Light and gravity coordinately regulate the directional growth of plants.Arabidopsis Gravitropic in the Light 1(GIL1)inhibits the negative gravitropism of hypocotyls in red and far-red light,but the underlying molecul...Light and gravity coordinately regulate the directional growth of plants.Arabidopsis Gravitropic in the Light 1(GIL1)inhibits the negative gravitropism of hypocotyls in red and far-red light,but the underlying molecular mechanisms remain elusive.Our study found that GIL1 is a plasma membrane-localized protein.In endodermal cells of the upper part of hypocotyls,GIL1 controls the negative gravitropism of hypocotyls.GIL1 directly interacts with PIN3 and inhibits the auxin transport activity of PIN3.Mutation of PIN3 suppresses the abnormal gravitropic response of gil1 mutant.The GIL1 protein is unstable in darkness but it is stabilized by red and far-red light.Together,our data suggest that light-stabilized GIL1 inhibits the negative gravitropism of hypocotyls by suppressing the activity of the auxin transporter PIN3,thereby enhancing the emergence of young seedlings from the soil.展开更多
PIN-FORMED(PIN)-dependent directional auxin transport is crucial for plant development. Although the redistribution of auxin mediated by the polarization of PIN3 plays key roles in modulating hypocotyl cell expansion,...PIN-FORMED(PIN)-dependent directional auxin transport is crucial for plant development. Although the redistribution of auxin mediated by the polarization of PIN3 plays key roles in modulating hypocotyl cell expansion, how PIN3 becomes repolarized to the proper sites within hypocotyl cells is poorly understood. We previously generated the clathrin light chain clc2-1 clc3-1 double mutant in Arabidopsis thaliana and found that it has an elongated hypocotyl phenotype compared to the wild type. Here, we performed genetic, cell biology, and pharmacological analyses combined with live-cell imaging to elucidate the molecular mechanism underlying the role of clathrin light chains in hypocotyl elongation. Our analyses indicated that the defects of the double mutant enhanced auxin maxima in epidermal cells, thus, promoting hypocotyl elongation. PIN3 relocated to the lateral sides of hypocotyl endodermal cells in clc2-1 clc3-1 mutants to redirect auxin toward the epidermal cell layers.Moreover, the loss of function of PIN3 largely suppressed the long hypocotyl phenotype of the clc2-1 clc3-1 double mutant, as did treatment with auxin transport inhibitors. Based on these data, we propose that clathrin modulates PIN3 abundance and polarity to direct auxin flux and inhibit cell elongation in the hypocotyl, providing novel insights into the regulation of hypocotyl elongation.展开更多
The H3K27 methyltransferase CLF inhibits lateral root(LR) formation through depositing the repressive H3K27me3 mark to the chromatin of PIN1, a key polar auxin transporter gene. Here, we show that the H3K27me3 demethy...The H3K27 methyltransferase CLF inhibits lateral root(LR) formation through depositing the repressive H3K27me3 mark to the chromatin of PIN1, a key polar auxin transporter gene. Here, we show that the H3K27me3 demethylase REF6 promotes lateral root primordium initiation and LR emergence. REF6 directly binds to the chromatin of PIN1/3/7. Dysfunction in REF6 results in increased levels of H3K27me3 on PIN1/3/7 and suppressed expression of PIN genes. Genetic analysis of the clf ref6 double mutant revealed an antagonistic action between CLF and REF6, in terms of LR formation.Our findings indicate that H3K27 methylation and demethylation activities are likely coordinated to ensure proper LR organogenesis.展开更多
基金supported by the National Natural Science Foundation of China (32350001, 32370306, 32022005)Tsinghua University Dushi Program+1 种基金the Tsinghua-Peking Center for Life Sciencesfunded by grants from the Swiss National Funds (project 31003A_165877 and 310030_197563)
文摘Light and gravity coordinately regulate the directional growth of plants.Arabidopsis Gravitropic in the Light 1(GIL1)inhibits the negative gravitropism of hypocotyls in red and far-red light,but the underlying molecular mechanisms remain elusive.Our study found that GIL1 is a plasma membrane-localized protein.In endodermal cells of the upper part of hypocotyls,GIL1 controls the negative gravitropism of hypocotyls.GIL1 directly interacts with PIN3 and inhibits the auxin transport activity of PIN3.Mutation of PIN3 suppresses the abnormal gravitropic response of gil1 mutant.The GIL1 protein is unstable in darkness but it is stabilized by red and far-red light.Together,our data suggest that light-stabilized GIL1 inhibits the negative gravitropism of hypocotyls by suppressing the activity of the auxin transporter PIN3,thereby enhancing the emergence of young seedlings from the soil.
基金This work was supported by the National Natural Science Foundation of China(Nos.31801193,31820103008,91754104,and 31670283)the Fundamental Research Funds for the Central Universities(Nos.lzujbky-2018-28 and lzujbky-2020-it13)。
文摘PIN-FORMED(PIN)-dependent directional auxin transport is crucial for plant development. Although the redistribution of auxin mediated by the polarization of PIN3 plays key roles in modulating hypocotyl cell expansion, how PIN3 becomes repolarized to the proper sites within hypocotyl cells is poorly understood. We previously generated the clathrin light chain clc2-1 clc3-1 double mutant in Arabidopsis thaliana and found that it has an elongated hypocotyl phenotype compared to the wild type. Here, we performed genetic, cell biology, and pharmacological analyses combined with live-cell imaging to elucidate the molecular mechanism underlying the role of clathrin light chains in hypocotyl elongation. Our analyses indicated that the defects of the double mutant enhanced auxin maxima in epidermal cells, thus, promoting hypocotyl elongation. PIN3 relocated to the lateral sides of hypocotyl endodermal cells in clc2-1 clc3-1 mutants to redirect auxin toward the epidermal cell layers.Moreover, the loss of function of PIN3 largely suppressed the long hypocotyl phenotype of the clc2-1 clc3-1 double mutant, as did treatment with auxin transport inhibitors. Based on these data, we propose that clathrin modulates PIN3 abundance and polarity to direct auxin flux and inhibit cell elongation in the hypocotyl, providing novel insights into the regulation of hypocotyl elongation.
基金supported by the Science and Technology Commission of Shanghai Municipality(15JC1400800 to G.R.)the National Natural Science Foundation of China(31622009 to G.R.,31700246 to J.G.)
文摘The H3K27 methyltransferase CLF inhibits lateral root(LR) formation through depositing the repressive H3K27me3 mark to the chromatin of PIN1, a key polar auxin transporter gene. Here, we show that the H3K27me3 demethylase REF6 promotes lateral root primordium initiation and LR emergence. REF6 directly binds to the chromatin of PIN1/3/7. Dysfunction in REF6 results in increased levels of H3K27me3 on PIN1/3/7 and suppressed expression of PIN genes. Genetic analysis of the clf ref6 double mutant revealed an antagonistic action between CLF and REF6, in terms of LR formation.Our findings indicate that H3K27 methylation and demethylation activities are likely coordinated to ensure proper LR organogenesis.
