Transcriptome analysis of photosynthetic adaptation in peach rootstock leaves under waterlogging stress

Waterlogging is a severe abiotic stress that is occurring with increasing frequency worldwide, and may cause crop yield declines. However, the molecular mechanisms of waterlogging responses in peach rootstock are poorly understood. In this study, we employed transcriptional profiling to explore the response status under waterlogging and gene response patterns during the recovery period in peach rootstock 'Baisha'. There were differences in photosynthetic metabolism responses between the non-waterlogging and continuous waterlogging stages. Compared with the control group, the differentially expressed gene (DEG) number increased along with waterlogging time. However, the DEG number decreased 12 d after starting treatment (AST) to less than the number at 4 d after terminating treatment (ATT). In total, 3,960 DEGs were identified after a comparative analysis of 12 d AST and 4 d ATT. A gene ontology analysis annotated 49 terms, including cellular process, metabolic process, cell part, membrane, catalytic activity and transcript activity. In total, 303 metabolic pathways were identified by KEGG analysis, among which photosynthesis and photosynthesisantennal protein pathways were significantly enriched. Although the core proteins D1 and D2 in the Photosystem II complex were not significantly changed, other proteins in Photosystems I and II were significantly downregulated. In addition, as time increased, the cytochrome, photosynthesis electron transport chain and active ATP enzyme factors decreased AST, while opposite trends occurred ATT. Thus, peach leaves have different response patterns under waterlogging and recovery conditions. The factors sensitive to stress and recovery were the cytochrome, photosynthesis electron transport chain and most active ATP enzyme factors in the photosynthesis metabolism process.