SMXL5 attenuates strigolactone signaling in Arabidopsis thaliana by inhibiting SMXL7 degradation  

作　　者：Qingtian Li Haiyang Yu Wenwen Chang Sunhyun Chang Michael Guzman Lionel Faure Eva-Sophie Wallner Heqin Yan Thomas Greb Lei Wang Ruifeng Yao David C.Nelson 

机构地区：[1]Department of Botany and Plant Sciences,University of California,Riverside,Riverside,CA 2521,USA [2]Yazhouwan National Laboratory,Sanya 572025,China [3]Hainan Seed Industry Laboratory,Sanya 57205,China [4]State Key Laboratory of Chemo/Biosensing and Chemometrics,Hunan Provincial Key Laboratory of Plant Functional Genomics and Developmental Regulation,College of Biology,Hunan University,Changsha 410082,China [5]Key Laboratory of Seed Innovation,Center for Agricultural Resources Research,Institute of Genetics and Developmental Biology,Chinese Academy of Sciences,Shijiazhuang,Hebei 050021,China [6]University of Chinese Academy of Sciences,Beijing 10004,China [7]School of the Sciences,Biology Division,Texas Woman’s University,Denton,TX 76204,USA [8]Centre for Organismal Studies(COS),Heidelberg University,6120 Heidelberg,Germany

出　　处：《Molecular Plant》2024年第4期631-647,共17页分子植物（英文版）

基　　金：provided by the National Science Foundation,Division of Integrative Organismal Systems(grants 1737153,1740560,and 1856741)to D.C.N.;the Hainan Seed Industry Laboratory(grant B23C19701)to Q.L.;the National Key Research and Development Program of China(grant 2021YFA1300400);the National Natural Science Foundation of China(grant 32070321);the Shenzhen Science and Technology Innovation Commission(grant 2021Szvup037)to R.Y.;the National Natural Science Foundation of China(grant 32170320);Hebei Natural Science Foundation(grant C2022503003)to L.W.;the Deutsche Forschungsgemeinschaft(grant GR 2104/9-1)to T.G.

摘　　要：Hormone-activated proteolysis is a recurring theme of plant hormone signaling mechanisms.In strigolactone signaling,the enzyme receptor DWARF14(D14)and an F-box protein,MORE AXILLARY GROWTH2(MAX2),mark SUPPRESSOR OF MAX21-LIKE(SMXL)family proteins SMXL6,SMXL7,and SMXL8 for rapid degradation.Removal of these transcriptional corepressors initiates downstream growth responses.The homologous proteins SMXL3,SMXL4,and SMXL5,however,are resistant to MAX2-mediated degradation.We discovered that the smxl4 smxl5 mutant has enhanced responses to strigolactone.SMXL5 attenuates strigolactone signaling by interfering with AtD14-SMXL7 interactions.SMXL5 interacts with AtD14 and SMXL7,providing two possible ways to inhibit SMXL7 degradation.SMXL5 function is partially dependent on an ethylene-responsive-element binding-factor-associated amphiphilic repression(EAR)motif,which typically mediates interactions with the TOPLESS family of transcriptional corepressors.However,we found that loss of the EAR motif reduces SMXL5-SMXL7 interactions and the attenuation of strigolactone signaling by SMXL5.We hypothesize that integration of SMXL5 into heteromeric SMXL complexes reduces the susceptibility of SMXL6/7/8 proteins to strigolactone-activated degradation and that the EAR motif promotes the formation or stability of these complexes.This mechanism may provide a way to spatially or temporally fine-tune strigolactone signaling through the regulation of SMXL5 expression or translation.

关 键 词：ARABIDOPSIS typically INHIBITING 

分 类 号：Q94[生物学—植物学]