Integrated QTL mapping and transcriptomic profiling elucidate molecular determinants of sucrose accumulation in apricot (Prunus armeniaca L)

Apricot is a commercially vital stone fruit prized for its distinctive organoleptic characteristics and nutritional value. We developed an F1 population from ‘Chuanzhihong’ × ‘Luotuohuang’ to investigate the genetic basis of sugar metabolism. Whole-genome resequencing identified 63,162 high-quality InDel markers, while metabolomic profiling quantified soluble sugars (sucrose, glucose, fructose) across fruit developmental stages. Continuous variation in sugar accumulation patterns indicated polygenic inheritance. A high-density genetic map (601.5 cM, 0.44 cM average interval) revealed 20 stable QTLs across 8 linkage groups, explaining 8.0-16.2% phenotypic variance for individual and total sugars. WGCNA identified sugar component-specific modules showing strong correlations (r=0.57-0.95). Integrative analysis prioritized PA08G27233 as a hub gene within QTL intervals, encoding a SWEET transporter (designated PaSWEET1 ) with evolutionary conservation to AtSWEET1. This study elucidates molecular mechanisms of photoassimilate partitioning in apricot and provides genomic resources (high-resolution map, candidate genes) for marker-assisted breeding. The findings advance functional characterization of sugar metabolism pathways in Prunus species. • High-density genetic map construction and QTL discovery • Multi-omics integration reveals sugar-associated gene modules • Identification of a SWEET transporter hub gene • Polygenic inheritance model for sugar accumulation • Multifaceted insights into sugar metabolism and crop improvement