Comparative Transcriptome Analysis Provides Insights into Fruit Trichome Development in Peach

Fruit pubescence (trichome) is an important characteristic and is controlled by a single dominant gene (G/g), resulting in peaches and nectarines. The length and/or density of fruit fuzz varies greatly among different peach cultivars. However, little is known about fruit trichome development in peaches. In this study, significant differences in fruit trichome length and density were identified between ‘XT1’ and its bud mutation ‘BM’, showing much higher values for ‘BM’. Comparative transcriptome analysis was performed, and 987 differentially expressed genes (DEGs) were identified, which were confirmed by qRT-PCR. GO (Gene Ontology) and KEGG (Kyoto Encyclopedia of Genes and Genomes) analyses showed that genes involved in defense response, secondary metabolites and plant hormone signal transduction may also be related to the development of peach fruit trichomes. By integrating other transcriptome data, we finally determined 47 DEGs that might participate in peach trichome development, including five plant-hormone-related genes. The promoter analysis showed that one abscisic-acid-related gene, Prupe.6G072400 (abscisic acid 8′-hydroxylase 2), and one auxin-related gene, Prupe.3G074900 (auxin-responsive protein IAA1), have obvious differences in the cis-acting elements of the promoters between ‘XT1’ and ‘BM’. The results of this study will provide a valuable resource illustrating the mechanism of fruit trichome development in peaches and benefit future genomic research.