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Original Research ARTICLE Provisionally accepted The full-text will be published soon. Notify me

Front. Plant Sci. | doi: 10.3389/fpls.2019.01486

G65V substitution in actin disturbs polymerization leading to inhibited cell elongation in cotton

 Yongwang Sun1, Wenhua Liang1, Weijuan Shen1, Hao Feng1, Jiedan Chen2, Zhanfeng Si2, Yan Hu2 and  Tianzhen Zhang1*
  • 1Nanjing Agricultural University, China
  • 2Zhejiang University, China

The importance of the actin cytoskeleton for proper cell development has been well established in a variety of organisms. Actin protein sequences are highly conserved, and each amino acid residue may be essential for its function. In this study, we report the isolation and characterization of GhLi1 from an upland cotton mutant Ligon lintless-1 (Li1), which harbors the G65V substitution in its encoded actin protein. Li1 mutants exhibit pleiotropic malformed phenotypes, including dwarf plants, distorted organs, and extremely shortened fibers. Cytological analysis showed that the actin cytoskeleton was disorganized and the abundance of F-actin was decreased in the Li1 cells. Vesicles were aggregated into patches, and excessive cellulose synthase complexes were inserted into the plasma membrane during the secondary cell wall biosynthesis stage, which dramatically affected the morphology of the Li1 cells. Molecular model prediction suggested that the G65V substitution may affect the three-bodied G-actin interaction during F-actin assembly. Biochemical assays demonstrated that the recombinant GhLi1 protein disturbs actin dynamics by inhibiting the nucleation and elongation processes. Therefore, our findings demonstrate that the G65V substitution in actin had dominant-negative effects on cell elongation, by disturbing actin polymerization and actin cytoskeleton-based biological processes such as intracellular transportation.

Keywords: actin polymerization, cell elongation, Cotton, map-based cloning, Plant Morphology, Short fiber

Received: 04 Aug 2019; Accepted: 25 Oct 2019.

Copyright: © 2019 Sun, Liang, Shen, Feng, Chen, Si, Hu and Zhang. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

* Correspondence: Prof. Tianzhen Zhang, Nanjing Agricultural University, Nanjing, China, cotton@njau.edu.cn