ARS | Publication request: ACCUMULATION OF THE ANTIBIOTIC PHENAZINE-1-CARBOXYLIC ACID IN THE RHIZOSPHERE OF DRYLAND WHEAT

Submitted to: Microbial Ecology International Symposium
Publication Type: Abstract Only
Publication Acceptance Date: June 20, 2010
Publication Date: August 20, 2010
Citation: Mavrodi, D., Mavrodi, O., Bonsall, R., Kwak, Y., Parejko, Paulitz, T.C., Thomashow, L.S., Weller, D.M. ACCUMULATION OF THE ANTIBIOTIC PHENAZINE-1-CARBOXYLIC ACID IN THE RHIZOSPHERE OF DRYLAND WHEAT. Microbial Ecology International Symposium, 22-27 August, 2010, Seattle, WA.

Technical Abstract: Natural antibiotics are thought to function in microbial defense, fitness, competitiveness, biocontrol, communication and gene regulation activity, and antibiotic-producing species are commonly found in microbial communities throughout nature. However, the frequency and amount of antibiotic production in situ are poorly understood. We addressed this issue by measuring the geographic distribution of indigenous phenazine-producing (Phz+) Pseudomonas spp. and the amounts of phenazine-1-carboxylic acid (PCA) in the rhizosphere of wheat grown in the low-precipitation zone (<400 mm) of the Columbia Plateau in the Inland Pacific Northwest, USA. In 2008-2009 we conducted a survey of commercial dryland fields situated within an area of about three million acres that is roughly bounded by 46.8º and 47.9º N and 117.5º to 119º W. Phz+ Pseudomonas spp. were detected in all sampled fields with mean population sizes ranging from log 3.2 to log 7.1 g-1 fresh weight of root. PCA was detected in the rhizospheres of plants from 20 of 21 fields sampled. Linear regression analysis demonstrated a significant (P <0.0001) relationship between the population level of Phz+ isolates and the amount of PCA recovered from the plant rhizosphere.