Study on the Genetic Variation of Physalospore piricola in Appleby Using RAPD Technique

In order to clarify the phenomenon of genetic variation in 4 different disease symptoms of apple disease, caused by Physalospore piriola, at molecular level, and the degree of genetic variation in 4 isolates of pathogenetic bacteria, the DNA fingerprint analysis of 26 related bacterial isolates ofPh. piricola from three major productive regions of apple in China was made by using RAPD technique. The results indicated that (1) Obvious genetic differences at the level of genomic DNA were found in different pathogenic bacterial isolate, and fingerprint of 4 of 11 polymorphic primers of amplification could distinguish the above mentioned 4 bacterial isolates from each other, among which the genetic distance was revealed by 0.1314~0.2541 on the basis of calculation of analytic data; (2) High genetic similarity (88.4~100%) between the identical symptom types from different sources of pathogenic bacteria were shown. It thus indicates the insignificant relation between the genetic differentiation and geographic difference. Above results of research are of importance in theoretic demonstration about the heredity and evolution of the disease Ph. piricola in apple fruit as well as in practice in improvement of identification and control technique for the disease.