Abstract
To improve immune responses to the chitin elicitor (CE) in rice, we have constructed the chimeric receptor CRXA, which consists of a receptor for CE, CEBiP, and the intracellular kinase domain of XA21 that confers resistance to rice bacterial blight. Rice plants expressing CRXA increase cell death after treatment with CE and show more resistance to rice blast disease (Kishimoto et al., 2010). To test whether the combination of CEBiP and other types of receptor-like protein kinases (RLKs) works as a chimeric receptor, we constructed CRPi, which encodes ectodomain of CEBiP and the intracellular region of a homologue of R protein for rice blast identified in rice cultivar Nipponbare. Rice cultured cells expressing CRPi showed the increased level of oxidative burst after treatment with CE, but the level of cell death was not as much as in CRXA-expressing cells. Rice plants expressing CRPi showed more resistance to the blast fungus in leaf sheaths and blades. These results suggest that the fusion protein of CEBiP and the intracellular region of RLKs other than XA21 also works as a functional receptor leading to the enhancement of defense responses and resistance to rice blast.
