Pectate Lyase FvePL1 Is Required for Pollen Fertility and Mediates Drought Response in Woodland Strawberry

Successful fertilization is essential for fruit bearing and yield enhancement, relying on male gametophyte which facilitates sexual reproduction by transferring the sperm cell to the ovule. To accomplish this task, pectate lyase is secreted to lubricate the sperm cell towards the female partner by different strategies. However, the specific impact of strawberry PL in male sterility and achene development remained elusive. Here, we systematically investigated the functions of diploid strawberry Fragaria vesca pectate lyase 1 (FvePL1), determining its localization in the cell wall and membrane. In situ hybridization presented its maximum expression in the anther, particularly the endothecium, connective tissue, and septum. Analysis of RNAi mutants and green fluorescent protein (GFP)-tagged overexpression lines demonstrated that the failure of FvePL1 significantly inhibited the fruit set due to stunted achenes. In addition, the deficiency of FvePL1 expression resulted in a 68.29% reduction in the number of pollen grains, a 73.27% decrease in pollen viability, morphological alterations of exine and intine, impaired pollen tube, and the inability of the sperm nucleus to reach its target due to the delayed and incomplete tapetal degeneration. In addition, the suppression of FvePL1 resulted in a 65.02% increase in survival rate withholding irrigation for 30 days, conferring enhanced drought tolerance by negatively influencing cell wall structure. Therefore, this study identified FvePL1 as a crucial regulator of pollen development, fertilization, and achene maturation and abiotic stress. These findings provide a framework for advancing research on the development of the male gametophyte in strawberry and even yield optimization in Rosaceous crops.