Applied Microbiology and Biotechnology

, Volume 100, Issue 2, pp 781–796

Spore behaviors reveal a category of mating-competent infertile heterokaryons in the offspring of the medicinal fungus Agaricus subrufescens

  • Manuela Rocha de Brito
  • Marie Foulongne-Oriol
  • Magalie Moinard
  • Eustáquio Souza Dias
  • Jean-Michel Savoie
  • Philippe Callac
Applied Genetics and Molecular Biotechnology

DOI: 10.1007/s00253-015-7070-7

Cite this article as:
Rocha de Brito, M., Foulongne-Oriol, M., Moinard, M. et al. Appl Microbiol Biotechnol (2016) 100: 781. doi:10.1007/s00253-015-7070-7

Abstract

Strain breeding is much less advanced in the edible and medicinal species Agaricus subrufescens than in Agaricus bisporus, the button mushroom. Both species have a unifactorial system of sexual incompatibility, a mating type locus tightly linked to a centromere, and basidia producing both homokaryotic (n) and heterokaryotic (n + n) spores. In A. bisporus, breeding is mainly based on direct selection among the heterokaryotic offspring and on hybridization between homokaryotic offspring. The parental heterozygosity is highly maintained in the heterokaryotic offspring due to suppression of recombination and preferential pairing in the spores of nuclei, each one per second meiotic divisions; such “non-sister nuclei” heterokaryons are fertile. In A. subrufescens, recent studies revealed that recombination is not suppressed and that nuclei from the same second meiotic division can also be paired in a spore that give rise to a “sister nuclei” heterokaryon in which the nuclei bear the same mating type allele. The objective of the present work was to investigate the potential function of the different categories of spores in A. subrufescens and their possible use in a genetic breeding program. Using eight co-dominant molecular markers, we found that half of the offspring of the A. subrufescens strain WC837 were heterokaryotic, one quarter of them being sister nuclei heterokaryons. These heterokaryons were infertile and behaved like homokaryons, being even able to cross between each other. In contrast, non-sister nuclei heterokaryons could fruit but inconsistently due to inbreeding depression. Potential roles of these two categories of heterokaryons in nature and consequences for strain breeding are discussed.

Keywords

Mushroom Pseudohomothallism Buller phenomenon Life cycle Breeding program 

Supplementary material

253_2015_7070_MOESM1_ESM.pdf (184 kb)
ESM 1(PDF 183 kb)

Funding information

Funder NameGrant NumberFunding Note
Programa de Doutorado Sanduiche no Exterior
  • PDSE-CAPES 13006-12-6
bilateral cooperation France/Mexico
  • ANR-09-BLAN-0391-01/project 115790 CONACYT

Copyright information

© Springer-Verlag Berlin Heidelberg 2015

Authors and Affiliations

  • Manuela Rocha de Brito
    • 1
    • 2
  • Marie Foulongne-Oriol
    • 1
  • Magalie Moinard
    • 1
  • Eustáquio Souza Dias
    • 2
  • Jean-Michel Savoie
    • 1
  • Philippe Callac
    • 1
  1. 1.INRA, UR1264 MycSA, Mycologie et Sécurité des AlimentsVillenave d’Ornon CedexFrance
  2. 2.Departamento de BiologiaUFLA, Universidade Federal de LavrasLavrasBrazil

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