Pollen-Expressed Plant U-Box Protein, OsPUB14 Involves in Rice Fertility and Degrades OsMTD2

Understanding the intricacies of pollen tube growth in cereal crops, such as rice, is crucial for understanding crossbreeding, seed formation, and crop productivity. In this study, we investigated the molecular mechanisms underlying pollen tube germination and elongation in rice, focusing on the interaction between OsPUB14 and OsMTD2 and its impact on reactive oxygen species (ROS) regulation. Expression studies revealed that OsPUB14 was highly expressed in pollen and anther tissues, indicating its involvement in pollen function. We demonstrated that OsPUB14 belonging to group II U-box domain proteins, interacts with the kinase domain of OsMTD2 (a pollen-specific CrRLK1L member) and degrades it. This interaction subsequently reduces OsMTD2-mediated ROS generation. Moreover, the overexpression of OsPUB14 resulted in decreased ROS levels and reduced fertility in rice plants, emphasizing its role in reproductive processes. Yeast two-hybrid screening identified OsCRK10P and OsNET2D as potential interactors of OsPUB14, further expanding our understanding of the regulatory networks associated with pollen development. This study provides insight into the intricate interplay between pollen-specific plant U-box domain proteins (PUBs), demonstrating their roles in regulating ROS levels and ultimately influencing plant fertility.