|Kristina, Rogers - UNIV OF IOWA CHEMISTRY|
|Gloer, James - UNIV OF IOWA CHEMISTRY|
Submitted to: American Phytopathological Society Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: July 28, 2007
Publication Date: July 28, 2007
Citation: Poling, S.M., Wicklow, D.T., Kristina, R., Gloer, J. 2007. Acremonium zeae, a protective endophyte of maize, produces dihydroresorcylide and 7-hydroxydihydroresorcylides [abstract]. American Phytopathological Society Annual Meeting. Technical Abstract: Acremonium zeae has been characterized as a protective endophyte of maize and shows antifungal activity against other fungi. Pyrrocidines A and B were found to be the metabolites accounting for this activity in a number of different A. zeae isolates. Pyrrocidine A displays potent activity against major stalk and ear rot pathogens of maize. In order to evaluate the generality of this observation, 154 A. zeae isolates obtained from maize seeds produced in nine states were surveyed for the ability to produce pyrrocidines. In the course of this work, another metabolite of A. zeae, unrelated to the pyrrocidines, was found to have widespread occurrence (105 of 154 isolates). In many cases, this compound was found to be produced in amounts comparable to the pyrrocidines. Detailed chemical studies of fermentation extracts of one of these A. zeae isolates (NRRL 45893) led to the identification of this metabolite as dihydroresorcylide, a reduced analog of the known compound cis-resorcylide. Two diastereomeric 7-hydroxydihydroresorcylides were also encountered. Dihydroresorcylide and pyrrocidines A and B were detected by LC-APCI-MS in symptomatic kernels removed at harvest from ears of a commercial maize hybrid that were wound-inoculated in the milk stage with A. zeae NRRL 34559. Dihydroresorcylide caused necrosis on maize using the leaf-puncture wound assay (5 ug/needle wound, but was inactive (MIC >50 ug/mL) against common fungal pathogens of maize.