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ARS Home » Plains Area » College Station, Texas » Southern Plains Agricultural Research Center » Insect Control and Cotton Disease Research » Research » Publications at this Location » Publication #357854

Research Project: Molecular and Genetic Approaches to Manage Cotton Diseases

Location: Insect Control and Cotton Disease Research

Title: Screening microbial resistance to fusaric acid, an antibiotic and phytotoxin produced by Fusarium wilt pathogens

Author
item Crutcher, Frankie - Montana State University
item Puckhaber, Lorraine
item Stipanovic, Robert - Retired ARS Employee
item Bell, Alois - Al
item Nichols, Robert - Cotton, Inc
item Lawrence, K - Auburn State University
item Liu, Jinggao

Submitted to: National Cotton Council Beltwide Cotton Conference
Publication Type: Abstract Only
Publication Acceptance Date: 11/16/2017
Publication Date: 5/20/2018
Citation: Crutcher, F.K., Puckhaber, L.S., Stipanovic, R.D., Bell, A.A., Nichols, R.L., Lawrence, K.S., Liu, J. 2018. Screening microbial resistance to fusaric acid, an antibiotic and phytotoxin produced by Fusarium wilt pathogens [abstract]. Proceedings of the National Cotton Council Beltwide Cotton Conferences, January 3-5, 2018, San Antonio, Texas. pg. 178.

Interpretive Summary:

Technical Abstract: Fusaric acid (FA), produced by fungal pathogen Fusarium oxysporum f. sp. vasinfectum (FOV), is likely a key intermediate in development of Fusarium Wilt of cotton (Gossypium spp.) and may also function as a defense against other soil microbes. Several microbes we tested appear to have evolved unique detoxification mechanisms of FA. We screened bacteria and fungi from soils infested with FOV and from laboratory sources to evaluate their ability to grow in the presence of FA and to alter the structure of FA into less toxic compounds. Bacterial strains failed to chemically modify FA. However certain Gram-negative bacteria, mainly in the genus of Pseudomonas, were found to be highly resistant. The FA resistance was positively correlated with the number of genes predicted to be FA efflux pumps in the genome of the bacteria. Phylogenetic analysis revealed that fusaric acid resistant protein family (FUSC) efflux pump proteins having high sequence identities with the functionally characterized FA resistance proteins FusC or Fdt might be the major contributors of FA resistance. Most fungi, on the other hand, converted FA to less toxic compounds regardless of the level of FA resistance they exhibited. Five conversion products were detected. The detoxification of FA involved either oxidation of the butyl side chain or reduction of the carboxylic acid group. Production of structurally related derivatives from widely different phyla indicates that resistance to FA by altering its structure is highly conserved. A few FA resistant saprophytic or potential biocontrol strains of fungi failed to alter FA, which suggested possible involvement of efflux transporters. FOV also utilized major facilitator superfamily transporter to pump out FA. Deployment of efflux and/or derivatization mechanisms may be a common feature of fungal FA resistance.