Zinc-based nutritional antimicrobials as a dual-action strategy against Xanthomonas citri in Citrus limon

Description

Citrus canker, caused by Xanthomonas citri pv. citri, is a major constraint to citrus production worldwide, including the high-value cultivar Citrus limon (Kaji Nemu) in Assam, India. Conventional management depends largely on copper based bactericides and antibiotics, which raise concerns regarding environmental contamination and resistance develop ment. This study evaluated the comparative antibacterial efficacy of four zinc-based compounds—zinc oxide, zinc nitrate, zinc sulphate, and zinc EDTA as potential sustainable alternatives. In-vitro assessment using a micro broth dilution assay showed zinc oxide to be the most effective, with a minimum inhibitory concentration of 100 ppm, while zinc nitrate and zinc sulphate were effective at 700 ppm; zinc EDTA showed no inhibition up to 1000 ppm. In-planta evaluation under greenhouse conditions confirmed the superior performance of zinc oxide, which significantly reduced disease incidence, disease severity, and in-planta bacterial colonization. Zinc oxide achieved more than 70% reduction in disease severity and maintained the lowest X. citri pv. citri population. Two-way ANOVA and Tukey’s HSD tests revealed significant effects of treatment, time, and their interaction. The dual role of zinc oxide as a micronutrient and antimicrobial agent highlights its potential as an environmentally compatible component of sustainable citrus canker management, particularly in regions facing copper resistance and ecological concerns.

Institutions

• Nanda Nath Saikia College

  Assam, Titābar

Categories

Funders

• Science and Engineering Research Board

  Department of Science and Technology

  New Delhi

  Grant ID: SRG/2022/001969

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