Genome-Wide Analysis of the COBRA-Like Gene Family Supports Gene Expansion through Whole-Genome Duplication in Soybean (Glycine max).

Sara Sangi,Fernanda S Coelho,Paula M Araújo,Rajesh K Gazara,Fabrício Almeida-Silva,Thiago M Venancio,Clicia Grativol

doi:10.3390/plants10010167

Sara Sangi, Fernanda S Coelho + Show 5 more

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https://doi.org/10.3390/plants10010167

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Abstract

The COBRA-like (COBL) gene family has been associated with the regulation of cell wall expansion and cellulose deposition. COBL mutants result in reduced levels and disorganized deposition of cellulose causing defects in the cell wall and inhibiting plant development. In this study, we report the identification of 24 COBL genes (GmCOBL) in the soybean genome. Phylogenetic analysis revealed that the COBL proteins are divided into two groups, which differ by about 170 amino acids in the N-terminal region. The GmCOBL genes were heterogeneously distributed in 14 of the 20 soybean chromosomes. This study showed that segmental duplication has contributed significantly to the expansion of the COBL family in soybean during all Glycine-specific whole-genome duplication events. The expression profile revealed that the expression of the paralogous genes is highly variable between organs and tissues of the plant. Only 20% of the paralogous gene pairs showed similar expression patterns. The high expression levels of some GmCOBLs suggest they are likely essential for regulating cell expansion during the whole soybean life cycle. Our comprehensive overview of the COBL gene family in soybean provides useful information for further understanding the evolution and diversification of COBL genes in soybean.

Highlights

The plant cell wall is a dynamic network that provides mechanical support, determines the cell shape, and controls the cell expansion [1]
Using BLASTp (Basic Local Alignment Search Tool algorithms) and HMM (Hidden Markov Model) profile search, we found a total of 24 COBL genes in the soybean genome version 2, which were designated as GmCOBL1 to GmCOBL24, according to their chromosomal locations (Table 1)
COBL genes are necessary for cellular expansion [9,10], grain yield [26] and are required for cellulose synthesis [8]

Summary

Introduction

The plant cell wall is a dynamic network that provides mechanical support, determines the cell shape, and controls the cell expansion [1]. The primary cell wall surrounds the entire cell, providing physical strength and extensibility to allow cell expansion, and plant growth [2]. The secondary cell wall is formed, and provides resistance to the tissues of the plant [3]. The cell shape and direction of cell expansion is, in part, controlled by the orientation of cellulose microfibrils [4]. Cellulose microfibrils consist of β (1–4)-linked glucan residue chains and form the major component of the cell wall [5]. Cellulose provides higher rigidity and extensibility to the cell wall. Members of the cellulose synthase A (CesA) gene family encode glycosyltransferases that play a key role in rosette synthesis [6,7]

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