However, the specific genes affected by these mutations were not identified. The pathway in SBW25 has yet to be investigated. The identification of furanomycin as a secondary find more metabolite of P. fluorescens SBW25 adds to a small list of non-proteinogenic amino acids that

are known to be produced and secreted by pseudomonads. In addition to furanomycin, this list includes FVG, produced by WH6 [12], rhizobitoxine (4-(2-amino-3-hydroxypropoxy) vinylglycine), produced by P. andropogonis[33], methoxyvinylglycine (MVG, L-2-amino-4-methoxy-trans-3-butenoic acid), produced by P. aeruginosa (ATCC-7700) [34, 35], and 3-methylarginine, produced by P. syringae pv. syringae[36]. We have observed that a number of other strains of pseudomonads produce and secrete ninhydrin-reactive compounds that may represent non-proteinogenic this website amino acids, but these compounds have yet to be identified. The non-proteinogenic amino acids identified as secondary metabolites of pseudomonads all display some type of selective antimicrobial properties in in vitro tests. For example, FVG and MVG selectively inhibit the growth of Erwinia

amylovora, the causal agent of fireblight, an important disease of roseaceous orchard crops [25, 37]. MVG also inhibits growth of Acanthamoeba castellanii[38] and Bacillus sp. 1283B [35]. Likewise, 3-methylarginine suppresses the growth of P. syringae pv. glycinia, the causal agent of bacterial leaf blight [36]. Furanomycin click here has been shown previously to strongly inhibit T-even coliphage, as well as the growth of several microorganisms (Shigella paradysenteriae, Salmonella paratyphi A, and Bacillus subtilis) [26]. Our study expands the known range of bacteria that are susceptible to furanomycin

to include several plant pathogens, including D. dadantii, P. syringae, and E. amylovora, as well as the nonpathogenic strain Bacillus megaterium. The specificity of these effects is of particular interest in relation to the potential utility of these organisms for the biocontrol of plant pathogens. The production of furanomycin by SBW25 appears to account for the selective antibacterial activities of the culture filtrates from this organism grown under our culture conditions. The reversal of these effects in the presence of isoleucine is consistent with previous reports that this antibiotic functions as an isoleucine analog [26] and is recognized by the isoleucyl-tRNA synthetase from Escherichia coli, where it is charged to isoleucine-tRNA and interferes with protein synthesis in that organism [39]. It is less obvious why valine and leucine also interfere with the antibiotic activity of furanomycin, but it is possible that furanomycin interferes with the biosynthesis of branched-chain amino acids, and the presence of an exogenous source of isoleucine, leucine, or valine reverses or compensates for this interference.