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
Symbiotic root nodules are root lateral organs of plants in which nitrogen-fixing bacteria(rhizobia)convert atmospheric nitrogen to ammonia.The formation and number of nodules in legumes are precisely controlled by a ...Symbiotic root nodules are root lateral organs of plants in which nitrogen-fixing bacteria(rhizobia)convert atmospheric nitrogen to ammonia.The formation and number of nodules in legumes are precisely controlled by a rhizobia-induced signal cascade and host-controlled autoregulation of nodulation(AON).However,how these pathways are integrated and their underlying mechanisms are unclear.Here,we report that microRNA172c(miR172c)activates soybean(Glycine max)R hizobia-induced CLE1(GmRICI)and GmRIC2 by removing the transcriptional repression of these genes by Nodule Number Control 1(NNC1),leading to the activation of the AON pathway.NNC1 interacts with GmNINa,the soybean ortholog of Lotus NODULE INCEPTION(NIN),and hampers its transcriptional activation o i G m RICI and GmRIC2.Importantly,GmNINa acts as a transcriptional activator of miR172c.Intriguingly,NNC1 can transcriptionally repress miR172c expression,adding a negative feedback loop into the NNC1 regulatory network.Moreover,GmNINa interacts with NNC1 and can relieve the NNC1-mediated repression of miR172c transcription.Thus,the GmNINa-miR172c-NNC1 network is a master switch that coordinately regulates and optimizes NF and AON signaling,supporting the balance between nodulation and AON in soybean.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).
基金the National Key Research and Development Program of China(2016YFA0500503)the National Natural Science Foundation of China(31730066 and 31230050)+1 种基金the Ministry of Agriculture of the People's Public of China(2018ZX0800919B and 2014ZX0800929B)Huazhong Agricultural University Scientific&Technological Selfinnovation Foundation(2015RC014).
文摘Symbiotic root nodules are root lateral organs of plants in which nitrogen-fixing bacteria(rhizobia)convert atmospheric nitrogen to ammonia.The formation and number of nodules in legumes are precisely controlled by a rhizobia-induced signal cascade and host-controlled autoregulation of nodulation(AON).However,how these pathways are integrated and their underlying mechanisms are unclear.Here,we report that microRNA172c(miR172c)activates soybean(Glycine max)R hizobia-induced CLE1(GmRICI)and GmRIC2 by removing the transcriptional repression of these genes by Nodule Number Control 1(NNC1),leading to the activation of the AON pathway.NNC1 interacts with GmNINa,the soybean ortholog of Lotus NODULE INCEPTION(NIN),and hampers its transcriptional activation o i G m RICI and GmRIC2.Importantly,GmNINa acts as a transcriptional activator of miR172c.Intriguingly,NNC1 can transcriptionally repress miR172c expression,adding a negative feedback loop into the NNC1 regulatory network.Moreover,GmNINa interacts with NNC1 and can relieve the NNC1-mediated repression of miR172c transcription.Thus,the GmNINa-miR172c-NNC1 network is a master switch that coordinately regulates and optimizes NF and AON signaling,supporting the balance between nodulation and AON in soybean.
