Identification and expression profiling of sugar transporter genes during sugar accumulation at different stages of fruit development in apricot.

Sugars are considered as an essential signaling molecule for fruit growth and development, which plays a key role in fruit quality. Up to now, the mechanism controlling sugar metabolism and transport in apricot is unclear. Therefore, in the present study, we measured sugar contents at six different stages of fruit development and ripening, and significant variations were observed throughout these stages. The concentration of glucose and fructose first decreased then increased, sucrose concentration first increased then decreased, while the concentration of sorbitol gradually decreased from growth to maturity. Furthermore, thirty sugar transporter genes related to sucrose synthesis and transport were identified and categorized into different subfamilies based on the phylogenetic analysis. The result of cis-regulatory components showed that under different plant hormones, biotic and abiotic stresses, few elements could be regulated. The correlation analysis showed a higher relationship between ParSuSy5, ParSuSy6, ParSuSy7, and ParFK1 genes and sugar contents, indicating that these genes might have a key role in sugar accumulation and fruit quality. In general, these findings will provide a deep understanding of genomic information and expression profiles of sugar transporter genes, which will contribute toward improvement in fruit quality of apricot.