Combining Physiology and Transcriptome Data Screening for Key Genes in Actinidia arguta Response to Waterlogging Stress

Actinidia arguta is a cold-resistant fruit tree but intolerant to waterlogging. Waterlogging stress is the major abiotic stress in A. arguta growth, and several pathways are involved in the response mechanisms. Fifteen physiological indices and transcriptome data of two A. arguta cultivars, which showed two forms under waterlogging, were used to identify the major factor following the leaf senescence in waterlogging. Through principal component analysis (PCA) of 15 physiological indices in ‘Kuilv’ and ‘Lvwang’, the hormone contents were selected as the most important principal component (PCA 2) out of four components in response to waterlogging stress. According to the analysis of transcriptome data, 21,750 differentially expressed genes were identified and 10 genes through WGCNA, including hormone metabolism and sucrose metabolism, were screened out on the 6th day of waterlogging. In particular, the ABA signal transduction pathway was found to be closely related to the response to waterlogging based on the correlation analysis between gene expression level and plant hormone content, which may have regulated physiological indicators and morphological changes together with other hormones. Overall, the phenomenon of leaves falling induced by ABA might be a protective mechanism. The results provided more insights into the response mechanism of coping with waterlogging stress in A. arguta.