ISSR Marker and ITS Sequence Study of Melampsora Larici-populina

To compare the differences in intertranslation space of ribosomal DNA (ITS) of Melampsora larici-populina, between the isolates from China and isolates from other countries, this study investigated ITS sequences and ITS polygenetic tree based on 11 isolates that were collected from 5 races in different parts of China. The results indicated that there was no difference among the ITS sequences of 11 isolates from China. The ITS sequence of isolates from China was more homogeneous with that of isolates from Britain compared with France, Germany, and Canada. Intersimple sequence repeat (ISSR) markers were also used to study the genetic division of Melampsora larici-populina, and the results showed that the 11 tested isolates could be divided into Western population and Northern population. Genetic diversity index of race C2 was significantly different from that of races C4, C3, and C1, and no significant differences were observed among the other races. Pathogenicity division of races must not harmonize with their genetic division, except race C2. The ITS region is conservative, and ITS sequence is not fit for studying the differences that existed among the races. ISSR marker can be used for intraspecies population study, and Melampsora larici-populina in China can be divided into two populations.