Genomic Analysis of Sugar Transporter Gene Family in Cultivated Peanut (Arachis Hypogaea): Evolution, Expression Profiles and Gene Variation

Abstract BackgroundSugar transporter (STP) gene family, belonging to the major facilitator superfamily, plays significant roles in monosaccharide distribution and many aspects of physiological processes. However, little information was available about the STP genes in cultivated peanut (Arachis hypogaea), an important edible and oil crop. The recent release of the whole-genome sequence of cultivated peanut allowed us to perform a genome-wide investigation into the phylogeny and expression profiling of peanut STP genes.ResultsA total of thirty-six STP genes containing the Sugar_tr conserved motifs were identified from the A. hypogaea genome and all the genes were renamed on the basis of their respective chromosome distribution. According to their phylogenetic features, the STPs were classified into four groups. The structure of the STP genes and their encoded proteins were examined. Synteny analysis and phylogenetic comparison of the STP genes provided deep insight into the evolutionary characteristics of peanut STP genes. The segmental duplication events played a major role in the expansion of the peanut STP gene family and homeologous chromosomes rearrangement may lead to the exchange of STP genes between the A and B sub-genome. Expression profiles derived from transcriptome data exhibited distinct expression patterns of AhSTP genes in various tissues. Among them, four AhSTP genes, AhSTP3, AhSTP9, AhSTP19, AhSTP28, exhibited high expression in early stage of pod formulate in subsp. hypogaea, and in developing phase of seed in subsp. fastigiate, suggesting these genes may be involved in the development of pod and seed. Gene variation analysis of the four genes utilizing the subspecies genome sequences indicated multiple variations occurred in gene sequence or promoter region, and provided valuable clues for the different expression profiles of the four genes during seed development in subsp. hypogaea and subsp. fastigiate.ConclusionThirty-six STP genes were identified in cultivated peanut and their protein character,structure,evolution characteristics, expression patterns and gene variation were analyzed.This study provided a foundation for further functional characterization of STP genes with an aim of cultivated peanut crop improvement.