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  • ThesisItemOpen Access
    Profiling of Avirulence Genes, Transposable Elements, Mating Type Alleles and Virulence Analysis in Magnaporthe oryzae Isolates
    (University of Agricultural Science, Dharwad, 2016-02) Fathy, Khaled; Prashanthi S. K.
    Magnaporthe oryzae (Couch & Khon) is one the devastating pathogen causing blast disease in rice crop. Ninety seven isolates of M. oryzae from different locations of south India collected from various varieties were characterized. Presence/Absence polymorphism for eight avirulence genes were analysed in 97 isolates. Avr-ACE1 was distributed in 74 isolates accounting highest frequency of 72.28 per cent, followed by Avr-PWL2 57 with 58.76 per cent and Avr-Piz-t with 53.60 per cent. Avr-Pi9 was present in 47 isolates accounting 48.45 per cent distribution. Avr-Pi9 partial gene coding for secretary protein was sequenced for nine isolates. Transposable elements distributed on chromosome seven were studied for polymorphism among 97 isolates. Mg-SINE was distributed more frequently in singletons than other families. Mg-SINE 7-125-M1 showed 57.73 per cent amplification whereas Mg-SINE 7-193-M3 showed least frequency. Mating type of all isolates was tested. Forty six isolates showed mating type MAT1-1 allele (male fertile), 42 isolates amplified mating type MAT1-2 allele (female fertile) and 7 isolates Mo-si-076a, Mo-si-084, Mo-si-007, Mo-si-215, Mo-si-15c, Mo-si-53 and Mo-si-98a were hermaphrodite in nature. Virulence frequency analysis of 97 isolates on LTH monogenic lines containing blast resistance genes indicated that Pik-p, Pik-s, Pik-h, Piz-t, Pita, Pish and Pi9 resistance genes had less matching virulences in the pathogen population studied in this investigation. Isolate Mo-si-206 containing Avr-Pi9, Mo-si-209 containing Avr-Pi20 avirulence gene and Mo-si-076b containing Avr-Pik-m. Two isolates Mo-si-100 and Mo-si-030 showed virulence reaction on all monogenic lines.