SPL36 encodes a receptor-like protein kinase precursor and regulates programmed cell death and defense responses in rice

The rice (Oryza sativa) spotted leaf 36 (spl36) mutant was identified from an ethyl methanesulfonate–mutagenized Japonica cultivar Yundao population and was previously shown to display a spontaneous cell death phenotype and enhanced resistance to rice bacterial pathogens. Through the analysis of the expression of related genes, we speculate that spl36 is involved in the disease response by up-regulating the expression of defense-related genes. The results of physiological and biochemical experiments indicated that more cell death occurred in the mutant spl36, and the growth and development of the plant were affected. We have isolated SPL36 via a map-based cloning strategy. A single base substitution was detected in spl36, which results in encoding amino acid changes in the SPL36 protein. The predicted SPL36 encodes a receptor-like protein kinase precursor that contains repeated leucine domains and may be involved in stress response of rice. In the salt treatment experiment, we found that the mutant spl36 showed sensitivity to salt. Therefore, SPL36 may negatively regulate salt stress-related responses.