Breeding of New Strains of Mushroom by Basidiospore Chemical Mutagenesis

Abstract

Chemical mutagenesis of basidiospores of Hypsizygus marmoreus generated new mushroom strains. The basidospores were treated with methanesulfonate methylester, an alkylating agent, to yield 400 mutant monokaryotic mycelia. Twenty fast-growing mycelia were selected and mated each other by hyphal fusion. Fifty out of the 190 matings were successful (mating rate of 26.3%), judged by the formation of clamp connections. The mutant dikaryons were cultivated to investigate their morphological and cultivation characteristics. Mutant strains No. 3 and No. 5 showed 10% and 6% increase in fruiting body production, respectively. Eight mutant strains showed delayed and reduced primordia formation, resulting in the reduced production yield with prolonged cultivation period. The number of the fruiting bodies of mutant No. 31, which displayed reduced primordial formation, was only 15, compared to the parental number of 65. Another interesting phenotype was a fruiting body with a flattened stipe and pileus. Dikaryons generated by mating with the mutant spore No. 14 produced flat fruiting bodies. Further molecular biological studies will provide details of the mechanism. This work shows that the chemical mutagenesis approach is highly utilizable in the development of mushroom strains as well as in the generation of resources for molecular genetic studies.

Isolation and Characterization of Monokaryotic Strains ofLentinula edodesShowing Higher Fruiting Rate and Better Fruiting Body Production

“…To generate more genetic diversity, the basidiospores were treated with 0.01 vol% methymethane sulfonate (MMS; Sigma-Aldrich Co., St. Louis, MO, USA), an alkylating agent, using a previously described method [ 13 ]. The survival rate of the germinated spores was 93% at 0.01 vol% MMS.…”

“…When the newly formed dikaryotic mycelial strains are ready, they are cultivated to produce fruiting bodies, which are used to screen for strains with good commercial and cultivation traits. However, dikaryotic strains do not always produce fruiting bodies [ 12 , 13 ]. The fruiting rate of the newly formed strain, which is the ratio of fruiting body-forming strains per total dikaryotic strains, is highly dependent on environmental conditions and mushroom species.…”

“…Sixteen and 15 alleles at loci A and B, respectively, were reported from 12 strains of Pleurotus eryngii , suggesting that P. eryngii can have at least 240 (15 × 16) different compatible mating pairs when different pairs of monokaryotic strains are used [ 3 ]. Random mutagenesis by chemical or physical means does not change the mating rate, but can be applied to enhance the diversity of the genetic pool [ 13 , 17 , 18 ]. A temperature-adapted strain of P. ostreatus and a high β-glucan producing Hypsizygus marmoreus were recently developed using a combination of mycelial mating and chemical mutagenesis [ 17 , 19 ].…”

Strain improvement in Pleurotus Ostreatus using UV light and ethyl methyl sulfonate as mutagens

“…However, no other significant variation was recorded in terms of biological efficiency in any of the mutants (Table 1). Lee et al (2011) observed that basidiospores treated with chemical mutagens showed a change in primordial initiation resulting in reduced yield. Strain improvement in three isolates of P. ostreatus viz.…”

Generation and Evaluation of High β-Glucan Producing Mutant Strains ofSparassis crispa

“…In order to use the mycelia of S. crispa as a β-glucan producer, development of a fast-growing strain with high β-glucan content became essential. Our previous work provided evidence indicating that chemical mutagenesis was an effective method for generation of mutant strains with desirable properties [ 15 ]. Treatment of basidiospores with an alkylating agent and subsequent mating resulted in generation of a mushroom with diverse morphological characteristics.…”