Volume 16 Part 1 Article 10: Diverse Retrotransposons in Agaricus bisporus

Volume 16 Part 1 Article 10
Year 2004
Title: Diverse Retrotransposons in Agaricus bisporus
Authors: R.W. Kerrigan, A.J. Velcko Jr., J.L. Thomas, J.S. McGrady, C.M. Chisholm and M.P. Wach

Abstract:

Cultural instability in the cultivated button mushroom, Agaricus bisporus, can result in the spontaneous emergence of vegetative sectors and/or clustered, distorted sporocarps from cultures with a documented history of normal behavior. Available data suggested that clusters may be associated with a transmissible element, presumably of nucleic acid origin. After testing and rejecting simpler hypotheses, we have come to believe that active transposons may be a factor in Agaricus strain instability, including clustering. A preliminary sequencing survey of eight cosmids containing A. bisporus genomic DNA with overrepresented (repeated) sequences yielded partial sequences of at least six new retrotransposons. A majority of copies of these retroelements appear to be fragmented. Evidence from Southern hybridizations, targeted PCR, and RT-PCR indicated that some of these elements were actively transposing. Preliminary results have demonstrated some consistency in altered patterns of targeted PCR products between cluster-cultures and their healthy progenitors. However, further work is needed to determine how consistent such changes are, whether or not they might include global molecular indicators for clustering, and whether or not actively transposing elements play a causal role in clustering or other strain degeneration syndromes.

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