|Stipanovic, Robert - Bob|
|Bell, Alois - Al|
|NICHOLS, ROBERT - Cotton, Inc|
Submitted to: Journal of Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/20/2015
Publication Date: 2/12/2015
Citation: Crutcher, F.K., Liu, J., Puckhaber, L.S., Stipanovic, R.D., Bell, A.A., Nichols, R.L. 2015. FUBT, a putative MFS transporter, promotes secretion of fusaric acid in the cotton pathogen Fusarium oxysporum f. sp. vasinfectum. Journal of Microbiology. 161(Pt4):875-883.
Interpretive Summary: Fusaric acid (FA) is a nonspecific toxin produced by the fungus responsible for Fusarium wilt of cotton and is involved in wilting symptoms and decreased yield in California cotton fields. A transporter involved in the export of FA out of the fungus into the soil/plant was identified. The transporter was involved in self-resistance of the fungus to FA. When the transporter was removed, the fungus did not produce FA and had decreased growth in the presence of FA. It was also discovered that when the transporter was eliminated, the fungus could break down FA so that it was less toxic. A better understanding of how FA is produced could lead to new methods of disease control, not just for cotton, but for other agricultural crops affected by similar types of wilt diseases.
Technical Abstract: Fusaric acid (FA) is a key component in virulence and symptom development in cotton during infection by Fusarium oxysporum. A putative MFS transporter gene was identified upstream of the polyketide synthase gene responsible for the biosynthesis of FA. Disruption of the transporter gene, designated FUBT, resulted in loss of FA secretion, decrease in FA production, and a decrease in resistance to high quantities of FA. Uptake of exogenous FA was unaffected in the disruption transformants, suggesting that FA enters the cell in Fusarium by an independent mechanism. Thus, FUBT is involved both in the extracellular transport of FA and in resistance of F. oxysporum to this non-specific toxin. A potential secondary resistance mechanism, the production of FA derivatives, was observed in FUBT deletion mutants. Molecular analysis of key biochemical processes in the production of FA may lead to future host-plant resistance to Fusarium pathogens.