Genome-wide Identification and Analysis of Non-specific Lipid Transfer Proteins in Hexaploid Wheat

Non-specific Lipid Transfer Proteins (nsLTPs) are involved in numerous biological processes. To date, only a fraction of wheat (Triticum aestivum L.) nsLTPs (TaLTPs) have been identified, and even fewer have been functionally analysed. In this study, the identification, classification, phylogenetic reconstruction, chromosome distribution, functional annotation and expression profiles of TaLTPs were analysed. 461 putative TaLTPs were identified from the wheat genome and classified into five types (1, 2, C, D and G). Phylogenetic analysis of the TaLTPs along with nsLTPs from Arabidopsis thaliana and rice, showed that all five types were shared across species, however, some type 2 TaLTPs formed wheat-specific clades. Gene duplication analysis indicated that tandem duplications contributed to the expansion of this gene family in wheat. Analysis of RNA sequencing data showed that TaLTPs were expressed in most tissues and stages of wheat development. Further, we refined the expression profile of anther-enriched expressed genes, and identified potential cis-elements regulating their expression specificity. This analysis provides a valuable resource towards elucidating the function of TaLTP family members during wheat development, aids our understanding of the evolution and expansion of the TaLTP gene family and, additionally, provides new information for developing wheat male-sterile lines with application to hybrid breeding.