Elucidation of BiP-regulated Innate Immunity

University Of California-Davis, Davis CA

Investigators

Abstract

The rice receptor-like kinase, XA21, is a key recognition determinant in the innate immune response, a pathogen defense pathway widely conserved between plants and animals. Few proteins that transduce the rice innate immune response have been characterized. For this reason the isolation of a protein from an in vivo XA21 complex, called BiP (luminal binding protein, also called glucose regulated protein 78 (GRP78)), is particularly important. BiP is an endoplasmic reticulum (ER)-located member of the family of heat shock protein (HSP) 70 chaperones. In BiP3-overexpressing rice plants, XA21-mediated resistance is compromised and XA21 stability is significantly decreased. These results indicate that BiP3 regulates XA21 protein stability and processing and that this regulation is critical for resistance. The long-term goal of this project is to elucidate the mechanisms of innate immunity, determine the role of BiP in these signaling pathways, and use this information to develop new strategies for disease control in plants and animals. The project will use biochemical, cell biological and genetic approaches to determine how the ER chaperone BiP affects XA21-mediated signaling. Results from these studies will lead to major advances in understanding biogenesis and processing of plant and animal sensors of pathogen-derived molecules. Because XA21 is closely related to sensors controlling innate immunity in other plants and animals, the expected results will have a broad impact on understanding and controlling diseases of cereals and humans. The results will have relevance to other plant-microbe interactions and will be disseminated broadly to enhance scientific and technological understanding of the mechanisms of innate immunity. Postdoctoral and graduate students will receive training in bacterial genetics, biochemistry, and plant pathology. Educational outreach includes a month-long science and art program to be presented in a local elementary school.