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

Document Type : Original Articles


1 Mycology Research Center, Faculty of Veterinary Medicine, University of Tehran, Tehran, Iran

2 Mycology Research Center, Faculty of Veterinary Medicine, University of Tehran, Tehran, Iran.

3 Department of Microbiology, Faculty of Veterinary Medicine, University of Tehran, Tehran, Iran.


Aspergillus fumigatus is a saprophyte fungus, widely spread in a variety of ecological
niches and the most prevalent aspergilli responsible for human and animal invasive
aspergillosis. The first step to develop novel and efficient therapies is the identification
and understanding of the key tolerance and virulence factors of pathogens. The main
focus of the present study is to perform the similarity, conservation and phylogenetic
analysis 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 and
compared to other strains and fungal species using nucleotide Basic Local Alignment
Search Tool (BLAST), construction of phylogenetic tree and online analysis tools. The
results revealed that the most similar aspergilli to the examined A. fumigatus strain were
A. fumigatus non-native strains, Aspergillus clavatus, Aspergillus niger, Aspergillus
terreus, and Aspergillus nidulans. Among other fungal genera, Penicillium species were
the most similar fungal genus to A. fumigatus. Moreover, the alignment results revealed
high levels of similarity and conservation of native A. fumigatus HSP70 gene sequence
with yeasts stress-Seventy subfamily A (SSA) gene sequence from HSP70 family of
genes and lower similarities with other genes in the family (Ssb, Ssc, HscA, Kar2 and
bipA). Penicillium spp. were the most similar fungi to Aspergillus species by
phylogenetic analysis of HSP70 sequence. Other molds, yeasts and yeast-like fungi were
placed in more distanced clades. In general, fungal HSP70 sequence analysis could direct
us to make a better understanding of thermo-tolerance in different fungal species.


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