| Wheat stripe rust (Puccinia striiformis West. f.sp. tritici) is common and serious in China. The Chinese region is the biggest and unique epidemic region of wheat stripe rust in the world. Presently,the better methods against the wheat stripe rust are using resistance cultivars and chemicals. But whatever measures will be taken, the first step is to observe the virability of virulence and the structure of the populations of Puccinia striiformis West. f.sp. tritici in shortest time.The reason how new virulent isolates product is virlence variance. The fungi can variant through gene mutation and heterokaryosis, heterokaryosis had have some pilot study. But the reports about variation on level of molecule in Puccinia striiformis were not found.The study is to select new islate of wheat rust from the mixture of two original races with ten isolates and white isolate.And to find DNA polymorphisms in 17 races with SSR (microsatellite markers). The results as follows:1.Four new isolates has been obtained from the mixture of different races, reproducing on the same wheat cultivar simultaneously It found that the virulence of the new isolates was obviously different from that of original races .the SSR primer RJ17 was used to analyze the new isolate and other experimental isolates. We learned the new isolate that was producted by heterokaryosis.2. One about 170bp special polymorphism band of white race has been obtained when the SSR primer RJ3 was used to analyze the 17 experimental isolates.3. One about 300bp special polymorphism band of CY26 has been obtained, when the SSR primer RJ18 was used to analyze the 17 experimental isolates.4. One about 210bp special polymorphism band of CY29 has been obtained when the SSR primer RJ4 was used to analyze the 17 experimental isolates. Then the band was affirmed by repeat experiment.5. About 310bp special polymorphism band related virulence gene to Yr9 has been obtained, when the SSR primer RJ24 was used to analyze the 17 experimental isolates.The study obtained message about virulence viariation and races of Puccinia striiformis West. f.sp. tritici can offer consult and help for wheat rust study about variation and evolution. |
