Preliminary study on polymorphism and pathogenicity of Phytophthora capsici Leonian in Liaoning

Abstract:

[Objective] The definite relation was found between polymorphism, pathogenicity differentiation of Phytophthora capsici Leonian and regionality in Liaoning Province. [Methods] Using Sequence related Amplified Polymorphism (SRAP) technology, the 25 strains of Phytophthora capsici Leonian in Liaoning were amplified in PCR method and evaluated by clustering analyses of NTSYS-PC. The pathogenic differentiation was researched by root-drenching method, and it was examined with hierarchical cluster combination by SPSS 11.5. [Results] The results showed that the DNA of 25 strains were amplified by 27 primer pairs. A total of 578 bands were identified, of which 548 bands were polymorphic. The percentages of polymorphic fragments of each primer pairs were ranged from 84% to 100%. There were abundant polymorphism clustering analysis showed that the genetic similarity among the 25 strains of Phytophthora capsici Leonian were very high. The similarity coefficients varied from 0.56 to 0.91. They were divided into four groups at 0.68 for similarity coefficient, significant correlations were not obvious among the sources of these strains, and there were not regional characteristics. 80% strains were intermediate pathogenicity. [Conclusion] The tested strains were not significantly regional characteristics, and there was no regularity of pathogenicity differentiation from different areas.