Identification Of Race Of Xanthomonas Campestris Pv. Campestris And Analysis Of Its Dominant Races In China

Black rot in cruciferous vegetables, caused by Xanthomonas campestris pv.campestris is a global disease, generally occurs, resulting in cruciferous vegetables a serious decline in quality and yield. Six races of X.campestris pv.campestris were reported in foreign country, but there is no report in China at present.The aim of this work was to identification the Race of X.campestris pv.campestris by AFLP fingerprinting and race typing on a set of differential Brassica spp.genotypes with the aim to suggest efficient control strategies involving breeding, introduction, and cultivation of resistant cultivars. The main results as follows:1. Collection of back-rot-infected leaf material , receive 311 isolations of X.campestris pv.campestris (use representative 61 isolations as follow study) , identification is X.campestris pv.campestris by pathogenicity testing, biological characteristics, BIOLOG automated microbial system identification and sequence analysis of 16S rDNA .2. 11 strains of X. campestris pv.campestris were defined on the basis of their reactions on a different set. Based on the strain in the host plant resistance response consistency division results: 1 Race has BJ3 , BJ19, K1, SX1 and HZ11, 4 Race has BJ4, HY2, HZ6, ZH3 and HN1; based on class average similarity cluster analysis divided the results: 1 Race has BJ3, BJ19, SX1, HZ11 and HN1; 4 Race has BJ4, HY2, HZ6, ZH3 and HK4.3. By six races and 16 pairs of AFLP primers, selected four pairs of polymorphic fragments: E113/M113, E112/M112, E13/M13 and E11/M11. The number of bands polymorphic polymorphic ratio: 208 (34.13%), 226 (14.16%), 234 (17.09%), 216 (14.81%).4. Primer E113/M113 will be distinguish physiological races at the molecular level. AFLP method and use differential host the two methods in the study of pathogenic differentiation is consistent with 81.8% .5. Using AFLP primer E113/M113 identify the race of 61 strains of X. campestris pv.campestris, the results is: 54.1% strains were identified as race1,36.1% strains as race 4, 6.6% strains as race 3;Race2,race5 and race6 were not found.North China Race 1 and Race 4, the proportion is similar to the South to the main Race 1. Cruciferae southwestern coastal areas and black rot is mainly on the Race1.