Transcriptome analysis reveals gene associated with fruit size during fruit development in pear

Abstract

Fruit size, one of the crucial traits of fruit, affects pear fruit quality. Usually, both velocity and duration of swelling determines fruit size. However, fruit enlargement studies involving gene regulation during pear fruit development are very limited. In this study, fruit weight, transverse and longitudinal diameters, fruit core, and flesh volume were measured. Cell sizes were presented by paraffin sections, and the number of cells was counted from fruitlet to mature fruit of the CG, XQ, and HS cultivars. Results revealed that pear fruit enlargement was a single sigmoid pattern and was determined by cell number and cell size during fruit development. In addition, transcriptome sequencing was conducted for the fruitlet, early enlargement, late enlargement, and ripening stages. By analyzing the Venn diagram, 156 and 186 differentially expressed genes (DEGs) were selected and identified for the early and late enlargement of pear fruit, respectively. Of these genes, we performed to analysis of gene function annotation and chromosome location. Furthermore, 14 DEGs were located in the reported quantitative trait locus (QTL) regions associated with pear fruit size. Taken together, the results of this study provide information on fruit size from transcriptome analysis and the potential molecular mechanism of candidate genes regulating fruit size in pear.