A protein kinase coordinates cycles of autophagy and glutaminolysis in invasive hyphae of the fungus Magnaporthe oryzae within rice cells
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ABSTRACT: The devastating blast fungus Magnaporthe oryzae elaborates invasive hyphae (IH) in living rice cells during early infection, separated from host cytoplasm by plant-derived interfacial membranes, but the metabolic strategies underpinning this fundamental intracellular biotrophic growth phase are poorly understood. Eukaryotic cell growth depends on activated target-of-rapamycin (TOR) kinase signaling, which inhibits autophagy. Here, using live-cell imaging coupled with multiomic approaches, we show how the M. oryzae serine/threonine protein kinase Rim15 coordinates cycles of autophagy and glutaminolysis in IH – the latter through phosphorylation of NAD-dependent glutamate dehydrogenase – to reactivate TOR and promote biotrophic growth. Deleting RIM15 attenuated IH growth and triggered plant immunity; these defects were fully remediated by exogenous α-ketoglutarate treatment, but glucose treatment only suppressed host defenses. Our results together suggest that Rim15-dependent cycles of autophagic flux liberate α-ketoglutarate – via glutaminolysis – to reactivate TOR signaling and fuel biotrophic growth while conserving glucose for antioxidation-mediated host innate immunity suppression.
INSTRUMENT(S): Orbitrap Eclipse
ORGANISM(S): Magnaporthe Sp. Mg08
TISSUE(S): Mycelial Felt, Liver
SUBMITTER: Gang Li
LAB HEAD: Richard A. Wilson
PROVIDER: PXD043076 | Pride | 2023-07-10
REPOSITORIES: Pride
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