Evaluation Of Potato Germplasms Resistant To Bacterial Wilt And Screening Of Effector Mutants Of Ralstonia Solanacearum

Potato, the main crop used as food, vegetables, animal feed and raw materials for industry, plays an important role in industrial and agricultural production in China. However, potato is a kind of crops which is seriously infected by disease,especially by Phytophthora Infestans and Ralstonia solanacearum. Bacterial wilt(BW) caused by Ralstonia solanacearum(Rs) is one of the most devastating plant bacterial disease. But, there is no effect means to prevent bacterial wilt. We have not found effect resistant resource to Ralstonia solanacearum in potato cultivars. Luckily, there is a large amount of resistant resource in wild potato species. Resistant germplasm is the base o f genetic improvement.Therefore, the systematic investigation to the bacterial wilt tolerance of wild potato species will highly contribute to provide the foundation for potato breeding with bacterial wilt resistant trait. In this research, a direct identification method of seeding with Ralstonia solanacearum was carried out by 316 potato lines. We have evaluated the potato gerplasm resistant to bacterial wilt. In order to find the avirulence effector proteins,the resistant materials were inoculated by the mutants of effector protein of Ralstonia solanacearum.The main results are as follows:1. Phenotypic evaluation of 316 potato lines. A total of 316 potato lines were screened by Ralstonia solanacearum. The results demonstrated that 6 potato lines were resistant to bacterial wilt, 34 potato lines were moderate resistant to bacterial wilt, 37 potato lines were moderate susceptible to bacterial wilt, 236 potato lines were susceptible to bacterial wilt. It shows that most of wild potato species was susceptible to bacterial wilt and resistant potato material to bacterial wilt is too small.2. We analysed the resistance level in different potato species and hybrid crosses with wild species blood. The results show that a wild species S. morelliforme performance high resistance to bacterial wilt. Three wild species like S. pinnatisectum, S. paucissectum, S. leptophyes showed moderate resistance to bacterial wilt. Eleven wild species like S. stoloniferum, S. albicans showed moderate susceptible resistance to bacterial wilt and seventeen wild species like S. bulbocastanum, S. phureja show susceptible resistance to bacterial wilt. All the hybrid materials and fusion materials showed susceptible resistance to bacterial wilt except wild blood hybrid materials, 3/4 S.tuberosum 1/4 S. bulbocastanum which was resistant to bacterial wilt. The study found that materials in wild potato species S. acaule, S. tuberosum subsp. andigenum, S. commersonii, S. morelliforme were observed obvious resistance segregation.3. Four resistant potato clones MRL79-1, MRL79-2, MRL79 and CMM60-2 were inoculated by nine effector proteins mutants of R. solanacearum. The results found that pathogenicity of UW551-m9 was obviously stronger than wild strain in 3 clones of S. morelliforme. So we suggested that the effector protein Rip9 may be the Avr-effector protein which recognized by resistant materials.