Genome-Wide Comparative Analysis of the R2R3-MYB Gene Family in Five Solanaceae Species and Identification of Members Regulating Carotenoid Biosynthesis in Wolfberry.

Yue Yin,Hongyan Shi,Xiangqiang Zhan,Xinru He,Fang Ma,Wei An,Cong Guo,Youlong Cao,Jianhua Zhao,Qing Luo

doi:10.3390/ijms23042259

Abstract

The R2R3-MYB is a large gene family involved in various plant functions, including carotenoid biosynthesis. However, this gene family lacks a comprehensive analysis in wolfberry (Lycium barbarum L.) and other Solanaceae species. The recent sequencing of the wolfberry genome provides an opportunity for investigating the organization and evolutionary characteristics of R2R3-MYB genes in wolfberry and other Solanaceae species. A total of 610 R2R3-MYB genes were identified in five Solanaceae species, including 137 in wolfberry. The LbaR2R3-MYB genes were grouped into 31 subgroups based on phylogenetic analysis, conserved gene structures, and motif composition. Five groups only of Solanaceae R2R3-MYB genes were functionally divergent during evolution. Dispersed and whole duplication events are critical for expanding the R2R3-MYB gene family. There were 287 orthologous gene pairs between wolfberry and the other four selected Solanaceae species. RNA-seq analysis identified the expression level of LbaR2R3-MYB differential gene expression (DEGs) and carotenoid biosynthesis genes (CBGs) in fruit development stages. The highly expressed LbaR2R3-MYB genes are co-expressed with CBGs during fruit development. A quantitative Real-Time (qRT)-PCR verified seven selected candidate genes. Thus, Lba11g0183 and Lba02g01219 are candidate genes regulating carotenoid biosynthesis in wolfberry. This study elucidates the evolution and function of R2R3-MYB genes in wolfberry and the four Solanaceae species.

Highlights

Wolfberry (Lycium barbarum L., 2n = 2x = 24), of the genus Lycium within the Solanaceae family, is an important Chinese traditional herbal medicine [1]
The results indicate that two LbaR2R3-myeloblastosis viral oncogene homolog (MYB) genes probably regulate carotenoid metabolism
A total of 1326 MYB candidate genes were retrieved from the five Solanaceae species

Summary

Introduction

Wolfberry (Lycium barbarum L., 2n = 2x = 24), of the genus Lycium within the Solanaceae family, is an important Chinese traditional herbal medicine [1]. L. barbarum fruit colorations [5,6]. Fruit color is a key factor in wolfberry fruit quality. Fruit colorations involve complex biochemical changes due to genetic and environmental factors. Understanding the genetic factors controlling carotenoid accumulation is valuable to wolfberry breeding to generate novel fruit phenotypes. Carotenoid biosynthetic genes (CBGs) have been cloned and characterized in various plant species [7,8,9], including wolfberry. The transcriptional regulatory mechanisms of carotenoids in wolfberry are unclear

Methods

Results

Discussion

Conclusion