苹果果实糖分形成的分子基础OA

Apple is an important fruit widely cultivated worldwide.The soluble sugar content of the fruit is a core index determining its flavor quality and market competitiveness,and its accumulating process involves a complex genetic and molecular regulatory network.This paper systematically reviews the physiological basis,molecular mechanisms,and regulatory factors of sugar accumulation in apple fruits.At the physiological level,sugar accumulation relies on the coordinated action of multiple processes,including the synthesis,transport,unloading,metabolism,and vacuolar storage of photosynthates(mainly sorbitol and sucrose),which are mediated by key carriers such as sucrose transporters(SUTs),tonoplast sugar transporters(TSTs),and SWEET transporters.In terms of molecular mechanisms,sorbitol metabolism-related genes(MdS6PDH and MdSDH),sucrose metabolism-related genes(MdSuSy and MdSPS),and hexose metabolism-related genes(MdHXK and MdFRK)regulate the synthesis and conversion of different sugar components respectively;transcription factors such as MYB,bZIP,ERF,NAC,and WRKY accurately regulate the expression of sugar metabolism and transport-related genes by forming a complex regulatory network.In addition,plant hormones including auxin,abscisic acid,and ethylene participate in the regulation of sugar accumulation through cross-talk with sugar signals;environmental factors such as light,temperature,water,and nutrients affect the expression of related genes and enzyme activities through specific molecular pathways,thereby shaping the sugar characteristics of fruits.At present,issues such as the interaction of core regulatory factors,the mechanism of sugar component conversion,and the interaction between environmental factors and endogenous genes in apple sugar accumulation still need further exploration.This review provides a comprehensive reference for elucidating the genetic and molecular mechanisms of sugar accumulation in apple fruits,and is of great significance for promoting the molecular breeding process of apple quality improvement.