Andras Fodor
University of Wisconsin-Madison, USA
Title: Comparative analysis, target specicities and plant protection potential of antimicrobial peptides isolated from xenorhabdus species
Biography
Biography: Andras Fodor
Abstract
Research conception: Xenorhabdus species entomopathogenic nematode-symbiotic bacteria are produce NRP antimicrobial peptides to protect the monoxenic nematode-bacterium symbiotic complex in soil condition. The HPLC and MALDI analysis show that the profiles of the different species are different. The target specificities of the different peptides overlap. Aim: We determined the target specificities of some HPLC fractions of the antimicrobial peptide-rich fractions (APRF) uniformly prepared from antibiotics-producing strains. Method: We prepared antibiotic peptide-rich fractions (APRF) from X. budapestensis HGB2238, X. marinarium HGB2199, X, szentimaii HGB2239, and X. nematophila ATTC61019. We compared the HPLC and MALDI profile and also the antimicrobial activities of the different fractions against Gram positive (S. aureus) and negative (E. coli, Agrobacterium tumefaciens, Erwinia amylovora; some other plant and pathogenic) bacteria; fungi (Candida albicans) and Oomycete (Phytophthora infestans). Results: APR fractions active against (i) only Gram positive bacteria; some are produced in mutants of secondary phenotypes as well. X. marianensis has an anti-Gram (+) activity which could not be bound to reverse phase column; (ii) bacteria, oomycete and fungal target. Bicornutin A does not have antimicrobial activity but play a role in the Xenorhabdus antimicrobial scenario. The plant protection potential of X. budapestensis is demonstrated by in vitro and in planta experiments on fire-blight infested apple flowers. Significance: The spreading multidrug resistance occurring in both prokaryotic and eukaryotic pathogens urge to find new compound of strong antimicrobial potential and of novel mechanisms of action The Xenorhabdus genus is a golden mine of such compounds.