Abstract: 【Objective】 Soybean seed is susceptible to high temperature and humidity (HTH) stress resulting in pre-harvest deterioration during its development and maturation (R6 or R7), which limits the production and utilization of soybean in south China. The aim of the present study is to reveal the pre-harvest seed deterioration and deterioration resistance mechanism of spring soybean under HTH stress at proteomic level, thus laying a foundation for breeding new cultivars.【Method】When the deterioration-sensitive cultivar Ningzhen No.1 and deterioration-tolerant cultivar Xiangdou No.3 developed to physiological period (R7), their plants were treated under HTH stress and control for 1, 5, 10, 16 and 24 h, respectively. The extracted proteins from the developing seed of treatment and control were analyzed by two-dimensional electrophoresis (2-DE), and the differentially expressed proteins were identified by MALDI-TOF/TOF. 【Result】Approximately 700 protein spots were detected on each 2-DE gel. Of them, 50 were found to be significantly changed in abundance, with 33 being successfully identified by MALDI-TOF/TOF. The identified differentially expressed proteins were involved in cell rescue and defense (9%), redox homeostasis (12%), protein synthesis (3%), energy metabolism (15%), transport pathway (15%), protein destination and storage (31%). Moreover, the function of 5 identified proteins is unknown. 【Conclusion】Pre-harvest deterioration-resistant cultivar Xiangdou No.3 possessed the greater ability of ROS scavenging and cell rescue and defense than deterioration-sensitive cultivar Ningzhen No.1 under HTH tress, which may be the major reasons why it is more deterioration-resistant than the latter.

Key words: spring soybean seed, pre-harvest seed deterioration, deterioration resistance, high temperature and humidity, proteomics