A novel Zn chelate (TSOL) that moves systemically in citrus plants inhibits growth and biofilm formation of bacterial pathogens

Hajeewaka C Mendis; Ali Ozcan; Swadeshmukul Santra; Leonardo De La Fuente

doi:10.1371/journal.pone.0218900

A novel Zn chelate (TSOL) that moves systemically in citrus plants inhibits growth and biofilm formation of bacterial pathogens

PLoS One. 2019 Jun 24;14(6):e0218900. doi: 10.1371/journal.pone.0218900. eCollection 2019.

Authors

Hajeewaka C Mendis^{1

2}, Ali Ozcan^{2

3}, Swadeshmukul Santra^{2

3

4

5}, Leonardo De La Fuente¹

Affiliations

¹ Department of Entomology and Plant Pathology, Auburn University, Auburn, AL, United States of America.
² NanoScience Technology Center, University of Central Florida, Orlando, FL, United States of America.
³ Department of Chemistry, University of Central Florida, Orlando, FL, United States of America.
⁴ Department of Materials Science and Engineering, University of Central Florida, Orlando, FL, United States of America.
⁵ Burnett School of Biomedical Sciences, University of Central Florida, Orlando, FL, United States of America.

Abstract

Ternary solution (TSOL) is a novel Zn chelate-based systemic antimicrobial formulation designed for treating citrus bacterial pathogens 'Candidatus Liberibacter asiaticus' and Xanthomonas citri subsp. citri. TSOL is a component of MS3T, a novel multifunctional surface/sub-surface/systemic therapeutic formulation. Antimicrobial activity of TSOL was compared with the antimicrobial compound ZnO against X. citri subsp. citri and 'Ca. L. asiaticus' surrogate Liberibacter crescens in batch cultures. X. citri subsp. citri and L. crescens were also introduced into microfluidic chambers, and the inhibitory action of TSOL against biofilm formation was evaluated. The minimum inhibitory concentration of TSOL for both X. citri subsp. citri and L. crescens was 40ppm. TSOL was bactericidal to X. citri subsp. citri and L. crescens above 150 ppm and 200 ppm, respectively. On the contrary, ZnO was more effective as a bactericidal agent against L. crescens than X. citri subsp. citri. TSOL was more effective in controlling growth and biofilm formation of X. citri subsp. citri in batch cultures compared to ZnO. Time-lapse video imaging microscopy showed that biofilm formation of X. citri subsp. citri was inhibited in microfluidic chambers treated with 60 ppm TSOL. TSOL also inhibited further growth of already formed X. citri subsp. citri and L. crescens biofilms in microfluidic chambers. Leaf spraying of TSOL showed higher plant uptake and systemic movement in citrus (Citrus reshni) plants compared to that of ZnO, suggesting that TSOL is a promising antimicrobial compound to control vascular plant pathogens such as 'Ca. L. asiaticus'.

Publication types

Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

Anti-Bacterial Agents / pharmacology*
Biofilms / drug effects*
Citrus / microbiology*
Liberibacter
Microbial Sensitivity Tests / methods
Plant Diseases / microbiology
Plant Leaves / microbiology
Rhizobiaceae / drug effects*
Xanthomonas / drug effects*
Zinc / metabolism*

Substances

Anti-Bacterial Agents
Zinc

Supplementary concepts

Liberibacter crescens

Grants and funding

This project was funded by Agriculture and Food Research Initiative competitive grant no. 2016-70016-24828 from the USDA National Institute of Food and Agriculture Specialty Crops Research Initiative (NIFA-SCRI) awarded to SS and LD; Citrus Research and Development Foundation grant (Project No. 15-037C); and the HATCH AAES (Alabama Agricultural Experiment Station) program awarded to LD. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.