PCH1 and PCHL Directly Interact with PIF1,Promote Its Degradation,and Inhibit Its Transcriptional Function during Photomorphogenesis  

作　　者：Mei-Chun Cheng Beatrix Enderle Praveen Kumar Kathare Rafya Islam Andreas Hiltbrunner Enamul Huq 

机构地区：[1]Molecular Biosciences,University of Texas at Austin,NHB 2.616,Stop A5000,100 East 24th Street,Austin,TX 78712-1095,USA [2]Institute of Biology II,Faculty of Biology,University of Freiburg,Freiburg,Germany [3]Signalling Research Centres BIOSS and CIBSS,University of Freiburg,Freiburg,Germany

出　　处：《Molecular Plant》2020年第3期499-514,共16页分子植物（英文版）

基　　金：supported by grants from the National Institutes of Health(GM-114297);National Science Foundation(MCB-1543813)to E.H.and by a grant from the German Research Foundation(DFG)to A.H.(HI 1369/7-1);by the DFG under Germany’s Excellence Strategy(CIBSS-EXC-2189-Project ID 390939984).

摘　　要：PHOTOPERIODIC CONTROL OF HYPOCOTYL 1(PCH1)and PCH1-LIKE(PCHL)were shown to directly bind to phytochrome B(phyB)and suppress phyB thermal reversion,resulting in plants with dramatically enhanced light sensitivity.Here,we show that PCH1 and PCHL also positively regulate various light responses,including seed germination,hypocotyl gravitropism,and chlorophyll biosynthesis,by physically interacting with PHYTOCHROME INTERACTING FACTOR 1(PIF1)and CONSTITUTIVE PHOTOMORPHO-GENIC 1(COP1).PCH1 and PCHL interact with PIF1 both in the dark and light,and regulate PIF1 abundance.Moreover,PCH1 and PCHL facilitate the physical interaction between phyB and PIF1 in vivo to promote the light-induced degradation of PIF1.PCH1 and PCHL also inhibit the DNA-binding ability of PIF1 to negatively regulate the expressions of PIF1 target genes.In addition,PCH1 and PCHL interact with COP1 and undergo degradation through the 26S proteasome pathway in the dark.Consistently,pch1 suppresses cop1 phenotype in darkness.Collectively,our study reveals a novel mechanism by which PCH1 and PCHL regulate diverse light responses not only by stabilizing phyB Pfrform but also by directly interacting with PIF1 and COP1,providing a molecular understanding of the control of hypocotyl growth by these proteins.

关 键 词：Arabidopsis PHYTOCHROME phytochrome interacting factor(PIF) photoperiodic growth protein degradation 

分 类 号：Q94[生物学—植物学]