The plant hormone auxin plays a critical role in regulating plant growth and development. Recent advances have been made in the understanding of auxin response pathways, primarily by the characterization of auxin resp...The plant hormone auxin plays a critical role in regulating plant growth and development. Recent advances have been made in the understanding of auxin response pathways, primarily by the characterization of auxin response mutants in Arabidopsis. In addition, microRNAs （miRNAs） have been shown to be critical regulators of genes important for normal plant development and physiology. However, little is known about possible interactions between miRNAs and hormonal signaling during normal development. Here we show that an Arabidopsis microRNA, miR167, which has a complementary sequence to a portion of the A UXINRESPONSE FACTOR6 （ARF6） and ARF8 mRNAs, can cause transcript degradation for ARF8, but not for ARF6. We report phenotypic characterizations of 35S：：MIR167b transgenic lines, and show that severe 35S：：MIR167b transgenic lines had phenotypes similar to those of an arf6 arf8 double mutant. The transgenic phenotypes suggest that miR167 may repress ARF6 at the level of translation. We demonstrate that the transgenic plants are defective in all four whods of floral organs. In the transgenic flowers, filaments were abnormally short, anthers could not properly release pollen, and pollen grains did not germinate. Our results provide an important link between the miRNA-mediated regulatory pathway of gene expression and the auxin signaling network promoting plant reproductive development.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
Grain size is one of the most important factors that control rice yield,as it is associated with grain weight(GW).To date,dozens of rice genes that regulate grain size have been isolated;however,the regulatory mechani...Grain size is one of the most important factors that control rice yield,as it is associated with grain weight(GW).To date,dozens of rice genes that regulate grain size have been isolated;however,the regulatory mechanism underlying GW control is not fully understood.Here,the quantitative trait locus qGL5 for grain length(GL)and GW was identified in recombinant inbred lines of 9311 and Nipponbare(NPB)and fine mapped to a candidate gene,OsAUX3.Sequence variations between 9311 and NPB in the OsAUX3 promoter and loss of function of OsAUX3 led to higher GL and GW.RNA sequencing,gene expression quantification,dual-luciferase reporter assays,chromatin immunoprecipitation-quantitative PCR,and yeast one-hybrid assays demonstrated that OsARF6 is an upstream transcription factor regulating the expression of OsAUX3.OsARF6 binds directly to the auxin response elements of the OsAUX3 promoter,covering a single-nucleotide polymorphism site between 9311 and NPB/Dongjin/Hwayoung,and thereby controls GL by altering longitudinal expansion and auxin distribution/content in glume cells.Furthermore,we showed that miR167a positively regulate GL and GW by directing OsARF6 mRNA silencing.Taken together,our study reveals that a novel miR167a-OsARF6-OsAUX3 module regulates GL and GW in rice,providing a potential target for the improvement of rice yield.展开更多
文摘The plant hormone auxin plays a critical role in regulating plant growth and development. Recent advances have been made in the understanding of auxin response pathways, primarily by the characterization of auxin response mutants in Arabidopsis. In addition, microRNAs （miRNAs） have been shown to be critical regulators of genes important for normal plant development and physiology. However, little is known about possible interactions between miRNAs and hormonal signaling during normal development. Here we show that an Arabidopsis microRNA, miR167, which has a complementary sequence to a portion of the A UXINRESPONSE FACTOR6 （ARF6） and ARF8 mRNAs, can cause transcript degradation for ARF8, but not for ARF6. We report phenotypic characterizations of 35S：：MIR167b transgenic lines, and show that severe 35S：：MIR167b transgenic lines had phenotypes similar to those of an arf6 arf8 double mutant. The transgenic phenotypes suggest that miR167 may repress ARF6 at the level of translation. We demonstrate that the transgenic plants are defective in all four whods of floral organs. In the transgenic flowers, filaments were abnormally short, anthers could not properly release pollen, and pollen grains did not germinate. Our results provide an important link between the miRNA-mediated regulatory pathway of gene expression and the auxin signaling network promoting plant reproductive development.
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.
基金This project was funded by grants from the National Key Research and Development Program of China(2016YFD0100400)the National Natural Science Foundation of China(32060451)the Zhejiang Provincial Nat-ural Science Foundation of China(grant no.L Z19C020001).
文摘Grain size is one of the most important factors that control rice yield,as it is associated with grain weight(GW).To date,dozens of rice genes that regulate grain size have been isolated;however,the regulatory mechanism underlying GW control is not fully understood.Here,the quantitative trait locus qGL5 for grain length(GL)and GW was identified in recombinant inbred lines of 9311 and Nipponbare(NPB)and fine mapped to a candidate gene,OsAUX3.Sequence variations between 9311 and NPB in the OsAUX3 promoter and loss of function of OsAUX3 led to higher GL and GW.RNA sequencing,gene expression quantification,dual-luciferase reporter assays,chromatin immunoprecipitation-quantitative PCR,and yeast one-hybrid assays demonstrated that OsARF6 is an upstream transcription factor regulating the expression of OsAUX3.OsARF6 binds directly to the auxin response elements of the OsAUX3 promoter,covering a single-nucleotide polymorphism site between 9311 and NPB/Dongjin/Hwayoung,and thereby controls GL by altering longitudinal expansion and auxin distribution/content in glume cells.Furthermore,we showed that miR167a positively regulate GL and GW by directing OsARF6 mRNA silencing.Taken together,our study reveals that a novel miR167a-OsARF6-OsAUX3 module regulates GL and GW in rice,providing a potential target for the improvement of rice yield.
