Volume 12 Part 1 Article 6: Biotechnological Advances in Mushroom Science

Volume 12 Part 1 Article 6
Year 1989
Title: Biotechnological Advances in Mushroom Science
Authors: P.A. Horgen and J.B. Anderson

Abstract:

Despite the economic importance of Agaricus brunnescens, in comparison to other vegetable crops, little effort has been made to genetically improve the strains used for commercial production. One of the major reasons for the lack of a traditional “crops breeding program” for A. brunnescens is the secondarily homothallic nature of its life cycle. At no stage during the life history of A. brunnescens do we find a thai lus that is uninucleate. The isolation of parental types among single spore isolates is a laborious activity. Furthermore, the methods used to verify the isolation of a parental type (homokaryon) is again time consuming and difficult to confirm. There have been few reliable genetic markers in A. brunnescens. When successful commercial strains of A. brunnescens are selected, it is often based only on phenotype with no convenient methodology developed to “fingerprint or mark” successful strains for proprietary purposes.

Although many of the characteristics of the commercial strains in production today are highly desirable, in many instances, there is still room for improvement. The inherent short shelf life, narrow range for temperature variation during growth or fruiting and the susceptability to disease are a few parameters where improvement would be beneficial. Some of these traits have been identified in wild isolates of Agaricus species (Dielemanvan Zaayen 1972). The challenge to mushroom scientists is to identify and develop the means to transfer these desirable traits into the higher yielding, commercially more acceptable A. brunnescens. We believe that Agaricus is an excellent example of an agriculturally important organism which will benefit tremendously from biotechnology.

We have utilized restriction fragment length polymorphisms (RFLPs) as unambiguous genetic markers. We suggest that RFLPs can be used to fingerprint successful strains for proprietary purposes. Furthermore, a successful methodology for homokaryon 63 isolation has been reported and intraspecies hybridization has been confirmed. We have studied and characterized the mitochondrial genome of Agaricus in hopes of utilizing cytoplasmic inheritance in our breeding program. One of our long term objectives is to develop a gene transfer system for Agaricus and some strategies will be discussed.

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