Genome-wide identification and characterization of R2R3-MYB genes in Medicago truncatula

Abstract

MYB is a large family of plant transcription factors. Its function has been identified in several plants, while there are few reports in Medicago truncatula. In this study, we used RNA-seq data to analyze and identify R2R3-MYB genes in the genome of Medicago truncatula. Phylogenetic analysis classified 150 MtMYB genes into 21 subfamilies with homologs. Out of the 150 MtMYB genes, 139 were distributed among 8 chromosomes, with tandem duplications (TD) and segment duplications (SD). Microarray data were used for functional analysis of the MtMYB genes during growth and developmental processes providing evidence for a role in tissues differentiation, seed development processes, and especially the nodulation process. Furthermore, we investigated the expression of MtMYB genes in response to abiotic stresses using RNA-seq data, which confirmed the critical roles in signal transduction and regulation processes under abiotic stress. We used quantitative real-time PCR (qRT-PCR) to validate expression profiles. The expression pattern of M. truncatula MYB genes under different abiotic stress conditions suggest that some may play a major role in cross-talk among different signal transduction pathways in response to abiotic stresses. Our study will serve as a foundation for future research into the molecular function of M. truncatula R2R3-MYB genes.

Genome-wide identification of R2R3-MYB family in wheat and functional characteristics of the abiotic stress responsive gene TaMYB344

“…The duplication events of MYB family also occurred in other plants, such as Medicago truncatula, Solanum tuberosum, Brassica napus, Gossypium raimondii etc. [16,18,27,28]. Most homologous chromosomes of hexaploid wheat (AABBDD) are collinear, while chromosomes 4A and 5A happened reciprocal translocations and pericentric inversion in the process of evolution [29].…”

The Pea R2R3-MYB Gene Family and Its Role in Anthocyanin Biosynthesis in Flowers

“…We searched for R2R3-MYB genes in 10 species ranging from lower aquatic plants to higher terrestrial plants to determine the origin of the R2R3-MYB gene ( Yanhui et al, 2006 ; Dubos et al, 2010 ; Du et al, 2012a ; He et al, 2016 ; Li et al, 2019 ; Jiang and Rao, 2020 ; Pu et al, 2020 ) According to this analysis, R2R3-MYB gene is present in all researched plant and there has been a tendency toward an increase in gene number over the course of plant evolution with a dramatically increase in angiosperms ( Figure 1B ), suggesting that the R2R3-MYB gene family is expanded during evolution to overcome the increased biological complexity.…”

MtGSTF7, a TT19-like GST gene, is essential for accumulation of anthocyanins, but not proanthocyanins in Medicago truncatula

“…Several studies have demonstrated that the regulation of anthocyanin accumulation in dicotyledons is conserved, and that the sixth sub-group of MYB TFs plays important roles in anthocyanin accumulation both spatially and temporally ( Zhang et al , 2014 ). In M. truncatula , there are 14 members of the sixth sub-group of MYB TFs ( Li et al , 2019 ), indicating that these paralogs might exhibit functional specialization or redundancy in the regulation of anthocyanin biosynthesis. Among those paralogs, apart from LAP1 which was identified by reverse genetics, the other three members, WP1, RH1 and RED HEART2 (RH2), have been demonstrated to participate in tissue specific-accumulation of anthocyanins ( Peel et al , 2009 ; Meng et al , 2019 ; Wang et al , 2021 ).…”