title: Isolation and in vitro and in vivo activity against Phytophthora capsici and Colletotrichum orbiculare of phenazine-1-carboxylic acid from Pseudomonas aeruginosa strain GC-B26.
abstract: The bacterial strain GC-B26, which showed strong antifungal and anti-oomycete activity against some plant pathogens, was isolated from a grassland soil in Korea. Based on morphological, physiological and biochemical characteristics, GC-B26 was identical to Pseudomonas aeruginosa (Schroeter) Migula. The antibiotic G26A, active against Phytophthora capsici Leonian and Colletotrichum orbiculare (Berk & Mont) van Arx, was isolated from the culture filtrates of Ps aeruginosa strain GC-B26 using various chromatographic procedures. The EI mass and UV spectral results indicated that G26A is an analogue of phenazines, having molecular formula C13H8N2O2 (M+, m/z 224.0664). On the basis of NMR spectral data, G26A was confirmed as phenazine-1-carboxylic acid. C orbiculare, P capsici and Pythium ultimum Trow were most sensitive to G26A, with MIC values of approximately 5 microg ml(-1). However, no antimicrobial activity was found against yeasts and bacteria, even at a concentration of over 100 microg ml(-1). Treatment with the antibiotic gave highly significant protective activity against the development of Phytophthora disease on pepper and anthracnose on cucumber plants. The disease control efficacy was only slightly less than that of the commercial fungicides metalaxyl and chlorothalonil.
authors.affiliation: Laboratory of Molecular Plant Pathology, College of Life and Environmental Sciences, Korea University, Seoul 136-701, Korea.
authors.forename: Jung Yeop
authors.initials: JY
authors.lastname: Lee
authors.forename: Surk Sik
authors.initials: SS
authors.lastname: Moon
authors.forename: Byung Kook
authors.initials: BK
authors.lastname: Hwang
mesh_terms: D000935:Antifungal Agents / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D002212:Capsicum / Q000382:microbiology; D020231:Colletotrichum / Q000187:drug effects*; D018553:Cucumis sativus / Q000382:microbiology; D008826:Microbial Sensitivity Tests; D015394:Molecular Structure; D010619:Phenazines / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D010838:Phytophthora / Q000187:drug effects*; D010935:Plant Diseases / Q000382:microbiology; D011550:Pseudomonas aeruginosa / Q000737:chemistry*
chemical_list: D000935:Antifungal Agents; D010619:Phenazines; C037165:1-phenazinecarboxylic acid