Botrytis cinereainduces local hypoxia in Arabidopsis leaves

Low oxygen availability often is associated with soil waterlogging or submergence, but may occur also as hypoxic niches in otherwise aerobic tissues. Experimental evidence assigns a role inBotrytis cinerearesistance to a group of oxygen-unstable Ethylene Response Factors (ERF-VII). Given that infection byB. cinereaoften occurs in aerobic organs such as leaves, where ERF-VII stability should be compromised, we explored the possibility of local leaf hypoxia at the site of infection. We analyzed the expression of hypoxia-responsive genes in infected leaves. Confocal microscopy was utilized to verify the localization of the ERF-VII protein RAP2.12. Oxygen concentration was measured to evaluate the availability of oxygen (O-2). We discovered that infection byB. cinereainduces increased respiration, leading to a drastic drop in the O(2)concentration in an otherwise fully aerobic leaf. The establishment of a local hypoxic area results in stabilization and nuclear relocalization of RAP2.12. The possible roles of defence elicitors, ABA and ethylene were evaluated. Local hypoxia at the site ofB. cinereainfection allows the stabilization of ERF-VII proteins. Hypoxia at the site of pathogen infection generates a nearly O-2-free environment that may affect the stability of other N-degron-regulated proteins as well as the metabolism of elicitors.

Automated summary

Infection by Botrytis cinerea induces local hypoxia in leaves, leading to stabilization of ERF-VII proteins. This hypoxic environment may impact the stability of other N-degron-regulated proteins and the metabolism of elicitors.