Genetic diversity and population structure among isolates of the brown spot fungus, Bipolaris oryzae, as revealed by inter-simple sequence repeats (ISSR)

Abstract

Bipolaris oryzae, the rice brown spot fungus is one of the pathological threats to rice crop worldwide. The genetic diversity among the Indian isolates of brown spot pathogen was studied using inter-simple sequence repeats (ISSR). Considerable intraspecific variability among the isolates of B. oryzae was revealed. Eighty-seven (87) highly reproducible fragments were amplified in all 69 isolates with an average of 13.8 markers per primer. Polymorphism range shown by ISSR primers was 83.33 to 95.45%, while the range of total loci scored was from 6 to 22. The molecular weight of scorable loci ranged from 150 to 2600 bp. The results obtained confirmed the genetic diversity of rice brown spot fungus among samples under study. The present study suggests that ISSR markers can be used as robust molecular markers for the population genetics, epidemiological and ecological studies of B. oryzae that will aid in designing improved methods for management of the rice brown spot disease.

Keywords: Bipolaris oryzae, rice brown spot, inter-simple sequence repeats (ISSR), dendrogram, polymorphism

African Journal of Biotechnology, Vol. 13(2), pp. 238-244, 8 January, 2014