Abstract
Plant pathogens secrete cell wall degrading enzymes (CWDEs) to degrade various components of the plant cell wall. Plants sense this cell wall damage as a mark of infection and induce immune responses. Little is known about the plant functions that are involved in the elaboration of cell wall damage-induced immune responses. Transcriptome analysis revealed that a rice receptor kinase, WALL-ASSOCIATED KINASE-LIKE 21 (OsWAKL21.2), is upregulated following treatment with either Xanthomonas oryzae pv. oryzae (Xoo, a bacterial pathogen) or LipA, a CWDE of Xoo. Downregulation of OsWAKL21.2 attenuates LipA mediated immune responses. Overexpression of OsWAKL21.2 in rice mimics LipA treatment mediated induction of immune responses and enhanced expression of defence related genes, indicating it could be involved in the perception of LipA induced cell wall damage in rice. OsWAKL21.2 is a dual function kinase having in-vitro kinase and guanylate cyclase activities. Ectopic expression of OsWAKL21.2 in Arabidopsis also activates plant immune responses. Interestingly, OsWAKL21.2 needs kinase activity to activate rice immune responses while in Arabidopsis it needs guanylate cyclase activity. Our study reveals a novel receptor kinase involved in elaboration of DAMP induced rice immune responses that can activate similar immune responses in two different species via two different mechanisms.
One sentence Summary A novel rice receptor WAKL21 that sense cell wall damage caused by Xanthomonas secreted cell wall degrading enzyme to induce immune responses.
Footnotes
Funding Information: This work was supported by the XIIth five-year plan project, Plant-Microbe and Soil Interactions (BSC0117) of the Council of Scientific and Industrial research and J. C. Bose fellowship to R.V.S. K.K.M. and A.R. acknowledge Council of Scientific & Industrial Research (CSIR), India for the fellowship.
The author responsible for distribution of materials integral to the findings presented in this article in accordance with the policy described in the Instructions for Authors (www.plantcell.org) is: Ramesh V. Sonti (sonti{at}ccmb.res.in)