Overexpression of the persimmon ABA receptor DkPYL3 gene alters fruit development and ripening in transgenic tomato

Abstract

Abscisic acid (ABA) is a crucial plant hormone that regulates various aspects of plant development. However, the specific function of the ABA receptor PYL in fruit development has not been fully understood. In this study, we focused on DkPYL3, a member of the ABA receptor subfamily Ⅰ in persimmon, which exhibited high expression levels in fruit, particularly during the young fruit and turning stages. Through yeast two-hybrid (Y2H), firefly luciferase complementation imaging (LCI), protein inhibition assays, and RNA-seq techniques, we identified and characterized the DkPYL3 protein, which was found to inhibit the activity of protein phosphatase type 2 C (PP2C). By heterologous overexpressing (OE) persimmon DkPYL3 in tomatoes, we investigated the impact of the DkPYL3 gene on fruit development and ripening. DkPYL3-OE upregulated the expression of genes related to chlorophyll synthesis and development, leading to a significant increase in chlorophyll content in young fruit. Several fruit quality parameters were also affected by DkPYL3 expression, including sugar content, single fruit weight, and photosynthesis rate. Additionally, fruits overexpressing DkPYL3 exhibited earlier ripening and higher levels of carotenoids and flavonoids compared to wild-type fruits. These results demonstrate the pivotal role of DkPYL3 in ABA-mediated young fruit development, ripening onset, and fruit quality in transgenic tomatoes.