SSR Genotype Analysis Of Phytophthora Infestans From Northeast And Hebei Province In China

Potato is one of the world’s four major crops, China is one of the world’s largest production bases of potato. Some fungal diseases have threated potato production, especially potato late blight caused by Phytophthora infestans, resulting in serious yield losses and even no harvest. In recent years, because P. infestans population genetic structure has changed, and potato late blight has aggravated the trend of popular, so strengthen the study on population genetic structure of P. infestans has important guiding significance on the prevention and treatment of potato late blight. P. infestans from Northeast and Hebei province in China were isolated and purified at first, and then the SSR genotypes of P. infestans from Northeast and Hebei province of China were analyzed based two microsatellites markers. The results were as follows.1. Ninety seven isolates of P. infestans were isolated and purified from 192 samples of potato late blight collected from 17 regions in Northeast and Hebei province of China in 2008, and the average separation of success rate was 51%.2. Some important parameters of the SSR reaction system aimed at genomic DNA of P. infestans were optimized. The optimal SSR-PCR reaction system which was suitable for our laboratory was as follows:the 25μL reaction system contained 2.5μL 10×PCR Buffer, each dNTP at 0.1 mmol/L,50ng DNA template,0.7U Taq DNA polymerase, primer at 0.5μmol/L, and 17.68μL ddH2O.3. With the two microsatellites Pi4B and Pi4G, a total of 6 SSR genotypes of P. infestans, which were B-01, F-01, F-04, F-05, F-06 and G-03, were identified among the 97 isolates. The genotype F-01 accounting for 72.1% was dominant genotype among them.4. Four SSR genotypes were identified in 59 strains from Hebei province, which were F-01, F-05, F-06 and G-03.52 out of them possessed genotype F-01, accounting for 88.1%. Genotype F-01 dominated the population of P. infestans population tested.4 SSR genotypes were found in 36 isolates from Heilongjiang province, which were F-01, F-04, F-06 and G-03. 17 out of 36 isolates accounting for 47.2% were F-01, and 14 out of them accounting for 38.9% were F-06. The one isolate of P. infestans from Jilin province belong to F-01, but one isolate of P. infestans from Liaoning province was B-01 genotype.5. Compared with the previously report of SSR geotypes, the results showed that the F-01 genotype was still dominant genotype in Hebei province and Heilongjiang province, but F-06 genotype has an upward trend in Heilongjiang province.