Milgroom Michael G, Sotirovski Kiril, Risteski Mihajlo, Brewer Marin Talbot
Department of Plant Pathology and Plant-Microbe Biology, Cornell University, Ithaca, NY 14853, USA.
Fungal Genet Biol. 2009 Nov;46(11):849-54. doi: 10.1016/j.fgb.2009.07.007. Epub 2009 Jul 27.
Evidence for parasexuality in natural populations of haploid fungi requires the demonstration of diploids or heterokaryons and recombinant genotypes in the absence of sex. We studied clonal populations of the chestnut blight fungus, Cryphonectria parasitica, in southeastern Europe and found evidence of parasexuality in two locations. In Osoj, Macedonia, we found one isolate (Os05-66) that had two alleles at six codominant loci, giving a haplotype that was a composite of two clones in this population. Six single-conidial isolates from Os05-66 had two alleles at some loci, suggesting partial diploidy or aneuploidy, and we found four recombinant haplotypes among single-conidial isolates from hyphal-tip isolates of the same isolate. In Teano, Italy, we found two heterokaryon isolates that were partial composites of two dominant clones. Single-conidial isolates from hyphal-tip isolates had recombinant haplotypes. These results provide evidence that is consistent with the hypothesis of parasexuality in C. parasitica in Europe, similar to an earlier report in a natural population in the USA.
在单倍体真菌的自然种群中，准性生殖的证据需要证明在没有有性生殖的情况下存在二倍体或异核体以及重组基因型。我们研究了欧洲东南部栗疫病菌（Cryphonectria parasitica）的克隆种群，并在两个地点发现了准性生殖的证据。在马其顿的奥索伊，我们发现一个分离株（Os05 - 66）在六个共显性位点有两个等位基因，产生的单倍型是该种群中两个克隆的组合。来自Os05 - 66的六个单分生孢子分离株在某些位点有两个等位基因，表明存在部分二倍体或非整倍体，并且我们在来自同一分离株菌丝尖端分离物的单分生孢子分离株中发现了四种重组单倍型。在意大利的蒂亚诺，我们发现了两个异核体分离株，它们是两个优势克隆的部分组合。来自菌丝尖端分离物的单分生孢子分离株具有重组单倍型。这些结果提供的证据与欧洲栗疫病菌准性生殖的假设一致，类似于美国一个自然种群的早期报告。
