Characterization of a Rice GH5_11 Gene Associated with Endosperm and Seed Traits

The plant cell wall is essential for maintaining cellular structure and regulating physiological processes such as growth and stress tolerance. Cell wall dynamics are largely mediated by cell wall-modifying enzymes, including glycoside hydrolases (GHs). In this study, we explored GH5 family members in Oryza sativa L. and identified 17 genes encoding GH5 proteins, classified into three subfamilies: GH5_7, GH5_11, and GH5_14. Characterization of the GH5_11 protein encoded by the LOC_Os04g40510 gene involved the subcellular localization of a GFP-tagged protein, gene expression analysis during germination, and phenotypic evaluation of transgenic plants. The protein was synthesized through the secretory pathway with expression in seeds, predominantly in the endosperm. Overexpression of LOC_Os04g40510 resulted in altered seed morphology, increased chalkiness, and reduced seed set. Although the overall seed number increased, the seed mass was reduced for the knock-down lines. These data suggest that LOC_Os04g40510 may play a role in fertility and endosperm development. Our findings provide new insights into the biological function of GH5_11 enzymes in rice.