Genomic characterisation, phylogenetic comparison and candidate gene identification of the lipid transfer proteins gene family in pear (Pyrus bretschneideri Rehd.) and other Rosaceae species

Plant non-specific lipid transfer proteins (nsLTPs) are a group of small, cryptic proteins that can reversibly bind and transport hydrophobic molecules. Studies have shown that nsLTPs can play important roles in various plant physiological processes, such as the transport of cuticular lipids, cutin synthesis, pathogen defence and abiotic stress responses. To date, a comprehensive analysis of the nsLTP gene family is still lacking in pear and other sequenced Rosaceae species. Here, 338 nsLTP genes were identified in eight Rosaceae fruit species, including 58 nsLTPs in Chinese white pear. The nsLTP family genes could be divided into four groups based on a detailed phylogenetic analysis and classification criteria in model plants. Multiple characteristics of 58 nsLTP genes in Chinese white pear were analysed, including their phylogeny, conserved motifs, chromosome locations, and cis-elements in the promoter sequences. Based on both RNA-Seq and qRT-PCR analyses, it was predicted that Pbr041771.1 might participate in cuticular wax translocation. The subcellular localisation results showed that Pbr041771.1 was localised in the plasma membrane. All results provide valuable information enhancing our understanding of the evolution and functional roles of nsLTP family genes.