Identification of three fruit-rot fungi of banana by 28s ribosomal DNA sequencing

Abstract

The aim of present investigation was to identify three fruit-rot fungi- Macrophomina phaseolina (Tassi) Goid, Fusarium oxysporum (Schlechtend) and Nigrospora oryzae (Berk and Br.) Petch isolated from banana fruits [Rasthali (Silk AAB) and Cavendish (AAA) varieties]. Out of different fungal genera isolated, the above fungi were responsible for maximum loss of banana fruits as they spread rapidly into the fruit pulp and deteriorated the fruits. The amplification studies of fragment of D2 region of LSU (Large subunit 28S rDNA gene of three fungi understudy was carried out using PCR technique. Based on the nucleotide homology and phylogenetic analysis, the fungus M. phaseolina was identified as M. phaseolina strain R-4242 sp. (Genbank accession number: FJ415068.1), F. oxysporum as Fusarium sp.QJC-1403 5.8S ribosomal RNA gene sp. (Genbank accession number: EU193176.1) and N. oryzae as N. oryzae NRRL: 54030 sp. (Genbank accession number: GQ328855.1). Nucleic acid sequencing provides more objective separation of genera and species than that provided by the conventional techniques. This technique can best be used for the identification of organisms that could not be identified satisfactorily by their microscopic morphological features. Genetic characterization of plant pathogens prevalent in an area is necessary for efficient management and increased crop productivity. The data presented may help researchers to understand the host-pathogen interactions indetail in banana, to design effective strategies for deployment of resistant genes in banana ( Musa paradisiaca L.) growing regions in the country and worldwide.