Genetic relationships in the natural population of Pholiota nameko from Japan based on DNA polymorphisms

Abstract

This study characterized the genetic relationships in the natural population of Pholiota nameko (Strophariaceae) from Japan based on the RFLPs of two regions of nuclear rDNA (ITS and IGS) and mitochondrial DNA and the RAPD profile of nuclear DNA. No intraspecific polymorphism in rDNA was found among 36 isolates of P. nameko used. By contrast, digests of mtDNAs by endonucleases HindIII and BglII produced RFLP patterns that distinguished all isolates except for 2, and clustered 36 wild isolates phenetically into three major similarity groups. However, these groups as obtained by analysis of mtDNA RFLPs did not reflect the geographic origin of the isolates. In RAPD analysis of nuclear DNA using three kinds of primers, every isolate showed its own distinct RAPD profile, but all isolates were clustered only into a large similarity group by phylogenetic analysis based on the RAPD profile. From these results, it is suggested that wild isolates of P. nameko distributed in Japan form a continuous genetic population that has conserved the genetic diversity.

Phylogenetic position of Pholiota nameko in the genus Pholiota inferred from restriction analysis of ribosomal DNA

“…By the RFLP analysis for 26S rDNA of P. nameko, we could confirm that there is no intraspecific variation of this fungus in rDNA following the previous study (Obatake et al 2002). This result is advantageous in the analysis of the phylogeny target position of P. nameko for the rDNA in the genus Pholiota.…”

“…No RFLPs were shown in restriction digests with AluI for the 5Ј-half of 26S rDNA and with two enzymes, HaeIII and TaqI, for the 3Ј-half of 26S rDNA. When RFLPs in each region of 26S rDNA of all the isolates examined were compared by combining the restriction patterns obtained with four enzymes, no RFLP within all 36 isolates of P. nameko was shown in both regions of 26S rDNA in addition to the results of ITS and IGS regions described previously (Obatake et al 2002).…”

“…Previously, we have determined that no intraspecific variation exists in ITS and IGS regions of rDNA in the natural population of P. nameko from Japan (Obatake et al 2002). In this study, we carried out further analysis of polymorphisms in the rDNA from eight closely related species of P. nameko by using PCR-RFLP markers to estimate the phylogenetic position of P. nameko in the genus Pholiota.…”

Genetic variation in cultivated strains of Agaricus blazei

“…Sacc. (Hintz et al 1985), L. edodes (Fukuda et al 1994), P. ostreatus , and P. nameko (Obatake et al 2002). However, no variation in the migration of the isozyme bands and the restriction fragments by digestion with EcoRI and EcoRV was detected among the seven strains.…”

“…Pegler (Fukuda and Tokimoto 1991), Pleurotus ostreatus (Jacq: Fr.) Kummer (Matsumoto and FukumasaNakai 1995), and Pholiota nameko (T. Ito) S. Ito and Imai (Obatake et al 2002). These studies provide important information on mushroom breeding.…”