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Exploring Antagonistic Metabolites of Established Biocontrol Agent of Marine Origin

Rane, Makarand Ramesh, Chaudhari, Bhushan Liladhar, Chincholkar, Sudhir Bhaskarrao
Applied biochemistry and biotechnology 2008 v.151 no.2-3 pp. 665-675
biological control agents, Pseudomonas aeruginosa, aquatic organisms, antifungal properties, metabolites, iron, siderophores, salicylic acid, plant pathogenic fungi, hydrogen cyanide, root diseases, indole acetic acid
Biocontrol ability of Pseudomonas aeruginosa ID 4365, a biocontrol agent of groundnut phytopathogens from marine origin, was previously attributed to the production of pyoverdin type of siderophores. However, pyoverdin-rich supernatants of this organism showed better antifungal activity compared to equivalent amount of purified pyoverdin indicating presence of undetected metabolite(s) in pyoverdin rich supernatants. On the basis of observation that antagonistic activity was iron-dependent and iron-independent, an attempt was made to detect the presence of additional metabolites. In addition to pyoverdin, strain produced additional siderophores, viz. pyochelin and salicylic acid. Two broad spectrum antifungal compounds, viz. pyocyanin and phenazine-1-carboxylic acid, were detected, characterized, and activity against phytopathogens was demonstrated. Iron- and phosphate-dependent co-production of siderophores and phenazines was confirmed. Strain showed additional features like production of hydrogen cyanide, indol-3-acetic acid, and phosphate solubilization.