Genetic diversity and antimicrobial activity of endophytic Myrothecium spp. isolated from Calophyllum apetalum and Garcinia morella

Calophyllum apetalum and Garcinia morella, medicinal plants are endemic to Western Ghats, Karnataka, India. Sixteen Myrothecium isolates were obtained from the tissues of bark and twigs of these plants. The purpose of this study was to explore the antimicrobial activity and genetic variability of the endophytic Myrothecium isolates. The antimicrobial activity as well as the genetic diversity of endophytic Myrothecium species was investigated through RAPD, ISSR and ITS sequence analysis. Myrothecium isolates were genotypically compared by RAPD and ISSR techniques, 510 and 189 reproducible polymorphic bands were obtained using 20 RAPD and ten ISSR primers respectively. The isolates grouped into four main clades and subgroups using unweighted pair group method with arithmetic mean cluster analysis. rDNA ITS sequence analysis presented better resolution for characterising the isolates of Myrothecium spp. The clustering patterns of the isolates were almost similar when compared with RAPD and ISSR dendograms. The results signify that RAPD, ISSR and ITS analysis can be employed to distinguish the genetic diversity of the Myrothecium species. The endophytic and pathogenic strains were compared by maximum parsimony, maximum likelihood and neighbour joining methods. One isolate (JX862206) amongst the 16 Myrothecium isolates exhibited potent antibacterial and as well as anti-Candida activity.