APS Abstracts of Presentations

Planktonic and biofilm growth of Xylella fastidiosa in chemically-defined media
Presenter: B. Leite, Florida A&M University, Tallahassee, FL
Co-Author(s): L. Marques, MBEC Bioproducts, Inc., Calgary, AB, Canada; P. Andersen, University of Florida, Quincy, FL; M. Olson, MBEC Bioproducts, Inc., Calgary, AB, Canada
Phytopathology 95:963

Xylella fastidiosa (XF) causes Pierce's disease in grapes and various diseases in other hosts. XF is injected into xylem vessels by xylem-feeding leafhoppers. XF can be planktonic or can form aggregates or biofilm. We compared growth and biofilm formation of UCLA and STL PD strains in three chemically-defined media, XF-26 (22 components), CHARD2 (10 components) and 3G10R (9 components). PW(^+), a rich non-defined medium, was used as control. During the incubation period of 9 days, both planktonic growth and biofilm formation were assessed at 2, 4, 7 and 9 days later. CHARD2 was by far the best medium inducing biofilm formation. CHARD2 and XF-26 differed in measurable planktonic growth; CHARD2 exhibited no planktonic growth, whereas XF-26 cultures were predominantly planktonic. These two media contain distinct levels of reducing agents. We hypothesize that the redox environment, in each medium, plays a significant role in determining biofilm formation and PD susceptibility.

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