Interkingdom chemical crosstalk across the plant-microbe interface during Rice Blast
N. NAQVI (1), R. Patkar (1), Z. Qu (1), F. Yang (1) (1) Temasek Life Sciences Laboratory, Singapore

Rice Blast represents a model pathosystem, wherein the causal fungus, Magnaporthe oryzae, utilizes appressoria to breach the host cuticle. Typically, a biotrophic phase precedes necrotrophy in Magnaporthe-rice interaction and disease development. We identified a novel Antibiotic Biosynthesis Monooxygenase (ABM) that is essential for Magnaporthe pathogenesis. Magnaporthe likely acquired ABM through horizontal gene transfer from rhizosphere microbiota. Loss of ABM led to precocious activation of the host defense response in rice. Thus, the Abm monooxygenase activity is essential for suppressing the innate immunity in invaded rice cells and plays an important role in the biotrophy to necrotrophy transition. Abm and its major product, 12-Hydroxyjasmonic Acid, are directly involved in suppressing the jasmonate-based signaling pathway required for activation of host defense against Magnaporthe. Loss of ABM leads to increased production of methyl-jasmonate, which acts as a potent inducer of disease resistance in rice. The blast fungus secretes 12OH-JA into the host tissue and directly interferes with hormonal signaling involved in the pathogen recognition and defense system in rice. Interestingly, such regulation does not occur during Magnaporthe-barley interaction. Our data suggest a critical role for intrinsic jasmonates in Magnaporthe development, and a highly intricate chemical communication/signaling between Magnaporthe and Rice during the initiation of blast disease.

Abstract Number: C22-5, P8-232
Session Type: Concurrent