The endoglucanase gene LOC_Os09g23084 is involved in rice development and susceptibility to sheath rot disease

Sheath rot disease, caused by Sarocladium oryzae, is a severe problem in rice cultivation and can result in significant yield loss worldwide. In this study, we analyzed the function of LOC_Os09G23084, encoding an endoglucanase-1 precursor, through gene overexpression. Two single T-DNA insertion homozygous overexpression lines, 1-16 S and 4-10 S, derived from Oryza sativa cv. TNG67, were used for functional characterization. In field conditions, overexpression of LOC_Os09g23084 resulted in a decrease in rice development and an increase in susceptibility to sheath rot disease at the harvest stage. The overexpression lines showed delayed maturation, reduced internode and panicle neck length, deformed and less protruded vascular bundles, lower lignin content, and decreased yield. To verify the susceptibility of the overexpression lines to sheath rot disease, we set up a leaf-cutting inoculation method on seedlings. Lesion length was used to assess disease severity and was confirmed by fungal colonization using a GFP-tagged S. oryzae transgenic strain. The data confirmed that the overexpression lines were more susceptible to S. oryzae than wild-type lines. The reduced internode length and panicle neck length, less protruded peripheral vascular bundles, and low lignin content might contribute to the susceptibility to sheath rot. In this study, we provide insights into the potential function and mechanism of the endoglucanase gene LOC_Os09g23084 in rice susceptibility to sheath rot disease. Additionally, we demonstrated that LOC_Os09G23084 plays a crucial role in rice growth and development.