Monokaryotic hyphae germinated from a single spore of the ectomycorrhizal basidiomycete Tricholoma matsutake

• Isolation of monokaryotic hyphae has seldom been documented in Tricholoma matsutake.
• Monokaryons of T. matsutake isolated from spores have been maintained for 9 years.
• Uninucleate monokaryons generated multiple nuclei in a cell during pure culture.
• Most spore isolates exhibited one of the two parent SNP patterns.
• These spore isolates are useful in genetics and breeding of “matsutake” mushrooms.

We document here that monosporous isolates of the ectomycorrhizal basidiomycete Tricholoma matsutake were initially uni- or bi-nucleate. During pure culture, however, many uninucleate isolates became multinucleate. While the parent strain had two patterns of single nucleotide polymorphisms (SNPs) within its single-copy DNA, 19 of 20 monosporous isolates exhibited one of the two parent SNPs, and an isolate that was binucleate upon germination had both, indicating the former were monokaryotic and the latter dikaryotic. Of those, two isolates carrying SNPs different from one another have been predominantly uninucleate for 9 years. These isolates may be useful in genetics/breeding of “matsutake” mushrooms.