Magnaporthe oryzae MoPh1 perceives ER stress and promotes adaptive responses via a plasma membrane-to-vacuole pathway

During growth and development, cells experience both internal and external stresses, which can exert harmful impacts if they are poorly managed. Endoplasmic reticulum (ER) stress is an internal stress that is induced when protein misfolding or perturbations occur at excess rates, and the conventional response pathways from the ER to the nucleus are activated to address the stress. However, the involvement of the plasma membrane (PM) system in response to this internal stress has been insufficiently investigated. Here, a PM sensor, MoPh1, was observed to perceive stress through ER-PM contact sites and target the autophagosome and vacuole, consequently stimulating the autophagy process and supporting stress relief. The PM-to-vacuole pathway mediated by MoPh1 is independent of the classical ER-to-nucleus pathway and might be highly important in both fungi and plants, as it plays a crucial role in alleviating ER stress and promoting cellular adaptation for cell survival. The unfolded protein response is activated at the ER due to protein misfolding. Here the authors show that in Magnaporthe oryzae, the plasma membrane localized MoPh1 protein perceives stress through ER-PM contact sites and stimulates autophagy to support stress relief.