Unlocking the rice immune system
Lawrence Berkeley National Laboratory
Rice is a staple for half the world’s population and the model plant for grass-type biofuel feedstocks. The research team discovered that a tyrosine-sulfated bacterial protein called RaxX, activates the rice immune receptor protein called XA21. This activation triggers an immune response against Xanthomonas oryzaepv.oryzae (Xoo), a pathogen that causes bacterial blight, a serious disease of rice crops. Our results show that RaxX, a small, previously undescribed bacterial protein, is required for activation of XA21-mediated immunity to Xoo, says Pamela Ronald, a plant geneticist for both JBEI and UC Davis who led this study. In 2009, Ronald and her group identified a small bacterial protein they named Ax21 as the molecular key that binds to the XA21 receptor to activate a rice plant’s immune response.