Microtubules are dynamic cytoskeleton structures playing fundamental roles in plant responses to salt stress. The precise mechanisms by which micro-tubule organization is regulated under salt stress are largely unknown. Here, we report that Arabidopsis thaliana MICROTUBULE-DESTABILIZING PROTEIN 25 (MDP25; also known as PLASMA MEMBRANE-ASSOCIATED CATION-BINDING PROTEIN 1 (PCaP1)) helps regulate microtubule organization. Under salt treatment, elevated cytosolic Ca2+ con-centration caused MDP25 to partially dissociate from the plasma membrane, promoting microtubule de-polymerization. When Ca2+signaling was blocked by BAPTA-AM or LaCl3, microtubule depolymerization in wild-type and MDP25-overexpressing cells was slower, while there was no obvious change in mdp25 cells. Knockout of MDP25 improved microtubule re-assembly and was conducive to microtubule integrity under long-term salt treatment and microtubule re-covery after salt stress. Moreover, mdp25 seedlings exhibited a higher survival rate under salt stress. The presence microtubule-disrupting reagent oryzalin or microtubule-stabilizing reagent paclitaxel differ-entially affected the survival rates of different geno-types under salt stress. MDP25 promoted micro-tubule instability by affecting the catastrophe and rescue frequencies, shrinkage rate and time in pause phase at the microtubule plus-end and the depoly-merization rate at the microtubule minus-end. These findings reveal a role for MDP25 in regulating microtubule organization under salt treatment by affecting microtubule dynamics.

Peizhi Yang;Jingwei Jin;Jingru Zhang;Dan Wang;Xuechun Bai;Wenfei Xie;Tianming Hu;Xuan Zhao;Tonglin Mao;Tao Qin

College of Grassland Agriculture,Northwest A&F University,Yangling 712100,China;Research Center of Chinese Jujube,Hebei Agricultural University,Baoding 071001,China;College of Horticulture,Hebei Agricultural University,Baoding 071001,China;State Key Laboratory of Plant Physiology and Biochemistry,Department of Plant Sciences,College of Biological Sciences,China Agricultural University,Beijing 100193,China

植物学报（英文版）

[1]Peizhi Yang;Jingwei Jin;Jingru Zhang;Dan Wang;Xuechun Bai;Wenfei Xie;Tianming Hu;Xuan Zhao;Tonglin Mao;Tao Qin-.MDP25 mediates the fine-tuning of microtubule organization in response to salt stressOO)[J].植物学报（英文版）,2022(06):1181-1195

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