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Front. Plant Sci. | doi: 10.3389/fpls.2019.00016

A new allele of the sPIKE1 locus reveals distinct regulation of trichome and pavement cell development and plant growth

  • 1Northwest A&F University, China

The single-celled trichomes of Arabidopsis thaliana have long served as an elegant model for elucidating the mechanisms of cell differentiation and morphogenesis due to their unique growth patterns. To identify new components in the genetic network that governs trichome development, we carried out exhaustive screens for additional Arabidopsis mutants with altered trichome morphology. Here we report one mutant, aberrantly branched trichome1-1 (abt1-1), with a reduced trichome branching phenotype. After positional cloning, a point mutation in the SPIKE1 (SPK1) gene was identified in abt1-1. Further genetic complementation experiments confirmed that abt1-1 is a new allele of SPK1, so abt1-1 was renamed as spk1-7 according to the literatures. spk1-7 and two other spk1 mutant alleles, covering a spectrum of phenotypic severity, highlighted the distinct responses of developmental programs to different SPK1 mutations. Although null spk1 mutants are lethal and show defects in plant stature, trichome and epidermal pavement cell development, only trichome branching is affected in spk1-7. Surprisingly, we found that SPK1 is involved in the positioning of nuclei in the trichome cells. Lastly, through double mutant analysis, we found the coordinated regulation of trichome branching between SPK1 and two other trichome branching regulators, ANGUSTIFOLIA (AN) and ZWICHEL (ZWI). SPK1 might serve for the precise positioning of trichome nuclei, while AN and ZWI contribute to the formation of branch points through governing the cMTs dynamics. In summary, this study presented a fully viable new mutant allele of SPK1 and shed new light on the regulation of trichome branching and other developmental processes by SPK1.

Keywords: branching, cell morphogenesis, Cytoskeleton, Nucleus positioning, SPIKE1, Trichome

Received: 22 Aug 2018; Accepted: 08 Jan 2019.

Edited by:

Taku Takahashi, Okayama University, Japan

Reviewed by:

John Larkin, Department of Biological Sciences, Louisiana State University, United States
Mitsutomo Abe, The University of Tokyo, Japan  

Copyright: © 2019 Liang, Yang, Zhao, Shao, Qi, Liu, An and Yu. 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:
Dr. Lijun An, Northwest A&F University, Yangling, China, lijunan@nwsuaf.edu.cn
Prof. Fei Yu, Northwest A&F University, Yangling, China, flyfeiyu@gmail.com