Department of Genetics, Forestry and Agricultural Biotechnology Institute, University of Pretoria, Private Bag X20, Hatfield, Pretoria 0028, South Africa; Crop Protection Division, Vegetable and Ornamental Plant Institute, Agricultural Research Council, Private Bag X293, Pretoria 0001, South Africa.
Department of Genetics, Forestry and Agricultural Biotechnology Institute, University of Pretoria, Private Bag X20, Hatfield, Pretoria 0028, South Africa.
Fungal Genet Biol. 2014 Jan;62:55-61. doi: 10.1016/j.fgb.2013.10.013. Epub 2013 Nov 9.
Diplodia pinea (=Sphaeropsis sapinea) is a well-known and economically important latent pathogen of Pinus spp. in many parts of the world. Despite intensive scrutiny, its sexual state has never been observed and the fungus has thus been considered exclusively asexual. It was, therefore, surprising that a recent population genetics study showed high genotypic diversity and random association of alleles in a number of populations, suggesting that the pathogen has a cryptic sexual stage. Using the genome sequence of two individual D. pinea isolates, we interrogated the structure of the MAT locus in this fungus. The results suggested that D. pinea is heterothallic (self-sterile) with complete and apparently functional copies of the MAT genes containing the α-1 and HMG domains present in different isolates. In addition to the MAT1-2-1 and MAT1-1-1 genes, we found a MAT1-1-4 gene in the MAT1-1 idiomorph and a novel MAT1-2-5 gene in the MAT1-2 idiomorph. Importantly, the frequencies of occurrence of both idiomorphs in populations examined were not significantly different from a 1:1 ratio, which would be expected in sexually reproducing populations. Although the sexual state has never been observed, the results strongly suggest that D. pinea has a cryptic, heterothallic sexual cycle.
栓皮栎长喙壳菌（Diplodia pinea=Sphaeropsis sapinea）是世界许多地区松属树种的一种知名且具有重要经济意义的潜伏病原菌。尽管经过深入研究，但从未观察到其有性状态，因此该真菌一直被认为是无性的。然而，最近的一项种群遗传学研究显示，在许多种群中存在高基因型多样性和等位基因的随机关联，这表明该病原菌具有隐生的有性阶段，这令人感到惊讶。利用两个单独的栓皮栎长喙壳菌分离株的基因组序列，我们对该真菌的 MAT 基因座结构进行了研究。结果表明，栓皮栎长喙壳菌是异宗配合（自交不育）的，具有完整且功能明显的 MAT 基因的拷贝，其中包含存在于不同分离株中的α-1 和 HMG 结构域。除了 MAT1-2-1 和 MAT1-1-1 基因外，我们还在 MAT1-1 同型物中发现了 MAT1-1-4 基因，在 MAT1-2 同型物中发现了一个新的 MAT1-2-5 基因。重要的是，在所研究的种群中，两种同型物的出现频率与预期的有性繁殖种群中的 1:1 比例没有显著差异。尽管从未观察到有性状态，但研究结果强烈表明，栓皮栎长喙壳菌具有隐生的异宗配合有性循环。
