Sucrose accumulation and key sucrose synthase gene screening in ‘early beauty’ plum fruit across different developmental stages

• It was found that sucrose is the main soluble sugar in ‘Early Beauty’ plum fruit during maturation. • The critical period for sucrose accumulation in ‘Early Beauty’ plum fruit was identified, specifically from 59 DAFB to 66 DAFB. • PsSS1 was identified as a key gene in sucrose metabolism in ‘Early Beauty’plum. • Through transient transformation technology, it was verified that the silencing and overexpression of PsSS1 significantly affected the sucrose content. ‘Early Beauty’ is an elite early-maturing plum (Prunus salicina L.) cultivar. However, the dynamic changes in sucrose accumulation and the key regulatory genes involved in sucrose biosynthesis remain largely unknown. In this study, high-resolution spatiotemporal datasets were obtained using GC–MS/MS combined with RNA-seq to systematically investigate the dynamics of sucrose metabolism and transcriptional landscapes in ‘Early Beauty’ plum fruit throughout development. The results revealed that sucrose is the predominant soluble sugar at fruit maturity, with the period from 59 to 66 DAFB identified as the critical phase for sucrose accumulation. The PsSY0025487 was selected for further study using RNA-seq. Phylogenetic analysis showed highest homology to peach PpSS1, designated it PsSS1. Overexpression of PsSS1 increased sucrose content by 85.6 % (from 23.71 to 44.02 mg/g), while silencing reduced it by approximately 42 %, demonstrating its critical role in sucrose accumulation. This study not only elucidates the spatiotemporal patterns of sucrose metabolism in ‘Early Beauty plum, but supports metabolic regulatory research in plum and other fruit crops.