Skip to main content
ARS Home » Midwest Area » Columbia, Missouri » Plant Genetics Research » Research » Publications at this Location » Publication #141061
Title: FUNGAL RESPONSIVE FATTY ACID ACETYLENASES OCCUR WIDELY IN EVOLUTIONARILY DISTANT PLANT FAMILIES

Author
item Cahoon, Edgar
item SCHNURR, JUDY - DUPONT CROP GENETICS
item HUFFMAN, ERROL - MIAMI UNIV., OXFORD, OH
item MINTO, ROBERT - MIAMI UNIV., OXFORD, OH

Submitted to: Plant Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/27/2003
Publication Date: 6/1/2003
Citation: CAHOON, E.B., SCHNURR, J.A., HUFFMAN, E.A., MINTO, R.E. FUNGAL RESPONSIVE FATTY ACID ACETYLENASES OCCUR WIDELY IN EVOLUTIONARILY DISTANT PLANT FAMILIES. PLANT JOURNAL. 2003. v. 34. p. 671-683.

Interpretive Summary: Crop loss due to pathogenic fungi, insects, and nematodes is a persistent drain upon the productivity and economic viability of U.S. agriculture. In this study, the function was established for genes that are responsive to fungal pathogenesis in a variety of plants including sunflower. The enzyme corresponding to this gene was shown to produce an unusual fatty acid product that is the precursor of molecules that have demonstrated fungicidal, insecticidal, and nematicidal activity. This study lays the groundwork for future efforts by plant scientists to engineer increased pathogen resistance in economically important crop plants and lessen the U.S. farmers' reliance on chemical pesticides.

Technical Abstract: The fungal elicitor-induced ELI12 gene from parsley has been previously shown to encode a divergent form of the delta12-oleic acid desaturase. In this report, we show that the ELI12 gene product is a fatty acid acetylenase or triple bond-forming enzyme. Expression of this enzyme in transgenic soybean seeds was accompanied by the accumulation of the delta12-acetylenic fatty acids crepenynic and dehydrocrepenynic acids. Using PCR with degenerate oligonucleotides, we also show that homologs of the ELI12 gene are present in other members of the Apiaceae family. In addition, cDNAs for divergent forms of the delta12-oleic acid desaturase were detected among ESTs from English ivy, an Araliaceae species, and sunflower, an Asteraceae species. As with the ELI12 gene, expression of these cDNAs in transgenic soybean embryos was accompanied by the accumulation of crepenynic and dehydrocrepenynic acids. Homologs of the sunflower acetylenase gene were also detected in other Asteraceae species, as revealed by PCR analysis of isolated genomic DNA. Results from Northern and EST analyses indicated that expression of the sunflower gene, like ELI12, is induced by fungal elicitation. Overall, these results demonstrate that expressed genes for delta12-fatty acid acetylenases occur in at least three plant families and are responsive to fungal pathogenesis. Natural products derived from crepenynic and dehydrocrepenynic acids that display antifungal, insecticidal, and nematicidal properties are distributed through at least 15 plant families, including Apiaceae, Asteraceae, and Araliaceae species. The acetylenases described here thus provide probes for chemotaxonomists and facilitate functional genomic and molecular investigations of these defensive mechanisms.