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Isolation and genotype analyses of ascospores produced between genetically different Arthroderma benhamiae strains
Masako Kawasaki1, Takashi Mochizuki, Hiroshi Ishizaki
1Department of Dermatology, Kanazawa Medical University, Uchinada, Ishikawa 920-0293, Japan.
Abstract:
Thirty-one single ascospore cultures were obtained from one ascoma produced in mating of RV 26678 (+) (Institut de Medicine Tropicale, Antwerp, Belgium) and KMU 4169 (-) (Dept. Dermatology, Kanazawa Medical University, Uchinada, Japan), which are genetically different strains of Arthroderma benhamiae. The isolation was performed with the aid of an inverted microscope and a binocular microscope. The internal transcribed spacer (ITS) regions of the nuclear ribosomal RNA gene of all the ascospore cultures were analyzed by restriction fragment length polymorphism (RFLP) with the restriction enzyme HinfI. The mating types of all the single-ascospore cultures were also checked. Eight cultures had mating type (+) and RV 26678 genotype, 10 had mating type (-) and RV 26678 genotype, 6 had mating type (+) and KMU 4169 genotype and 7 had mating type (-) and KMU 4169 genotype. There was no linkage between the mating types and the genotypes, implying that the genes control the mating behavior and the genes of ribosomal RNA are on different chromosomes from each other. The hybrids comprised half of the isolates and so they were actually from the ascospores and not from the microconidia or the peridial hyphae.
Insights
Genetic analysis of Arthroderma benhamiae mating revealed no linkage between mating types and ribosomal RNA gene genotypes. This suggests independent chromosomal inheritance for these traits in this dermatophyte species.
Area of Science:
- Medical Mycology
- Genetics
- Molecular Biology
Background:
- Arthroderma benhamiae is a dermatophyte species known for causing skin infections.
- Understanding the genetic basis of mating and ribosomal RNA (rRNA) gene inheritance is crucial for fungal research.
Purpose of the Study:
- To investigate the genetic linkage between mating types and internal transcribed spacer (ITS) regions of nuclear ribosomal RNA genes in Arthroderma benhamiae.
- To determine the chromosomal segregation patterns of these genetic elements during sexual reproduction.
Main Methods:
- Isolation of single ascospore cultures from a controlled mating of Arthroderma benhamiae strains.
- Analysis of internal transcribed spacer (ITS) regions using restriction fragment length polymorphism (RFLP) with the HinfI enzyme.
- Genotyping of mating types for all resulting ascospore cultures.
Main Results:
- Thirty-one single ascospore cultures were analyzed.
- Restriction fragment length polymorphism (RFLP) analysis of ITS regions and mating type checks were performed.
- No linkage was observed between mating types and the analyzed ribosomal RNA gene genotypes, indicating independent assortment.
Conclusions:
- The genes controlling mating behavior and the genes of ribosomal RNA are located on different chromosomes.
- This independent assortment facilitates genetic diversity within Arthroderma benhamiae populations.
- The study confirms that the analyzed isolates were true hybrids derived from ascospores.