Regulation of the NADPH Oxidase RBOHD During Plant Immunity.
Pathogen recognition induces the production of reactive oxygen species (ROS) by NADPH oxidases in both plants and animals. ROS have direct antimicrobial properties, but also serve as signaling molecules to activate further immune outputs. However, ROS production has to be tightly controlled to avoid detrimental effects on host cells, but yet must be produced in the right amount, at the right place and at the right time upon pathogen perception. Plant NADPH oxidases belong to the respiratory burst oxidase homolog (RBOH) family, which contains 10 members in the model plant Arabidopsis thaliana. The perception of pathogen-associated molecular patterns (PAMPs) by pattern recognition receptors (PRRs) leads to a rapid, specific and strong production of ROS, which is dependent on RBOHD. RBOHD is mainly controlled by Ca(2+) via direct binding to EF-hand motifs and phosphorylation by Ca(2+)-dependent protein kinases. Recent studies have, however, revealed a critical role for a Ca(2+)-independent regulation of RBOHD. The plasma membrane-associated cytoplasmic kinase BIK1 (BOTRYTIS-INDUCED KINASE1), which is a direct substrate of the PRR complex, directly interacts with and phosphorylates RBOHD upon PAMP perception. Impairment of these phosphorylation events completely abolishes the function of RBOHD in immunity. These results suggest that RBOHD activity is tightly controlled by multilayered regulations. In this review, we summarize recent advances in our understanding of the regulatory mechanisms controlling RBOHD activation.
RIKEN Center for Sustainable Resource Science, Plant Immunity Research Group, Suehiro-cho 1-7-22 Tsurumi-ku, Yokohama, 230-0045 Japan yasuhiro.kadota@riken.jp.
Yasuhiro
Y
Kadota
RIKEN Center for Sustainable Resource Science, Plant Immunity Research Group, Suehiro-cho 1-7-22 Tsurumi-ku, Yokohama, 230-0045 Japan.
Ken
K
Shirasu
The Sainsbury Laboratory, Norwich Research Park, Norwich NR4 7UH, UK.
Cyril
C
Zipfel
D017360:Arabidopsis / Q000201:enzymology* / Q000235:genetics / Q000276:immunology; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000276:immunology / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D019255:NADPH Oxidases / Q000235:genetics* / Q000276:immunology / Q000378:metabolism; D000069452:Pathogen-Associated Molecular Pattern Molecules; D010766:Phosphorylation; D057865:Plant Immunity; D017382:Reactive Oxygen Species / Q000378:metabolism; D051192:Receptors, Pattern Recognition / Q000235:genetics / Q000378:metabolism
D029681:Arabidopsis Proteins; D000069452:Pathogen-Associated Molecular Pattern Molecules; D017382:Reactive Oxygen Species; D051192:Receptors, Pattern Recognition; C568857:AT5G47910 protein, Arabidopsis; D019255:NADPH Oxidases
Calcium; Innate immunity; Pathogen-associated molecular patterns; Pattern recognition receptors; Phosphorylation; Reactive oxygen species