ABSTRACT

BACKGROUND AND OBJECTIVE: The number of fungal species on earth is estimated at about 1.5 million species, among which about 400 species belong to animal and human pathogens. Human pathogenic fungal species are mainly isolated from plant hosts. Studies on multi-host fungi have shown that with changes in physiological pathogenicity, these fungi are able to change their host according to the circumstances they are in. Horizontal gene transfer may play an important role in the evolution of fungal virulence in human hosts.

METHODS: In this retrospective study, Pubmed, Medline, Scopus, Google Scholar, Elsevier, Irandoc, Iranmedex, Magiran, SID, and MEDLIB databases were searched thoroughly. MeSH keywords in our search included the evolution of virulence, pathogenic fungi, human pathogenic fungi, pathogenic plant fungi, horizontal gene transfer, and limited host plants. The related articles, published during 1992-2010, were extracted and retrospectively studied.

FINDINGS: Molecular studies on multi-host fungi confirm the hypothesis of pathogenic fungal evolution from plant hosts to human hosts. The present study evaluated the recent findings on the origin of human pathogenic fungi and host changes from plant to human hosts.

CONCLUSION: By comparing the content and structure of genomes and genes in pathogenic fungi, with different host ranges, penetration methods, and pathogenicity, we will have a better understanding of pathogenic genes and the processes involved in the evolution of the disease.