Rice Lectin Protein r40c1 Interacts With Magnaporthe oryzae Sho1 Protein to Regulate Leaf Blast Resistance.

Lectins are known to play vital roles in biotic and abiotic stress tolerance in plants. Earlier, it was demonstrated that Osr40c1, a member of OsR40 lectin family, imparts osmotic stress tolerance in rice. However, how it renders resistance against pathogen attack remained unexplored. In this study, we deciphered the biotic stress responsive role of Osr40c1 protein against the leaf blast disease in rice. During disease development, Osr40c1 gene expression was upregulated up to 2 days-post inoculation while it dropped with disease progression. Further, Osr40c1 overexpressing plants exhibited enhanced resistance against pathogen attack. In silico analysis predicted an interaction between Osr40c1 and Mosho1, a Magnaporthe oryzae plasma membrane protein known to act as an osmosensor under high osmolarity and starvation. In-depth analysis revealed that the ARG-201 amino acid residue of C-terminal domain of Osr40c1 interacts with C-terminal domain of MoSho1. Next, to identify the biological relevance of this interaction, plants overexpressing individual domains of Osr40c1 were challenged by M. oryzae and their resistance levels were compared. Plants overexpressing the C-terminal domain of Osr40c1 containing the ARG-201 residue exhibited enhanced disease resistance compared to others. Together, our study highlights the novel role of Osr40c1 in regulating leaf blast disease resistance in rice.