Histone variant H2A.Z is a conserved regulator of RBOH expression and ROS production during innate immunity in Arabidopsis thaliana and Solanum lycopersicum.

Histone variant H2A.Z, a conserved variant of core histone H2A, has been widely accept as a master regulator of plant gene transcription and plant-environment interactions including pathogen resistance. Yet the exact roles of H2A.Z in mediating stepwise plant immune such as ROS production are not known, which is a pivotal step in plant-pathogen interactions and is predominantly controlled by the RESPIRATORY BURST OXIDASE HOMOLOGUE (RBOH) family. In this research, we found that mutation of three and two H2A.Z genes in Arabidopsis and tomato both reduced the plant pathogen-associated molecular patterns (PAMPs)-triggered ROS burst. Further study proved that AtRbohD and SlRbohB are constitutively upregulated in H2A.Z mutants, however the PAMP-induced activation of RBOHs are largely lost, which is accompanied with direct eviction of H2A.Z on AtRbohD. Besides, in tomato, mutation of H2A.Z resulted in compromised resistance to Pst. DC3000. To summarize, our results revealed a conserved role of H2A.Z in regulating PAMP-triggered RBOH activation, ROS production and immunity during pathogen invasion in Arabidopsis and tomato.