SIZ1 negatively regulates aluminum resistance by mediating the STOP1–ALMT1 pathway in Arabidopsis

作     者：Jiameng Xu Jiayong Zhu Jiajia Liu Junxia Wang Zhaojun Ding Huiyu Tian Jiameng Xu;Jiayong Zhu;Jiajia Liu;Junxia Wang;Zhaojun Ding;Huiyu Tian

作者机构：The Key Laboratory of Plant Development and Environmental Adaptation BiologyMinistry of EducationCollege of Life SciencesShandong UniversityQingdao 266237China 

出 版 物：《Journal of Integrative Plant Biology》 (植物学报（英文版）)

年 卷 期：2021年第63卷第6期

页      面：1147-1160页

核心收录：

学科分类：0710[理学-生物学] 09[农学] 0903[农学-农业资源与环境] 0901[农学-作物学] 0703[理学-化学] 0902[农学-园艺学] 

基　　金：supported by the National Natural Science Foundation of China(31470371 and 31770305) by Qingdao's Leading Technology Innovator Project by Youth Interdisciplinary Science and Innovative Research Groups of Shandong University(2020QNQT014)。 

主　　题：ALMT1 aluminum SIZ1 STOP1 SUMOylation 

摘      要：Sensitive to proton rhizotoxicity 1(STOP1) functions as a crucial regulator of root growth during aluminum(Al) stress. However, how this transcription factor is regulated by Al stress to affect downstream genes expression is not well understood. To explore the underlying mechanisms of the function and regulation of STOP1, we employed a yeast two hybrid screen to identify STOP1-interacting proteins. The SUMO E3 ligase SIZ1, was found to interact with STOP1 and mainly facilitate its SUMO modification at K40 and K212 residues. Simultaneous introduction of K40 R and K212 R substitutions in STOP1 enhances its transactivation activity to upregulate the expression of aluminum-activated malate transporter 1(ALMT1)via increasing the association with mediator 16(MED16) transcriptional co-activator. Loss of function of SIZ1 causes highly increased expression of ALMT1, thus enhancing Al-induced malate exudation and Al tolerance. Also, we found that the protein level of SIZ1 is reduced in response to Al stress. Genetic evidence demonstrates that STOP1/ALMT1 is epistatic to SIZ1 in regulating root growth response to Al stress. This study suggests a mechanism about how the SIZ1–STOP1–ALMT1 signaling module is involved in root growth response to Al stress.