Zhou Q, Jia C, Ma W, Cui Y, Jin X, Luo D, Min X, Liu Z.

PeerJ. 2019 Sep 17;7:e7714. doi: 10.7717/peerj.7714. eCollection 2019.

Abstract

BACKGROUND:

Alfalfa is the most widely cultivated forage legume and one of the most economically valuable crops in the world. Its survival and production are often hampered by environmental changes. However, there are few studies on stress-resistance genes in alfalfa because of its incomplete genomic information and rare expression profile data. The MYB proteins are characterized by a highly conserved DNA-binding domain, which is large, functionally diverse, and represented in all eukaryotes. The role of MYB proteins in plant development is essential; they function in diverse biological processes, including stress and defense responses, and seed and floral development. Studies on the MYB gene family have been reported in several species, but they have not been comprehensively analyzed in alfalfa.

METHODS:

To identify more comprehensive MYB transcription factor family genes, the sequences of 168 Arabidopsis thaliana, 430 Glycine max, 185 Medicago truncatula, and 130 Oryza sativa MYB proteins were downloaded from the Plant Transcription Factor Database. These sequences were used as queries in a BLAST search against the M. sativa proteome sequences provided by the Noble Research Institute.

RESULTS:

In the present study, a total of 265 MsMYB proteins were obtained, including 50 R1-MYB, 186 R2R3-MYB, 26 R1R2R3-MYB, and three atypical-MYB proteins. These predicted MsMYB proteins were divided into 12 subgroups by phylogenetic analysis, and gene ontology (GO) analysis indicated that most of the MsMYB genes are involved in various biological processes. The expression profiles and quantitative real-time PCR analysis indicated that some MsMYB genes might play a crucial role in the response to abiotic stresses. Additionally, a total of 170 and 914 predicted protein-protein and protein-DNA interactions were obtained, respectively. The interactions between MsMYB043 and MSAD320162, MsMYB253 and MSAD320162, and MsMYB253 and MSAD308489 were confirmed by a yeast two-hybrid system. This work provides information on the MYB family in alfalfa that was previously lacking and might promote the cultivation of stress-resistant alfalfa.

See https://www.ncbi.nlm.nih.gov/pubmed/31576246

Figure 1:

Phylogenetic analysis and subgroup classifications of 265 MsMYB proteins and 45 MYB proteins from Arabidopsis thaliana, Lotus japonicus and Medicago truncatula.

The red, filled triangle denotes MYB genes in alfalfa; the blue, inverted triangle denotes MYB genes in A. thaliana; the green square denotes MYB genes in M. truncatula; and the purple diamond denotes MYB genes in L. japonicus. The genes in subgroups A, D, E, and G mainly respond to plant hormones; the genes in subgroups C and K mainly respond to abiotic stresses and plant hormones; the genes in subgroups A and B participate in the synthesis of secondary metabolites; the genes in subgroups F, I, and J participate in the development process; the genes in subgroup H respond to abiotic stresses and plant hormones, and participate in the development process; and the genes in subgroup L are only involved in transcriptional regulation.