Plasma membrane vesicles were prepared from the developing cotyledons of common beau (Phaseolus vulgaris L cv Diyundou) by aqueous two-phase partitioning and characterized as to their purity by assaying marker enzymes...Plasma membrane vesicles were prepared from the developing cotyledons of common beau (Phaseolus vulgaris L cv Diyundou) by aqueous two-phase partitioning and characterized as to their purity by assaying marker enzymes for other membranes.The putative plasma membrane fraction was minimally contaminated by membranes Other than plasma membrane and hence was of high purity. It exhibited a Ca2+dependent ATPase activity, which was inhibited by 1μ mol/L EB and promoted by calcium ionophore A23187. Such an activity was responsible for the observed ATPdependent 45Ca2+ uptake into inside-out plasma membrane vesicles. This process was stimulated by 0.6μmol/L CaM and 20μmol/L IAA but inhibited by 2μmol/L ABA and abolished by A23187. Possible role of cytoplasmic Ca2+ in mediating phytohormones activity is discussed.展开更多
Although green light(GL)is located in the middle of the visible light spectrum and regulates a series of plant developmental processes,the mechanism by which it regulates seedling development is largely unknown.In thi...Although green light(GL)is located in the middle of the visible light spectrum and regulates a series of plant developmental processes,the mechanism by which it regulates seedling development is largely unknown.In this study,we demonstrated that GL promotes atypical photomorphogenesis in Arabidopsis thaliana via the dual regulations of phytochrome B(phyB)and phyA.Although the Pr-to-Pfr conversion rates of phyB and phyA under GL were lower than those under red light(RL)in a fluence rate-dependent and time-dependent manner,long-term treatment with GL induced high Pfr/Pr ratios of phyB and phyA.Moreover,GL induced the formation of numerous small phyB photobodies in the nucleus,resulting in atypical photomorphogenesis,with smaller cotyledon opening angles and longer hypocotyls in seedlings compared to RL.The abundance of phyA significantly decreased after short-and long-term GL treatments.We determined that four major PHYTOCHROME-INTERACTING FACTORs(PIFs:PIF1,PIF3,PIF4,and PIF5)act downstream of phyB in GL-mediated cotyledon opening.In addition,GL plays opposite roles in regulating different PIFs.For example,under continuous GL,the protein levels of all PIFs decreased,whereas the transcript levels of PIF4 and PIF5 strongly increased compared with dark treatment.Taken together,our work provides a detailed molecular framework for understanding the role of the antagonistic regulations of phyB and phyA in GL-mediated atypical photomorphogenesis.展开更多
文摘Plasma membrane vesicles were prepared from the developing cotyledons of common beau (Phaseolus vulgaris L cv Diyundou) by aqueous two-phase partitioning and characterized as to their purity by assaying marker enzymes for other membranes.The putative plasma membrane fraction was minimally contaminated by membranes Other than plasma membrane and hence was of high purity. It exhibited a Ca2+dependent ATPase activity, which was inhibited by 1μ mol/L EB and promoted by calcium ionophore A23187. Such an activity was responsible for the observed ATPdependent 45Ca2+ uptake into inside-out plasma membrane vesicles. This process was stimulated by 0.6μmol/L CaM and 20μmol/L IAA but inhibited by 2μmol/L ABA and abolished by A23187. Possible role of cytoplasmic Ca2+ in mediating phytohormones activity is discussed.
基金supported by the Excellent Young Talents Fund Program of Higher Education Institutions of Anhui Province(2023AH030049)Anhui Agricultural University Startup Fund(grant no.rc422115,to J.J.L.)Anhui Province Fund for University Development(22103103)。
文摘Although green light(GL)is located in the middle of the visible light spectrum and regulates a series of plant developmental processes,the mechanism by which it regulates seedling development is largely unknown.In this study,we demonstrated that GL promotes atypical photomorphogenesis in Arabidopsis thaliana via the dual regulations of phytochrome B(phyB)and phyA.Although the Pr-to-Pfr conversion rates of phyB and phyA under GL were lower than those under red light(RL)in a fluence rate-dependent and time-dependent manner,long-term treatment with GL induced high Pfr/Pr ratios of phyB and phyA.Moreover,GL induced the formation of numerous small phyB photobodies in the nucleus,resulting in atypical photomorphogenesis,with smaller cotyledon opening angles and longer hypocotyls in seedlings compared to RL.The abundance of phyA significantly decreased after short-and long-term GL treatments.We determined that four major PHYTOCHROME-INTERACTING FACTORs(PIFs:PIF1,PIF3,PIF4,and PIF5)act downstream of phyB in GL-mediated cotyledon opening.In addition,GL plays opposite roles in regulating different PIFs.For example,under continuous GL,the protein levels of all PIFs decreased,whereas the transcript levels of PIF4 and PIF5 strongly increased compared with dark treatment.Taken together,our work provides a detailed molecular framework for understanding the role of the antagonistic regulations of phyB and phyA in GL-mediated atypical photomorphogenesis.
