Study Of Genetic Population Structure Of Puccinia Striiformis F.SP. Tritici Originated From Shaanxi, Gansu And Sichuan Provinces In China

Stripe rust (or yellow rust) of wheat (Triticum aestivum), caused by Puccinia striiformis f. sp. tritici, is one of the most important diseases of wheat in China. The fungus is an obligate biotrophic pathogen. Spores of it could be spread by wind in long distance, so making epidemics across large areas. Since Longnan and northwest of Sichuan is one of the most important over-summering areas of P. striiformis f. sp. tritici in China, the objective of this study was to determine genetic structure of P. striiformis f. sp. tritici populations in this region with TP-M13-SSR technique. The main results are summarized as following:1. Genetic diversity for the pathogen population from northwest of Sichuan and Sichuan Basin were much higher than that from other regions. Genetic differentiation was also investigated. The results showed that interregional genetic variation accounted for 14.92% of the total, while interpopulational variation 23.6% and intrapopulational variation 60.02%. Moreover, our molecular data on gene flow and genotype confirmed the migration of pathogen populations among regions in Sichuan, in particular, between northwest of Sichuan and Sichuan Basin.2. Stripe rust of wheat population in Shaanxi Province had a high genetic diversity, no difference between the different regions. Stripe rust populations had low genetic variability, genetic variation between regions accounted for 12.26%, while interpopulational variation 10.88%, 76.86% within populations, genetic variation exists within groups. Gene flow confirmed there is widespread throughout the range of exchange or short-distance movement in Shaanxi Province. Southern of Shaanxi and Guanzhong groups had significant gene flow.3. Genetic diversity of the population from Longnan and Tianshui were higher than that from Pingliang region. Genetic differentiation of it was so lower. The results showed that Gst is 0.17, intrapopulation variation 83%. Our molecular data on gene flow confirmed the migration of pathogen populations among regions in Gansu Province. In particularly, gene flow is stronger between Tianshui and Pingliang than other regions.4. Genetic diversity of the population from Longnan population, Tianshui population and Sichuan Basin population is higher than others'population in Shaanxi Province, Gansu Province and Sichuan Province. Result showed that SSR genetype of the stipe rust from three provinces was rich.