A β-ketoacyl-CoA synthase encoded by DDP1 controls rice anther dehiscence and pollen fertility by maintaining lipid homeostasis in the tapetum.

Key message: DDP1, encoding a β-Ketoacyl-CoA Synthase, regulates rice anther dehiscence and pollen fertility by affecting the deposition of lipid on anther epidermis and pollen wall. Anther dehiscence and pollen fertility are crucial for male fertility in rice. Here, we studied the function of Defective in Dehiscence and Pollen1 (DDP1), a novel member of the KCS family in rice, in regulating anther dehiscence and pollen fertility. DDP1 encodes an endoplasmic reticulum (ER)-localized protein and is ubiquitously expressed in various organs, predominately in the microspores and tapetum. The ddp1 mutant exhibited partial male sterility attributed to defective anther dehiscence and pollen fertility, which was notably distinct from those observed in Arabidopsis thaliana and rice mutants associated with lipid metabolism. Mutations of DDP1 altered the content and composition of wax on anther epidermis and pollen wall, causing abnormalities in their morphology. Moreover, genes implicated in lipid metabolism, pollen development, and anther dehiscence exhibited significantly altered expression levels in the ddp1 mutant. These findings indicate that DDP1 controls anther dehiscence and pollen fertility to ensure normal male development by modulating lipid homeostasis in the tapetum, thereby enhancing our understanding of the mechanisms underlying rice anther dehiscence and pollen fertility.