Genome-Wide Identification and Expression Profiling Analysis of the Trihelix Gene Family Under Abiotic Stresses in Medicago truncatula.

Xiqiang Liu,Han Zhang,Kun Wang,Zan Wang,Lin Ma

doi:10.3390/genes11111389

Xiqiang Liu, Han Zhang + Show 3 more

Open Access

https://doi.org/10.3390/genes11111389

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Abstract

The trihelix transcription factor (GT) family is widely involved in regulating plant growth and development, and most importantly, responding to various abiotic stresses. Our study first reported the genome-wide identification and analysis of GT family genes in Medicago truncatula. Overall, 38 trihelix genes were identified in the M. truncatula genome and were classified into five subfamilies (GT-1, GT-2, SH4, GTγ and SIP1). We systematically analyzed the phylogenetic relationship, chromosomal distribution, tandem and segmental duplication events, gene structures and conserved motifs of MtGTs. Syntenic analysis revealed that trihelix family genes in M. truncatula had the most collinearity relationship with those in soybean followed by alfalfa, but very little collinearity with those in the maize and rice. Additionally, tissue-specific expression analysis of trihelix family genes suggested that they played various roles in the growth and development of specific tissues in M. truncatula. Moreover, the expression of some MtGT genes, such as MtGT19, MtGT20, MtGT22, and MtGT33, was dramatically induced by drought, salt, and ABA treatments, illustrating their vital roles in response to abiotic stresses. These findings are helpful for improving the comprehensive understanding of trihelix family; additionally, the study provides candidate genes for achieving the genetic improvement of stress resistance in legumes.

Highlights

Transcription factors (TFs) are a kind of DNA binding protein, that play pivotal roles in plant growth and development, as well as in response to environmental stresses [1,2]
We demonstrated the collinearity of MtGT genes with A. thaliana, G. max, Zea mays, O. sativa and M. sativa genomes
38 non-redundant trihelix genes were identified in the M. truncatula genome through two BLAST methods based on the known trihelix protein sequences of Arabidopsis, and both Pfam and Conserved Domain Database (CDD) databases confirmed the presence of trihelix domain

Summary

Introduction

Transcription factors (TFs) are a kind of DNA binding protein, that play pivotal roles in plant growth and development, as well as in response to environmental stresses [1,2]. Trihelix TF family members have attracted more attention; they feature a typical helix–loop–helix–loop–helix structure with a core sequence of 50 -G-Pu-(T/A)-A-A-(T/A)-30 in their DNA-binding domain [4,5]. Because this domain can bind to GT elements required for light response in a DNA sequence, it is called the GT family [6]. The conserved domain of trihelix is similar to the individual repeats of the MYB family in sequence; it is generally thought to be derived from MYB-like genes [5].

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