Aims: Molecular characterization of commercially important group of xylanase producing thermophilic/thermotolerant fungi.
Methods and results: DNA from 16 thermophilic/thermotolerant fungal isolates was amplified by PCR using three sets of primers: (i) internal transcribed spacer sequence (ITSI-5.8S-ITSII), (ii) D1/D2 hyper variable region of 26S rDNA and (iii) 18S rDNA region. The amplified products of internal transcribed spacers (ITS) and D1/D2 region were sequenced and analysed using CLUSTALX, whereas, amplified 18S rDNA region was subjected to RFLP analysis based on restriction digestion with RsaI, MboI and Hinf I.
Conclusions: The sequence based analyses of ITSI-5.8S-ITSII as compared with D1/D2 region of 26-28S rDNA was found to be a better tool for phylogenetic resolution of thermophilic/thermotolerant fungi. The ITSI-5.8S-ITSII sequence-based dendrogram indicates an early divergence of the alkaline active xylanase producing thermophilic fungal strains.
Significance and impact of the study: This study was the first report on phylogenetic characterization of thermophilic/thermotolerant fungi.