白肉灵芝单核菌株交配型位点解析

Analysis of Mating-type Loci of Monokaryotic Strains in Ganoderma leucocontextum

白肉灵芝是具有地域特色的灵芝属物种,因其药用价值显著而备受关注。在白肉灵芝基因组解析的基础上,对同一亲本来源的2个可亲和单核菌株GL72和GL81的交配型位点进行分析。结果显示:白肉灵芝2株单核菌株的A交配型位点与大多数担子菌相似,含有1对HD基因,“头对头”排列。二者的HD基因存在差异,其中GL72菌株HD1基因含有2个双分型核定位信号和HD1特有序列,而GL81菌株HD1基因只含有1个双分型核定位信号;HD2基因编码蛋白中二者同源结构域的α螺旋Ⅰ存在较大差异。A交配型位点侧翼基因在2个单核菌株中也存在较大变异。GL72和GL81菌株的B交配型位点均有8个假定的信息素受体基因,但菌株GL72有9个假定的信息素前体基因,菌株GL81仅发现5个假定的信息素前体基因。解析了白肉灵芝可亲和的单核菌株交配型位点,为其遗传育种奠定了基础。

Due to its medicinal value,Ganoderma leucocontextum,a subspecies of Ganoderma carrying regional characteristics,has attracted much attention.However,the structure of its matingtype loci still remains unknown.In this study,whole genomes of two monokaryotic strains,GL72 and GL81,were sequenced by using the next-generation sequencing and single-molecule real-time sequencing technologies.Based on the genomic information,sequences and structure of mating-type loci of the above two monokaryotic strains were extensively analyzed.Our results revealed clearly that the mat A locus of both strains has one pair of HD genes with a head-to-head direction,which is similar to that of the most basidiomycetes.Within the HD1 gene region,however,it was found that strain GL72 contains two bi-type nuclear localization signal domains and HD1-specific sequences as well while strain GL81 holds only one bi-type nuclear localization signal domain.There also existed some significant differences within the coding sequences of homologousα-helix I domain in HD2 gene between the two strains.Genes flanking the mat A locus varied significantly,moreover,between the two monokaryotic strains.Furthermore,the mat B loci of both strains of GL72 and GL81were found to carry the same number of eight pheromone receptor genes,but strain GL72 had nine putative pheromone precursor genes while strain GL81 had only five.The above differences discovered from the mating-type genes in the compatible monokaryotic strains of G.leucocontextum in this study should provide a theoretical foundation for our genetic studies and Ganoderma breeding in future.