Jeffrey H. Toney1, Mipha L. Koh1
1Montclair State University, Montclair, NJ
Tóm tắt
Xylella fastidiosa (Xf) is the causative agent of Pierce's disease in a variety of commercially important plants such as citrus, coffee, and grapes. By blocking the xylem, Xf disrupts water and nutrient transport. Xf is a gram-negative phytopathogen that can form biofilms. Twelve genes have been identified in Xf that can regulate exopolysaccharides, a major component of biofilms, including aconitase, which responds to intracellular iron levels. We have employed a quantitative assay for biofilm formation referred to as minimal biofilm elimination concentration (MBEC) assay that is amenable for highthroughput screening. Biofilm formation by Xf (Napa, CA) can be blocked using iron chelators such as lactoferrin (LF), ethylenediaminetetraacetic acid (EDTA), and S, S' ethylenediaminedisuccinic acid (EDDS). Incubation of Xf in the presence of LF at 1000 μg/mL for 3.5 days showed inhibition of biofilm formation (42%) as well as inhibition (32%) of planktonic growth (liquid-phase bacteria). EDTA at a concentration of 15 mg/mL inhibited 99.7% of biofilm formation and 98.9% of planktonic growth in a 24 h incubation. In contrast, EDDS at a concentration of 38.2 mg/mL showed 64.7% inhibition of biofilm formation and 33.6% inhibition of planktonic growth. Iron deprivation could serve as a first step toward eradication of Pierce's disease via blockage of biofilm formation.
