SYSTEMATIC STUDIES ON SPHAEROPSIDALES BY USING PCR-RFLP AND RAPD ANALYSIS
Zhou Yongli Lu Guozhong Liu Weicheng Bai Jinkai (Department of Plant Protection, Shenyang Agricultural University, Shenyang 110161)
PCR-RFLP and RAPD were used to study the systematic relationships among species and genera in Sphaeropsidales for the first time. 24 strains representing 12 species of 4 genera were evaluated by using PCR-RFLP analysis. ITS was amplified and digested with four base restriction enzymes (Alu I, Hha, Msp I, Taq I). The results showed that the length of ITS varied among genera ranging from 540 to 630 bp: Coniothyrium 630 bp, Phyllosticta 560bp, Ascochyta 550bp, Septoria 540 bp. However, the ITS length of each species in the same genus was identical. The restriction digestion patterns were distinctly different among genera, but basically identical among species within the same genus, suggesting that the traditional division for species was perhaps too narrow, and the erection of some species was questionable,PCR-RFLP is useful to identification of uncertain genus. 16 strains of 8 species from 3 genera were amplified with arbitrary primers. The results showed that the patterns were basically identical intraspecifically, but variable interspecifically. This indicates there are genetic differences among species erected previously by traditional criteria.However, whether the differences are distinct enough to separate them at species level needs further study.