ABNORMAL SHOOT 6 interacts with KATANIN 1 and SHADE AVOIDANCE 4 to promote cortical microtubule severing and ordering in Arabidopsis

作     者：Yuanfeng Li Meng Deng Haofeng Liu Yan Li Yu Chen Min Jia Hui Xue Jingxia Shao Jun Zhao Yafei Qi Lijun An Fei Yu Xiayan Liu Yuanfeng Li;Meng Deng;Haofeng Liu;Yan Li;Yu Chen;Min Jia;Hui Xue;Jingxia Shao;Jun Zhao;Yafei Qi;Lijun An;Fei Yu;Xiayan Liu

作者机构：State Key Laboratory of Crop Stress Biology for Arid Areas and College of Life SciencesNorthwest A&F UniversityYangling 712100China Present Address:Department of Plant&Microbial BiologyUniversity of California BerkeleyCalifornia 94720USA 

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

年 卷 期：2021年第63卷第4期

页      面：646-661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：the Teaching and Research Core Facility at the College of Life Sciences,NWAFU for support in this work supported by grants from the National Natural Science Foundation of China(31770205 and 31970186 to X.L.,31870268 to F.Y.)。 

主　　题：ABS red ABNORMAL SHOOT 6 interacts with KATANIN 1 and SHADE AVOIDANCE 4 to promote cortical microtubule severing and ordering in Arabidopsis 

摘      要：Plant interphase cortical microtubules(cMTs)mediate anisotropic cell expansion in response to environmental and developmental cues.In Arabidopsis thaliana,KATANIN 1(KTN1),the p60 catalytic subunit of the conserved MT-severing enzyme katanin,is essential for cMT ordering and anisotropic cell expansion.However,the regulation of KTN1-mediated cMT severing and ordering remains unclear.In this work,we report that the Arabidopsis IQ67 DOMAIN(IQD)family gene ABNORMAL SHOOT 6(ABS6)encodes a MT-associated protein.Overexpression of ABS6 leads to elongated cotyledons,directional pavement cell expansion,and highly ordered transverse cMT arrays.Genetic suppressor analysis revealed that ABS6-mediated cMT ordering is dependent on KTN1 and SHADE AVOIDANCE 4(SAV4).Live imaging of cMT dynamics showed that both ABS6 and SAV4 function as positive regulators of cMT severing.Furthermore,ABS6 directly interacts with KTN1 and SAV4 and promotes their recruitment to the cMTs.Finally,analysis of loss-of-function mutant combinations showed that ABS6,SAV4,and KTN1 work together to ensure the robust ethylene response in the apical hook of dark-grown seedlings.Together,our findings establish ABS6 and SAV4 as positive regulators of cMT severing and ordering,and highlight the role of cMT dynamics in fine-tuning differential growth in plants.