Natural and artificial hybridization of Agaricus subrufescens Peck (= A. Blazei Murrill sensu Heinemann): lessons from the quasi-alleles of the rDNA ITS1+2 region
Fecha
2006Autor
Versión
Acceso abierto / Sarbide irekia
Tipo
Contribución a congreso / Biltzarrerako ekarpena
Versión
Versión publicada / Argitaratu den bertsioa
Impacto
|
nodoi-noplumx
|
Resumen
Agaricus subrufescens Peck was described from both wild and cultivated specimens
in 1893. It has been sporadically cultivated in various countries since
that time, and is presently an economically important “nutriceutical” food. It
is known by several names, including A. rufotegulis Nauta, A. brasiliensis
Wasser et al., and A. blazei Murrill sensu Heinemann. A long-term study of
diverse isol ...
[++]
Agaricus subrufescens Peck was described from both wild and cultivated specimens
in 1893. It has been sporadically cultivated in various countries since
that time, and is presently an economically important “nutriceutical” food. It
is known by several names, including A. rufotegulis Nauta, A. brasiliensis
Wasser et al., and A. blazei Murrill sensu Heinemann. A long-term study of
diverse isolates and specimens, emphasizing cultural studies and analysis of
rDNA ITS1+2 sequences, strongly indicates that a single phylogenetic entity
exists. Some interpopulational interfertility has also been demonstrated.
Yet the picture is not simple. The species is amphithallic, with complementary
reproductive routes, producing recombinant spores with cryptic karyotic
states and some self-fertility. Sequences from the Americas were always
highly heteromorphic, while those from Hawaii and the UK were homomorphic.
This implies that American isolates may be hybrids between (at least)
two formerly isolated populations. To test that idea, ITS1+2 sequences from
isolate SBS1, an SSI from a California strain, were amplified, cloned and sequenced.
Both allelism and recombination are evident in these 711-713 nt
sequences: 4 (3+1) parental and 11 recombinant sequences were recovered.
The mechanism of fine-scale recombination is unknown (PCR artifacts have
not been ruled out). Recombination events exceeded 1.0 per 700 nt. Physical
linkage was apparent among 11 polymorphic characters distributed along the
ITS1+2. On this basis the parental allelic sequences were deduced, and a
comparison with the homomorphic UK sequence was made. The evidence
suggests that a European-like strain may have contributed one ITS1+2 allele
to an ancestor of the isolate from California. However, if true, “crossovers”
must then occurred prior to the origin of the SBS1 SSI, possibly in the
SBRF progenitor (or its progenitor(s)). [--]
Materias
Agaricus subrufescens Peck
Editor
Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa
Publicado en
Antonio G. Pisabarro and Lucía Ramírez (eds.): VI Meeting on Genetics and Cellular Biology of Basidiomycetes (GCBB-VI). Pamplona: Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa, 2006.
Notas
Resumen de la conferencia presentada al VI Meeting on Genetics and Cellular Biology of Basidiomycetes (GCBB-VI), organizado por y celebrado en la Universidad Pública de Navarra el 3-6 de junio de 2005.