Variability of different isolates of xanthomonas axonopodis pv. citri causing citrus canker disease

Acid lime (Citrus aurantifolia) is grown different agro-climatic situation in West Bengal. The crop is commonly affected by citrus canker caused by Xanthomonas axonopdis pv. citri. There was variation in severity of the disease in different orchards. Xanthomonas axonopodis pv. citri isolated from five different orchard showed variation in respect to virulence and enzymatic activity. Isolates of the pathogen were XacJP from Jagannathpur, Paschim Medinipur, XacJ from Jaguli, Nadia, XacK from Kalyani, Nadia, XacMON from Mondouri, Nadia, XacMHP from Mohanpur, Nadia. Modouri isolate (XacMON) took minimum time (4 days) for expression of canker symptom on artificial inoculation and the lesion size was maximum. While maximum time (6 days) was taken for symptom expression by XacJP and lesion size was minimum. Others three isolates took 5 days for symptom expression. Highest cellulase activity was observed in XacMON followed by XacK, XacJ and XacMHP isolate. The lowest cellulase activity was observed in XacJP. Similarly highest pectinase and protease activity was recorded in Xac.MON. isolate. But the highest pectinase activity observed in XacMHP isolate. However, highest lipase activity was observed on Xac.JP.  XacMON isolate was found to be highly virulent and virulence had positive correlation with cellulase, pectinase and protease activity.