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Poster: Biology & Disease Mgmt: Chemical Control


Evaluation of a novel antimicrobial compound to control growth and biofilm formation in vitro of citrus bacterial pathogens
H. MENDIS (1), E. Naranjo (1), S. Santra (2), M. Young (2), E. Johnson (3), P. Rajasekaran (2), L. De La Fuente (1) (1) Auburn University, U.S.A.; (2) University of Central Florida, U.S.A.; (3) Citrus Research and Education Center, University of Florida,

ZinkicideTM is a novel plant nutrient-based antimicrobial formulation developed for treating citrus bacterial pathogens including ‘Candidatus Liberibacter asiaticus’ (Las) and Xanthomonas citri subsp. citri (Xac). As per the design, ZinkicideTM is expected to enter phloem tissues of citrus plants when sprayed onto leaves for control of phloem-limited pathogens such as Las. This study investigated the effects of ZinkicideTM in vitro on growth and biofilm formation of Las surrogate Liberibacter crescens and Xac in batch cultures and under flow conditions using microfluidic chambers. Xac was grown in 96-well plates in Nutrient Broth and treated with serial dilutions of ZinkicideTM to test inhibition of growth and biofilm formation. Xac was also introduced to microfluidic chambers under constant media flow, and inhibitory action of ZinkicideTM on biofilm formation was recorded using time-lapse video imaging microscopy. The ZinkicideTM formulation had better antimicrobial properties compared to similar formulations with the same active ingredients, and the minimum inhibitory concentration of ZinkicideTM for Xac was calculated at 10ppm. Time-lapse video imaging showed that untreated Xac grown in microfluidic chambers formed biofilm whereas Xac treated with ZinkicideTM did not form any biofilm. In vitro results confirmed that ZinkicideTM is effective against citrus bacterial pathogens and inhibits bacterial growth and biofilm formation under flow conditions.