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Pak. J. Bot., 44(4): 1267-1270, 2012.

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MOLECULAR POLYMORPHISM AND PHYLOGENETIC RELATIONSHIP OF SOME ALTERNARIA ALTERNATA ISOLATES

GHAZALA NASIM, SAMIA KHAN AND IBATSAM KHOKHAR

Abstract: Random amplified polymorphic DNA technique (RAPD) was used to determine the finger print of 10 isolates of  Alternaria alternata collected from First Fungal Culture Bank of Pakistan (FCBP), Institute of Agricultural Sciences, University of Punjab, Lahore. Conventional methods often do not distinguish between the isolates of the same species. Therefore DNA based method was applied to find if the isolates differ significantly from each other. The RAPDs method was choosen because of its simplicity and ability to differentiate the isolates. This work was concentrated on Alternaria alternata because they are common pathogens of different plants and are particularly difficult to distinguish with conventional methods.DNA was isolated from the fungal hyphae of the isolates which were formerly purified by the single spore method. Five out of ten isolates were able to produce clear DNA bands. Those isolates were Aa1, Aa2, Aa3, Aa4, and Aa5. A total of 22 bands ranging in size from 250-1200 bp were generated by the primer GL-A-01. Nineteen of these 22 bands (86.36%) were monomorphic. Only three bands with sizes of 250, 600 and 1200 bp produced by primer GL-A-01, were polymorphic. Cluster analysis of similarity between band pairs showed that the fungal isolates were clustered in two distinctive groups. RAPD was found to be an important tool to identify genetic dissimilarities between different isolates of Alternaria alternata.

Institute of Agricultural Sciences, University of the Punjab, Quaid-e-Azam Campus, Lahore-54590.

Corresponding email: ghazalanasim@hotmail.com