ABSTRACT
This study was aimed to discuss the dynamic variation of soluble sugar contents, sucrose metabolizing en-zyme activities and gene expression quantities during the fruits development of A momum villosum, in order to pro-vide the basis of improvement of the fruit yield. Fresh fruits at three different development processes (30 DAF, 60 DAF, 90 DAF) were used to investigate changes of soluble sugar components and sucrose metabolizing enzyme activ-ities by HPLC and UV spectrophotometry. Combining with the high-throughput sequencing expression profile data of three fruit development period, the trends of three key enzymes gene expressed in sugar metabolism were analyzed. The results showed that the fruit sugar components were dominated by fructose, glucose and sucrose. The concentra-tion of hexose (fructose and glucose) gradually decreased in peel. But in seeds the concentration of hexose decreased at first and then increased. The content of sucrose and the net activities of sucrose synthase (synthesizing direction minus decomposing direction) in peel and seeds were gradually increased. The expression trends of key enzyme gene in sugar metabolism examined by RNA-seq quantification showed that sucrose phosphate synthase and sucrose syn-thase gene increased and then kept constant, but the invertase gene expression trend was gradually rising. Conse-quently, sucrose synthase was the key enzyme catalyzing sucrose synthesis and decomposition. The activity of sucrose synthase and sucrose contents in peel and seeds reached the highest peak in the end of fruit mature.