RAPD profile and rDNA sequence analysis of <i style="">Talaromyces flavus</i> and <i style="">Trichoderma</i> species

Abstract

<i style="">Talaromyces flavus</i> isolated from paddy rhizosphere exhibited phosphate solubilizing activity <i style="">in vitro</i> and positively influenced the growth of <i style="">Oryza sativa</i>, <i style="">Cicer arietinum</i> and <i style="">Vigna radiata</i> under green house conditions. Besides, isolates of <i style="">Trichoderma harzianum</i> and <i style="">T. asperellum</i> obtained from agricultural field of Darjeeling hills showed antifungal activities against fungal pathogens. Phylogenetic analysis of all these isolates were carried out by sequencing the internal transcribed spacer regions (ITS1 & ITS4) of the ribosomal DNA of <i style="">T. flavus</i> and <i style="">T. harzianum</i> using universal primers. The sequences were aligned against ex-type strain sequences from NCBI GenBank. Genetic relatedness among the isolates was studied using random decamer primers. UPGMA cluster analysis showed that the similarity coefficient ranged from 0.37 to 1 for <i style="">T. flavus</i> and 0.68 to 1 for <i style="">T. harzianum</i>. The open reading frame (ORF) analysis of 18S rDNA sequence of <i style="">T. harzianum </i>revealed that the sequence contains in total of four ORFs, encoding 159 amino acids with an estimated molecular mass of 17.84 kDa. The sequences of ITS1 region have been used as the reference sequence, which may be used for future study involving the identification and taxonomy of both <i style="">T. flavus</i> and <i style="">Trichoderma</i> isolates.