Submitted to: American Chemical Society National Meeting
Publication Type: Abstract Only
Publication Acceptance Date: July 6, 2010
Publication Date: July 12, 2010
Citation: Stipanovic, R.D., Puckhaber, L.S., Wheeler, M.H., Liu, J., Bell, A.A. 2010. Using carbon-13 to establish the biosynthesis of the plant toxin fusaric acid [abstract]. Proceedings of American Chemical Society National Meeting, March 21-25, 2010, San Francisco, California. 2010 CDROM. Technical Abstract: The plant pathogen Fusarium oxysporum f. sp. vasinfectum (F.o.v.) attacks cotton, alfalfa and okra. The recent discovery of new pathotypes (race 4) not previously found in the U.S. is of particular concern to the cotton industry, as is the inadvertent introduction of a unique and particularly virulent F.o.v. biotype from Australia. These F.o.v. isolates both produce prodigious quantities of fusaric acid, which differentiates them from most of the less virulent races previously recognized in the U.S. To combat this threat to U.S. cotton production, we conducted a systematic investigation to unequivocally determine fusaric acid biosynthesis and use gene knockout to demonstrate the role of fusaric acid in the pathogenicity of these isolates. We also conducted a series of 13C-labeled feeding studies that show fusaric acid is biosynthesized via a mixed polyketide synthase and a nonribosomal peptide synthase. Knockout of the polyketide synthase gene significantly reduced pathogenicity.