Genome wide identification of StKNOX gene family and characterization of their expression in Solanum tuberosum

The KNOTTED1-LIKE HOMEOBOX (KNOX) transcription factors (TF) play an important role in growth and developmental stages in potato. However, only few reports are available regarding the KNOX gene family in potato. In this study, 17 KNOX genes were detected in the potato genome. The gene structure, protein characteristics, promoter analysis, synthetic regions, gene duplication, gene expression in developmental stages, and chromosomal location were investigated. Based on their phylogenetic relationships, the StKNOX family members were categorized into three classes. Analysis of gene expression showed that the tissue expression patterns of StKNOX genes in the same group were similar but varied among groups. Analysis of transcription factor binding site (TFBS) and microRNA in the promoter region and coding sequence of StKNOX genes revealed the presence of putative TFBS and 49 StmiRNAs. Moreover, variable frequencies of TFSB and miRNA in StKNOX genes could indicate that these genes control different developmental stages and are involved in complex regulatory mechanisms. Our results showed that some members of Class II (StKNOX14) have the highest number of TFBS and are highly expressed in 19 potato tissues. Our findings showed that these genes could be involved in the regulation of plant growth and tuber development in S.tuberosum. The results of this study will be useful in further investigations on the functional role of potato StKNOX genes.