Characterization of Magnaporthe grisea populations associated with rice and weeds in Iran

Abstract

In this study, host-specific forms of the blast pathogen Magnaporthe grisea in Iran were characterized from distinct hosts using a combination of molecular and biological assays. A total of 106 isolates of M. grisea were obtained from north of Iran besides of seven international standards mating type (ISMT) tester isolates achieved from France. Population genetically analyzed with selected markers, such as complementation tests of nit mutants and rep-PCR to evaluate such events. Compatible isolates by complementation tests were assigned to the same vegetative compatibility group (VCG) detected as VCG1 to VCG9 among isolates from rice and weeds. During rep-PCR analysis a total of 42 polymorphic banding patterns were scored from 106 isolates which clustered by host with high bootstrap support (72 to 100 %). Genetic structure between rice and weeds isolates differed significantly. Eleven clonal lineages were identified with only two fingerprinting groups for ISMT isolates considering similarity coefficient of approximately 60 % with rice isolates. Additionally, the majority of the isolates from weeds (78.43 %) were gashed from rice isolates in 43 % similarity. Clear differences in cultivar compatibility within and between lineages suggest Distinctive patterns of genetic diversity of host-specific forms of M. grisea populations linked to crop domestication and agricultural intensification.