A rice tubulin tyrosine ligase‐like 12 protein affects the dynamic and orientation of microtubules

• Published in: Journal of integrative plant biology 2021-05, Vol.63 (5), p.848-864
• Main Authors: Zhang, Kunxi, Zhu, Xin, Durst, Steffen, Hohenberger, Petra, Han, Min‐Jung, An, Gynheung, Sahi, Vaidurya P., Riemann, Michael, Nick, Peter
• Format: Article
• Language: English
• Subjects: Carboxypeptidase; Carboxypeptidases - genetics; Carboxypeptidases - metabolism; Cell walls; Coleoptile; Eukaryotes; Homology; microtubule; Microtubules; Microtubules - metabolism; Nicotiana - metabolism; Oryza - genetics; Oryza - metabolism; Peptide Synthases - genetics; Peptide Synthases - metabolism; Phenotypes; phragmoplast; Plant growth; Proteins; Relative abundance; Rice; Tobacco; tobacco BY‐2; Tubulin; Tubulin - genetics; Tubulin - metabolism; tubulin detyrosination; tubulin tyrosine carboxypeptidase; tubulin tyrosine ligase; tubulin tyrosine ligase‐like 12; Tyrosine
• ISSN: 1672-9072; 1744-7909
• DOI: 10.1111/jipb.13059

The detyrosination/retyrosination cycle is the most common post‐translational modification of α‐tubulin. Removal of the conserved C‐terminal tyrosine of α‐tubulin by a still elusive tubulin tyrosine carboxypeptidase, and religation of this tyrosine by a tubulin tyrosine ligase (TTL), are probably common to all eukaryotes. Interestingly, for plants, the only candidates qualifying as potential TTL homologs are the tubulin tyrosine ligase‐like 12 proteins. To get insight into the biological functions of these potential TTL homologs, we cloned the rice TTL‐like 12 protein (OsTTLL12) and generated overexpression OsTTLL12‐RFP lines in both rice and tobacco BY‐2 cells. We found, unexpectedly, that overexpression of this OsTTLL12‐RFP increased the relative abundance of detyrosinated α‐tubulin in both coleoptile and seminal root, correlated with more stable microtubules. This was independent of the respective orientation of cortical microtubule, and followed by correspondingly changing growth of coleoptiles and seminal roots. A perturbed organization of phragmoplast microtubules and disoriented cell walls were further characteristics of this phenotype. Thus, the elevated tubulin detyrosination in consequence of OsTTLL12 overexpression affects structural and dynamic features of microtubules, followed by changes in the axiality of cell plate deposition and, consequently, plant growth. The rice tubulin tyrosine ligase TTLL12 functions in the detyrosination/tyrosination cycle, a common posttranslational modification of α‐tubulin that is important for microtubule stability. OsTTLL12 overexpression affected microtubule dynamics and organization, thus altering plant growth and development.