Plant Science Research, Vol. 45, 2023

Cell death in Arabidopsis mediated by AtATG6 provides immunity against Magnaporthe oryzae

Rice succumbs to Magnaporthe oryzae, causing rice blast, while Arabidopsis, acting as a nonhost, deploys an active defense mechanism against the pathogen. Despite extensive gene and QTL identification, no cure for rice blast has been found. Arabidopsis employs nonhost resistance (NHR) with a hypersensitive response (HR) involving localized programmed cell death, crucial for pathogen limitation and resistance. Recognizing the pivotal link between cell death and disease resistance, our study delves into the relationship between AtATG6 and HR-associated cell death, focusing on its role in resisting Magnaporthe oryzae. In our experiments, both wild-type Col-0 and ATG6 mutant Arabidopsis were exposed to Magnaporthe oryzae, with trypan blue staining and electrolyte assays gauging cell viability dynamics. Microscopic representation of the oxidative burst examined the correlation between reactive oxygen species (ROS) generation and cell death. As revealed by the relative expression patterns of defense genes (PR1, WRKY53, and WRKY29), the mutant ATG6 operates by subverting the defense mechanism. Raman spectra analysis uncovered compromised plant immunity, manifesting as variations in carotenoid levels. This study illuminates the intricate interplay of AtATG6, cell death, and disease resistance in defense against Magnaporthe oryzae by Arabidopsis.