Vegetos
(An International Journal of Plant Research & Biotechnology)
Zinc-based nutritional antimicrobials as a dual-action strategy against Xanthomonas citri in Citrus limon
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Research Articles | Published: 11 March, 2026
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Keywords: n Citrus limonn , Citrus canker, Zinc oxide, n Xanthomonas citrin , Antibacterial efficacy, In-planta assay
Abstract
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 development. 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.
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Author Information
Department of Plant Pathology, Assam Agricultural University, Jorhat, India