Physiological and Transcriptional Responses of Grapevine Rootstocks to Waterlogging Stress

The physiological and molecular mechanisms underlying waterlogging tolerance in grapevine rootstocks are poorly understood. This study aimed to investigate the growth responses, protective enzyme activities, endogenous hormone levels, and associated gene expression in grapevine rootstocks under waterlogging stress. ‘SO4’ grape rootstock plants were subjected to waterlogging for 2, 14, and 27 days. Conventionally cultivated plants served as controls. Waterlogging stress increased the contents of H 2 O 2 , malondialdehyde, and indole-3-butyric acid (IBA) as well as the activities of superoxide dismutase (SOD), catalase (CAT), glutathione reductase (GR), and succinate dehydrogenase (SDH) in the leaves. In contrast, it reduced chlorophyll and carotenoid levels as well as the jasmonic acid content. Additionally, ascorbate peroxidase and nicotinamide adenine dinucleotide-dependent malate dehydrogenase enzyme activities decreased after 2 days of waterlogging but increased by day 27. The contents of methyl jasmonate and abscisic acid increased at 14 days but declined by day 27. At the molecular level, waterlogging stress induced upregulation of genes such as MnSOD , SDH , TAM , LOX , AOS3 , and DAD1 and suppressed the expression of ADH1 , YUCCA4 , and ZEP . These findings suggest that waterlogging tolerance in grape rootstocks may be associated with elevated IBA content, enhanced activities of SOD, CAT, GR, and SDH, and upregulated expression of genes including MnSOD , SDH , TAM , and DAD1 .