Genome-wide Identification, Evolutionary and Functional Analyses of Kfb Family Members in Potato

Background: Kelch repeat F-box (KFB) proteins play vital roles in the regulation of multitudinous biochemical and physiological processes in plants, including growth and development, stress response and secondary metabolism. Multiple KFBs have been characterized in various plant species, but this family members have not been systematically identified and analyzed in potato. Results: Genome and transcriptome analyses of StKFB gene family were conducted to dissect the structure, evolution and function of the KFBs in Solanum tuberosum L. Totally, 44 StKFB members were identified and were classified into 5 groups according to their structural and phylogenetic features. The chromosomal localization analysis showed that the 44 StKFB genes were located on 12 chromosomes. Among these genes, two pairs of genes (StKFB15/16 and StKFB40/41) were predicted to be tandemly duplicated genes, and one pair of genes (StKFB15/29) was segmentally duplicated genes. The syntenic analysis showed that the KFBs in potato were closely related to the KFBs in tomato and pepper. Expression profiles of StKFBs in 13 different tissues and in potato plants with different treatments uncovered distinct spatial expression patterns of these genes and their potential roles in response to various stresses. Transcriptomic and qRT-PCR analyses of StKFBs deciphered that multiple StKFB genes were differentially expressed in three colored potato tubers. Genes that were highly expressed in yellow fleshed tubers (Jin-16) and were lowly expressed in the red- (Red Rose-2) or purple-fleshed (Xisen-8) tubers, such as StKFB07, StKFB15, StKFB23, StKFB29 and StKFB44, may negatively regulate anthocyanin biosynthesis.Conclusions: This study reports the structure, evolution and expression characteristics of the KFB family in potato. These findings set the stage for further study of functional mechanisms of StKFBs, and also provide candidate genes for potato genetic improvement.