Genome-Wide Analysis of Monosaccharide Transporter (MST) Family Genes in Pear

The monosaccharide transporter (MST) gene family plays an important role in plant growth and development. In this study, a total of 69 MST genes were identified in pear genome based on systematic analysis, the identified MST genes were grouped into seven subfamilies according to structural and phylogenetic analysis. The sequences of cis-regulatory elements of all MST genes indicated that the MYBCOREATCYCB1 promoter exclusively present in all MST genes of pear. Gene duplication event analysis indicated that whole genome duplication (WGD)/segmental duplication play a key role during MST gene amplification, accompanied by tandem duplications, especially for tonoplast monosaccharide transporters (tMT) subfamilies and Early-responsive to dehydration (ERD6-like) subfamilies. According to the global transcriptome sequencing of pear fruit, gene expression profile shows that the expression of 47 MSTs can be identified. Among them, 3 MST genes were expressed in developmental stage-specific manner during fruit development, and many genes may be candidate genes involved in improving fruit sugar content. Identification of fruit-specific MSTs might be a first step to finding novel genes contributing to pear fruit monosaccharide accumulation.