Phylogenetic analysis of HSP70 gene of Aspergillus fumigatus reveals conservation intra-species and divergence inter-species

Aspergillus fumigatus is a saprophyte fungus, widely spread in a variety of ecologicalniches and the most prevalent aspergilli responsible for human and animal invasiveaspergillosis. The first step to develop novel and efficient therapies is the identificationand understanding of the key tolerance and virulence factors of pathogens. The mainfocus of the present study is to perform the similarity, conservation and phylogeneticanalysis of heat shock protein 70 (HSP70) gene of the fungus A. fumigatus. Therefore,DNA sequence of HSP70 gene was obtained from a native airborne A. fumigatus.Similarity, divergence and conservation of HSP70 gene sequence were assayed andcompared to other strains and fungal species using nucleotide Basic Local AlignmentSearch Tool (BLAST), construction of phylogenetic tree and online analysis tools. Theresults revealed that the most similar aspergilli to the examined A. fumigatus strain wereA. fumigatus non-native strains, Aspergillus clavatus, Aspergillus niger, Aspergillusterreus, and Aspergillus nidulans. Among other fungal genera, Penicillium species werethe most similar fungal genus to A. fumigatus. Moreover, the alignment results revealedhigh levels of similarity and conservation of native A. fumigatus HSP70 gene sequencewith yeasts stress-Seventy subfamily A (SSA) gene sequence from HSP70 family ofgenes and lower similarities with other genes in the family (Ssb, Ssc, HscA, Kar2 andbipA). Penicillium spp. were the most similar fungi to Aspergillus species byphylogenetic analysis of HSP70 sequence. Other molds, yeasts and yeast-like fungi wereplaced in more distanced clades. In general, fungal HSP70 sequence analysis could directus to make a better understanding of thermo-tolerance in different fungal species.