|KUMAR, SONIKA - Washington State University|
|TRIPATHI, DIWAKER - Washington State University|
|TANAKA, KIWARMU - Washington State University|
Submitted to: Frontiers in Plant Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/9/2020
Publication Date: 9/18/2020
Citation: Kumar, S., Tripathi, D., Okubara, P.A., Tanaka, K. 2020. Purinoceptor P2K1/DORN1 enhances plant resistance against a soilborne fungal pathogen, Rhizoctonia solani. Frontiers in Plant Science. 11. https://doi.org/10.3389/fpls.2020.572920.
Interpretive Summary: Some soilborne fungal pathogens of wheat and barley have been difficult to manage using genetic resistance, biological control and commerical management resources, such as fungicides. This study takes a molecular approach to better understand a root pathogen for which little is known at the molecular level. The findings show that plant cellular wounding or damage, caused by some pathogens, releases molecules that can be perceived by the plant, and can trigger host defenses. Absence of certain proteins in this defense pathway render the plant more susceptible to the pathogens.
Technical Abstract: The purinoceptor P2K1/DORN1 recognizes extracellular ATP, a damage-associated molecular pattern (DAMP) released upon cellular disruption by wounding and necrosis, which in turn, boosts plant innate immunity. P2K1 is known to confer plant resistance to foliar fungal biotrophic and hemi-biotrophic pathogens, and the necrotrophic pathogen, Botrytis cinerea. However, until now, no information was available on its activity against root necrotrophic pathogens. In this report, we describe the contribution of P2K1 to resistance in Arabidopsis against Rhizoctonia solani AG-8, a broad host range, necrotrophic soilborne fungal pathogen. In pot assays, the Arabidopsis P2K1 knockout mutant dorn1-3 and the double mutant rbohd/f, defective in two subunits of the respiratory burst complex NADPH oxidase, exhibited significant reduction in shoot length, root length and rosette surface area in the presence of the pathogen, compared to wildtype Columbia Col-0. In contrast, the overexpression line OxP2K1 showed longer shoot and root lengths and a greater rosette surface area than the knock-out mutants or wildtype Col-0. Root expression of PR-1, PDF1.2 and JAZ5 was reduced in dorn1-3 and rbohd/f and elevated in OxP2K1 relative to wildtype, indicating that the salicylic acid and jasmonate defense signaling pathways functioned in resistance. These results indicated that a DAMP-mediated defense system confers basal resistance against an important root necrotrophic fungal pathogen.