DIVERSITY OF PATHOGENIC BACTERIA FROM RICE SEEDS

XIE Guan lin,ZHU Guo nian, REN Xiao ping (Plant Protection Department, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou 310029, China)

pathogenic bacteria of rice seed; identification of bacteria; isolation frequency; seedborne; seed transmission

A survey on diversity of pathogenic bacteria including frequency and transmission of the pathogens from plain, hill and mountain areas of Zhejiang Province was conducted during 1997-2000. More than 3 906 bacterial isolates were recovered from 303 rice seed samples. Two hundreds and one pathogenic bacteria accounting for 5.15% of the total isolates were obtained after colony morphology, bacteriology and pathogenicity test. Together with 23 standard reference strains 299 pathogenic and representative nonpathogenic isolates were confirmed by Biolog. Results showed that the seedborne bacteria belonged to 6 higher virulent and 5 low virulent species. The pathogenic species isolated from the samples of plain area were more than those from mountain area. However, the low virulent species were prevalence in the two areas. Isolation frequency of the higher virulent species from hill was significantly higher than those from other areas. Among 11 seedborne bacteria only Xanthomonas oryzae pv. oryzicola, Pseudomonas fuscovaginae and Acidovorax avenae subsp. avenae were confirmed as seedborne and seed transmission by using both artificial inoculated and naturally infected seeds.