Diversity assessment of indigenous and exotic italicDiaporthe/italic species associated with various crops using ISSR, URP and SRAP markers

摘要

Genetic diversity among the isolates representing five Diaporthe (syn: Phomopsis ) species isolated from seeds of various crops representing both exotic as well as indigenous collections from India was analyzed using molecular markers, viz., inter-simple sequence repeats (ISSR), universal rice primers (URP) and sequence-related amplified polymorphism (SRAP). The isolates of Diaporthe showed differences among themselves by clustering distinctly which otherwise could not be distinguished with morphological characterization. The total number of polymorphic alleles was 323 with a range of 0.1–3.4 kb in ISSR, 293 with a range of 0.08–3.4 kb in URP and 293 with a range of 0.08–3.4 kb in SRAP. Genetic diversity determining parameters like polymorphic information content, expected heterozygosity, Shannon’s information index, effective multiplex ratio, and marker index was highest in URP markers. Unweighted pair group method with arithmetic average (UPGMA) analysis clustered the isolates into 2 major groups at 61% genetic similarity during combined analysis using these three sets of markers. Among molecular markers, URP markers showed superiority in detecting genetic diversity by differentiating both domestic and exotic isolates representing various species of Diaporthe . Exotic isolates of D. phaseolorum collected from jatropha showed the highest similarity whereas, indigenous isolates of D. phaseolorum isolated from soybean showed the highest level of variation. The isolates did not correspond to agro-ecological regions and the crop origin. This will be helpful in developing species-specific primers for detection of Diaporthe species.