Data from: Characterization and distribution of mating-type genes of the turfgrass pathogen Sclerotinia homoeocarpa on a global scale

Sclerotinia homoeocarpa F.T. Bennett is a filamentous member of Ascomycota that causes dollar spot, the most economically important disease of turfgrass worldwide. We sequenced and characterized the mating-type (MAT) locus of four recently-collected contemporary strains causing dollar spot, four historical type strains used to describe the fungus, and three species of Rutstroemiaceae. Moreover, we developed a multiplex PCR assay to screen 1019 contemporary isolates for mating-type. The organization of the MAT loci of all strains examined could be classified into one of four categories: (1) putatively heterothallic, as exemplified by all contemporary strains and three of four historical type strains; (2) putatively heterothallic with a deleted putative gene in the MAT1-2 idiomorph, as detected in strains from two recently-collected populations in the United Kingdom that show more similarity to historical strains; (3) putatively homothallic with close physical linkage between MAT1-1-1 and MAT1-2-1, as found in one historical type strain of S. homoeocarpa and two strains of Rutstroemia cuniculi; and (4) an unresolved but apparently homothallic organization in which strains contained both MAT1-1-1 and MAT1-2-1 but linkage between these genes and between the two flanking genes could not be confirmed, as identified in R. paludosa and Poculum henningsianum. In contemporary S. homoeocarpa populations there was no significant difference in the frequency of the two mating types in clone-corrected samples when analyzed on regional and local scales, suggesting sex may be possible in this pathogen. However, two isolates from Italy and twenty from California were heterokaryotic for both complete heterothallic MAT idiomorphs. Results from this study contribute to knowledge about mating systems in filamentous fungi and enhance our understanding of the evolution and biology of an important plant pathogen.

铜钱斑病菌（Sclerotinia homoeocarpa F.T. Bennett）是隶属于子囊菌门（Ascomycota）的丝状真菌，可引发钱斑病——这是全球范围内对草坪草经济危害最为严重的病害之一。本研究对4株近年分离的当代致病菌株、4株用于该真菌物种描述的历史模式菌株，以及柔膜菌科（Rutstroemiaceae）的3个物种的交配型（MAT）基因座进行了测序与特征解析。此外，我们开发了多重PCR（multiplex PCR）检测体系，用于对1019株当代分离菌株进行交配型筛查。所有受试菌株的MAT基因座结构可划分为以下四类：(1) 推定异宗配合型：以全部当代菌株及4株历史模式菌株中的3株为典型代表；(2) MAT1-2异形体（idiomorph）中存在推定基因缺失的推定异宗配合型：该类型在英国两个近年采集的种群的菌株中被检出，此类菌株与历史模式菌株的亲缘关系更为接近；(3) MAT1-1-1与MAT1-2-1基因存在紧密物理连锁的推定同宗配合型：该类型见于S. homoeocarpa的1株历史模式菌株及2株兔形柔膜菌（Rutstroemia cuniculi）菌株；(4) 结构未明确但外观为同宗配合型：此类菌株同时携带MAT1-1-1与MAT1-2-1基因，但无法证实这两个基因自身以及二者两侧翼基因间存在连锁关系，该类型在沼泽柔膜菌（R. paludosa）与亨宁斯杯盘菌（Poculum henningsianum）中被发现。在当代S. homoeocarpa种群中，经克隆校正（clone-corrected）的样本内，两种交配型的频率在区域及局域尺度下均无显著差异，暗示该病原菌具备有性生殖的潜在可能。然而，来自意大利的2株分离物与来自加利福尼亚州的20株分离物，同时携带完整异宗配合的两类MAT异形体，呈异核（heterokaryotic）状态。本研究结果丰富了丝状真菌交配系统的相关认知，并加深了对这一重要植物病原菌的演化与生物学特性的理解。