Phylogenetic investigation of endophytic Fusarium strain producing antimicrobial metabolite isolated from Himalayan Yew Bark

An endophytic fungus, Fusarium sp. was isolated from yew bark of eastern Himalaya. Ethyl acetate extract from its fermentation broth displayed considerable antimicrobial activity against three Gram-positive bacteria (Staphylococcus aureus, Bacillus subtilis and Staphylococcus epidermidis), three Gram-negative bacteria (Klebsiella pneumoniae, Escherichia coli and Shigella flexneri) and two pathogenic fungi (Candida albicans and Candida tropicalis). The metabolite showed highest inhibition zone against K. pneumoniae (27 mm) and lowest against C. albicans (10 mm). Based on BLAST search analysis of ITS rDNA sequence, the fungus was identified as Fusarium solani (Mart.) Sacc. Phylogenetic trees were generated by four different methods. Phylogenetic tree generated by UPGMA method was used to establish possible phylogenetic relationships of the fungus with other F. solani isolates those exist as endophytes, pathogens and saprotrophs taken from database. The generated tree showed that all F. solani strains have a common endophytic ancestry which gave rise to six clades that radiate into four evolutionary lineages. The possible phylogenetic relationships of F. solani that exist in different lifestyle have been discussed in each clade.