In response to competition for light from their neighbors,shade-intolerant plants flower precociously to ensure reproductive success and survival.However,the molecular mechanisms underlying this key developmental swit...In response to competition for light from their neighbors,shade-intolerant plants flower precociously to ensure reproductive success and survival.However,the molecular mechanisms underlying this key developmental switch are not well understood.Here,we show that a pair of Arabidopsis transcription factors essential for phytochrome A signaling,FAR-RED ELONGATED HYPOCOTYL3(FHY3)and FAR-RED IMPAIRED RESPONSE1(FAR1),regulate flowering time by integrating environmental light signals with the miR156-SPL module-mediated aging pathway.We found that FHY3 and FAR1 directly interact with three flowering-promoting SQUAMOSA-PROMOTER BINDING PROTEIN-LIKE(SPL)transcription factors,SPL3,SPL4,and SPL5,and inhibit their binding to the promoters of several key flowering regulatory genes,including FRUITFUL(FUL),LEAFY(LFY),APETALA1(AP1),and MIR172C,thus downregulating their transcript levels and delaying flowering.Under simulated shade conditions,levels of SPL3/4/5 proteins increase,whereas levels of FHY3 and FAR1 proteins decline,thus releasing SPL3/4/5 from FHY3/FAR1 inhibition to allow activation of FUL,LFY,AP1,and MIR172C and,consequently,early flowering.Taken together,these results unravel a novel mechanism whereby plants regulate flowering time by integrating environmental cues(such as light conditions)and an internal developmental program(the miR156-SPL module-mediated aging pathway).展开更多
基金supported by grants from National Natural Science Foundation of China(31770210 and 31570191)National Key Research and D evelopm ent Program of China(2016YFD0100303).
文摘In response to competition for light from their neighbors,shade-intolerant plants flower precociously to ensure reproductive success and survival.However,the molecular mechanisms underlying this key developmental switch are not well understood.Here,we show that a pair of Arabidopsis transcription factors essential for phytochrome A signaling,FAR-RED ELONGATED HYPOCOTYL3(FHY3)and FAR-RED IMPAIRED RESPONSE1(FAR1),regulate flowering time by integrating environmental light signals with the miR156-SPL module-mediated aging pathway.We found that FHY3 and FAR1 directly interact with three flowering-promoting SQUAMOSA-PROMOTER BINDING PROTEIN-LIKE(SPL)transcription factors,SPL3,SPL4,and SPL5,and inhibit their binding to the promoters of several key flowering regulatory genes,including FRUITFUL(FUL),LEAFY(LFY),APETALA1(AP1),and MIR172C,thus downregulating their transcript levels and delaying flowering.Under simulated shade conditions,levels of SPL3/4/5 proteins increase,whereas levels of FHY3 and FAR1 proteins decline,thus releasing SPL3/4/5 from FHY3/FAR1 inhibition to allow activation of FUL,LFY,AP1,and MIR172C and,consequently,early flowering.Taken together,these results unravel a novel mechanism whereby plants regulate flowering time by integrating environmental cues(such as light conditions)and an internal developmental program(the miR156-SPL module-mediated aging pathway).
