Sugar Metabolism and Transport in Response to Drought–Rehydration in Poa pratensis

Poa pratensis is one of the world’s most widely planted cold-season turfgrasses, with good quality but poor drought resistance. When plants suffer from stress, the metabolism of soluble sugar takes place, which is a dynamic process involving both degradation and synthesis. A detailed and in-depth study of the sugar metabolism process in plants’ response to stress will help us to understand the internal mechanism of plant adaptation to stress. In this study, the ‘10-202’ ecotype with drought resistance and the ‘Blue moon’ ecotype with drought sensitivity were used to explore the sugar metabolism process in response to drought stress. The results showed that drought stress induced sucrose accumulation in the leaves and roots, promoted increases in SPS, S-AI, and PpN/A-Inv activities, as well as gene expression in the leaves, and changed the content and distribution of fructose, glucose, sucrose, maltose, and trehalose in vivo. Compared with ‘Blue moon’, ‘10-202’ had higher trehalose content in leaves under normal conditions, and its roots could accumulate more fructose and glucose to maintain the balance of osmotic potential and redox under drought stress. Meanwhile, PpSWEET1b, -12, and -15 in the leaves and roots of the two ecotypes were significantly induced by drought stress. The improvements in sucrose accumulation and decomposition efficiency in leaves under drought stress is conducive to enhancing drought resistance in plants. PpSWEET1b plays a vital role in regulating the sugar transport process of drought tolerance in turfgrass.