Comparative Analysis of Pathogenicity on Different Plant Parts of Acid Lime (Citrus aurantifolia) and Pathogenic Variability among Xanthomonas citri subsp. citri Isolates
Sushma A. Rao *
Department of Plant Pathology, VNMKV, Parbhani- 431402, Maharashtra, India.
K. T. Apet
Department of Plant Pathology, VNMKV, Parbhani- 431402, Maharashtra, India.
*Author to whom correspondence should be addressed.
Abstract
Citrus canker, caused by Xanthomonas citri subsp. citri, is one of the most destructive bacterial diseases affecting acid lime cultivation. The present study was undertaken to evaluate the pathogenicity of four isolates of Xanthomonas citri subsp. citri (Xac1, Xac2, Xac3 and Xac4) on different plant parts of acid lime (Citrus aurantifolia Swingle), namely leaves, stems, fruits and thorns, and to assess pathogenic variability among isolates using an attached leaf technique under screenhouse conditions. Inoculation induced typical citrus canker symptoms, characterised by water-soaked translucent spots, raised corky lesions and distinct yellow halos. Leaves were found to be the most susceptible plant part, exhibiting the shortest incubation period across all isolates. Among the four isolates tested, Xac2 proved to be the most virulent, producing the earliest symptoms (4 days on leaves) with the shortest average incubation period, while Xac4 was the least aggressive. Significant pathogenic variability was observed among the X. citri subsp. citri isolates, highlighting the importance of selecting virulent isolates for resistance screening and disease management strategies.
Keywords: Acid lime, Citrus canker, Xanthomonas citri subsp. citri, pathogenicity, pathogenic variability, virulence