Lin Xiaoli, Xiao Yu, Song Yongping, Gan Cong, Deng Xingguang, Wang Peng, Liu Jialong, Jiang Zhishu, Peng Limei, Zhou Dahu, He Xiaopeng, Bian Jianmin, Zhu Changlan, Liu Bo, He Haohua, Xu Jie
Key Laboratory of Crop Physiology, Ecology, and Genetic Breeding of the Ministry of Education, Jiangxi Agricultural University, Nanchang, Jiangxi, China.
Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, State Key Laboratory of Hydraulics and Mountain River Engineering, Sichuan University, Chengdu, Sichuan, China.
Front Plant Sci. 2022 Oct 26;13:1030247. doi: 10.3389/fpls.2022.1030247. eCollection 2022.
In plants, MAP65 preferentially cross-links the anti-parallel microtubules (MTs) and plays an important role for cytokinesis. However, the functions of MAP65 isoforms in rice ( L) are largely unknown. Here, we identified two MAP65-3 homologs in rice, OsMAP65-3.1 and OsMAP65-3.2. We found that both OsMAP65-3.1 and OsMAP65-3.2 were similar in dimerization and location to AtMAP65-3, and the expression of either rice genes driven by the promoter suppressed the cytokinesis failure and growth defect of . However, with native promoter also recovered the , but with its own promoter had no effects. but not was actively expressed in tissues enriched with dividing cells. R1R2R3-Myb (MYB3R) transcription factors directly bound to the promoter but not that of . Furthermore, had no obvious phenotype, while either or was lethal. The eminent MTs around the daughter nuclei and cytokinesis defects were frequently observed in -defective plants. Taken together, our findings suggest that , rather than , plays essential roles in rice cytokinesis resulting from their differential expression which were passably directly regulated by OsMYB3Rs.
在植物中，微管相关蛋白65（MAP65）优先交联反平行微管（MTs），并在胞质分裂中发挥重要作用。然而，MAP65亚型在水稻（Oryza sativa L.）中的功能 largely unknown。在这里，我们在水稻中鉴定出两个MAP65 - 3同源物，即OsMAP65 - 3.1和OsMAP65 - 3.2。我们发现，OsMAP65 - 3.1和OsMAP65 - 3.2在二聚化和定位方面与拟南芥微管相关蛋白65 - 3（AtMAP65 - 3）相似，并且由35S启动子驱动的任何一个水稻基因的表达都能抑制拟南芥的胞质分裂失败和生长缺陷。然而，由其天然启动子驱动的OsMAP65 - 3.1也能恢复拟南芥的表型，但由其自身启动子驱动的OsMAP65 - 3.2则没有效果。OsMAP65 - 3.2而非OsMAP65 - 3.1在富含分裂细胞的组织中活跃表达。R1R2R3 - Myb（MYB3R）转录因子直接结合到OsMAP65 - 3.2的启动子上，而不结合OsMAP65 - 3.1的启动子。此外，OsMAP65 - 3.1没有明显的表型，而OsMAP65 - 3.2缺失或过表达则是致死的。在OsMAP65 - 3.2缺陷型植物中经常观察到子核周围明显的微管和胞质分裂缺陷。综上所述，我们的研究结果表明，OsMAP65 - 3.2而非OsMAP65 - 3.1在水稻胞质分裂中起关键作用，这是由于它们的差异表达，而这种差异表达可能直接受OsMYB3Rs的调控。
