Variability in Xanthomonas oryzae pv. oryzae, the incitant of bacterial blight disease of rice. I. Physiological characterization of the isolates

摘要

Attempts were made to classify 52 isolates of Xanthomonas oryzae pv. oryzae, the causal organism of bacterial blight disease of rice, into different groups on the basis of their response to different physiological tests, utilization of carbohydrates and organic acids. The isolates could be classified into 12 groups on the basis of their response to carbohydrate utilization, 10 groups according to the organic acid utilization, 23 groups based on both carbohydrate plus organic acid utilization and 46physiotypes on the basis of all the 39 physiological tests. Grouping of the isolates following conventional method was also confirmed through clustering by numerical analysis, both the methods resulting in same number of groups with exactly similar constituent isolates in each group. The results demonstrated non-parallelism between clustering pattern and geographic distribution of the isolates or virulence pattern based on host-pathogen interaction or number of v-factors present in each pathogen isolate.