Sucrose synthase is involved in the carbohydrate metabolism-based regulation of seed dormancy release in Pyrus calleryana Decne

Seed dormancy is an adaptation key to survival in conditions unsuitable for growth. In pear (Pyrus calleryana Decne), phytohormones participate in the release of seed dormancy. However, the involvement of carbohydrate metabolism in this process is still unclear. In the present study, we determined the sucrose, starch, and glucose levels during seed dormancy release. Sucrose and starch content decreased, whereas glucose levels increased. Consistent with these changes in carbohydrate content, the activity levels of sucrose synthase (SS) and α-amylase increased because they cleavaged sucrose and starch, respectively. In contrast, sucrose phosphate synthase (SPS) activity decreased during seed dormancy release. This latter enzyme catalyzes sucrose synthesis. Seed dormancy release was decreased during stratification in the presence of an antisense oligonucleotides (As-ODN) for PcaSS8. Moreover, sucrose levels increased and the activities of SS and α-amylase decreased during seed dormancy release after the treatment of As-ODN. Taken together, our results suggest that sucrose synthase plays an important role in regulating carbohydrate metabolism during seed dormancy release in P. calleryana.