Submitted to: American Phytopathological Society
Publication Type: Abstract Only
Publication Acceptance Date: March 15, 2006
Publication Date: July 29, 2006
Citation: Wicklow, D.T., Poling, S.M. 2006. Antimicrobial activity of pyrrocidines from Acremonium zeae against endophytes and pathogens of maize [abstract]. American Phytopathological Society. Technical Abstract: Acremonium zeae is recognized as a protective endophyte of maize which augments host defenses against microbial pathogens causing seedling blights and stalk rots. A. zeae produces pyrrocidines A and B, polyketide-amino acid-derived antibiotics which have been shown to display significant in vitro activity (M.I.C.) against Aspergillus flavus and Fusarium verticillioides, with pyrrocidine A being more active than B. Pyrrocidine A revealed potent antibiotic activity against major stalk and ear rot pathogens of maize Fusarium graminearum, Stenocarpella (Diplodia) maydis, and kernel rotting fungal pathogens including Alternaria alternata, Cladosporium cladosporioides, Curvularia lunata, and Nigrospora oryzae. Mycoparasites living asymptomatically within healthy maize tissues showed little sensitivity to pyrrocidines. Pyrrocidines also exhibit potent antibiotic activity against Bacillus mojaviense, Pseudomonas fluorescens, bacterial endophytes applied as biocontrol agents, and Clavibacter michiganense subsp. Nebraskense, causal agent of Goss's bacterial wilt, yet were ineffective against the wilt producing bacterium, Pantoea stewartii. A. zeae grows systemically within maize and thus represents a potential confounding variable in variety trials for disease resistance.