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Phylogeny and PCR identification of the human pathogenic fungus Penicillium marneffei
1Department of Plant Biology, University of California, Berkeley 94720.
Abstract:
The phylogenetic position of the human pathogenic fungus Penicillium marneffei was assessed from the nucleotide sequences of the nuclear and mitochondrial ribosomal DNA regions. Phylogenetic analysis determined that P. marneffei is closely related to species of Penicillium subgenus Biverticillium and sexual Talaromyces species with asexual biverticillate Penicillium states. Knowledge of the phylogenetic position of P. marneffei facilitated the design of unique oligonucleotide primers, from the nuclear ribosomal DNA internal transcribed spacer region, for the specific amplification of P. marneffei DNA. These primers were successful at selectively amplifying DNA from six isolates of P. marneffei and excluding the other species tested, which included Penicillium subgenus Biverticillium and Talaromyces species and several well-known fungal pathogens, namely, Aspergillus fumigatus, Coccidioides immitis, Histoplasma capsulatum, and Pneumocystis carinii. The primers that we have developed for the specific amplification of P. marneffei have the potential to be incorporated in a PCR identification system which could be used for the identification of this pathogenic agent from clinical material.
Insights
Penicillium marneffei, a human fungal pathogen, is closely related to Penicillium subgenus Biverticillium and Talaromyces species. New primers can specifically identify P. marneffei DNA using PCR, aiding clinical diagnosis.
Area of Science:
- Mycology
- Molecular Biology
- Medical Mycology
Background:
- Penicillium marneffei is a significant human pathogenic fungus.
- Accurate identification of P. marneffei is crucial for clinical diagnosis and treatment.
- Understanding its phylogenetic relationships can aid in developing diagnostic tools.
Purpose of the Study:
- To determine the phylogenetic position of Penicillium marneffei.
- To develop specific molecular primers for P. marneffei identification.
- To evaluate the specificity of these primers against related fungal species and known pathogens.
Main Methods:
- Phylogenetic analysis using nucleotide sequences of nuclear and mitochondrial ribosomal DNA.
- Design of oligonucleotide primers targeting the nuclear ribosomal DNA internal transcribed spacer region.
- Polymerase Chain Reaction (PCR) amplification and specificity testing.
Main Results:
- Phylogenetic analysis placed P. marneffei close to Penicillium subgenus Biverticillium and sexual Talaromyces species.
- Novel oligonucleotide primers specifically amplified P. marneffei DNA from six isolates.
- The primers successfully excluded DNA from closely related Penicillium and Talaromyces species, as well as other fungal pathogens.
Conclusions:
- P. marneffei's phylogenetic position is clarified.
- Developed primers enable specific amplification of P. marneffei DNA.
- These primers show potential for a PCR-based diagnostic system for clinical identification of P. marneffei.