−1)NaCl treatment,which was consistent with the upregulation of differentially expressed genes involved in ROS scavenging,photosynthesis and ion transport pathways.Furthermore,auxin receptor genes or transcription inhibitor genes were upregulated or downregulated in OsARF12-OX lines compared with WT plants under salt stress,respectively.Biochemical assays indicated that OsARF12 acts as a transcriptional activator,directly binding to TGTC-box motifs in the promoters of the key ion transporters OsSOS1 and OsHKT1;5 to reduce shoot Na^(+)content and the Na^(^(+))/K^(+)ratio,thereby increasing salt tolerance.These findings revealed the potential role of OsARF12 in increasing salt tolerance by integrating auxin signaling with ROS scavenging,ionic homeostasis and photosynthetic networks,offering valuable targets for breeding resilient rice varieties.
基金funded by the National Natural Science Foundation of China(NSFC,32272014,32001440,31971846,and 31871554)the Natural Science Foundation of Henan Province-Excellent Youth Fund(222300420049)+2 种基金the Central Plains Talents Program of Henan Province(Talent Training Series)-Top Young Talents in Central Plains(ZYY-CYU202012170)the Support Plan for Scientific and Technological Innovation Talents in Colleges and Universities of Henan Province(21HAS-TIT037)the China Postdoctoral Science Foundation(2020M682294).
文摘Grain weight and quality are always determined by grain filling.Plant microRNAs have drawn attention as key targets for regulation of grain size and yield.However,the mechanisms that underlie grain size regulation remain largely unclear because of the complex networks that control this trait.Our earlier studies demonstrated that suppressed expression of miR167(STTM/MIM167)substantially increased grain weight.In a field test,the yield increased up to 12.90%-21.94% because of a significantly enhanced grain filling rate.Here,biochemical and genetic analyses revealed the regulatory effects of miR159 on miR167 expression.Further analysis indicated that OsARF12 is the major mediator by which miR167 regulates rice grain filling.Overexpression of OsARF12 produced grain weight and grain filling phenotypes resembling those of STTM/MIM167 plants.Upon in-depth analysis,we found that OsARF12 activates OsCDKF;2 expression by directly binding to the TGTCGG motif in its promoter region.Flow cytometry analysis of young panicles from OsARF12-overexpressing plants and examination of cell number in cdkf;2 mutants verified that OsARF12 positively regulates grain filling and grain size by targeting OsCDKF;2.Moreover,RNA sequencing results suggested that the miR167-OsARF12 module is involved in the cell development process and hormone pathways.OsARF12-overexpressing plants and cdkf;2 mutants exhibited enhanced and reduced sensitivity to exogenous auxin and brassinosteroid(BR)treatment,confirming that targeting of OsCDKF;2 by OsARF12 mediates auxin and BR signaling.Our results reveal that the miR167-OsARF12 module works downstream of miR159 to regulate rice grain filling and grain size via OsCDKF;2 by controlling cell division and mediating auxin and BR signals.
