Abstract:

Botryosphaeria Ces. et de Not., its a sexual phase is Dothiorella Sacc., causes canker of many varieties of trees and its distribution region is very wide. These two agents cause molecular gene diversity. PCR-amplified 28S rDNA products of 30 isolates from 5 regions and 14 varieties of host trees were the same. The polymorphism on digestion with six restriction enzymes was nearly the same. So, the 28S rDNA-PCR-RFLP analysis was not suitable for differentiating the species within genera. RAPD analysis of all the isolates showed that there was abundant polymorphic DNA within the genera(92.81%). All the tested isolates were divided into 13 clusters according to 0.845 similarity. One part of isolates manifested the differentiation because of different origin and host. The pathogen of Cedrus deodara canker was proved to be B.dothidea according to its DNA polymorphism. So, the host of the pathogen was very wide, including angiosperm and gymnosperm. Two primers of RAPD analysis, K16 and R14, could be the identification primers as differentiating the isolates of Shanxi province and Hunan province from others. RAPD analysis demonstrated that the traditional taxonomy of B.berengeriana de Not.f.sp.piricola (Nose)Koganezawa et Sakuma as the specialization of B.berengeriana de Not. Was reasonable. And these two pathogens causing apple canker were different species from that one causing Poplar canker.

Key words: Botryosphaeria, 28S rDNA-PCR-FLP, RAPD, Identifying primers