First, second, third, fourth, an fifth authors: Department of Soil, Plant and Food Sciences, University of Bari Aldo Moro, via Amendola 165/A, 70126 Bari, Italy; and second, fourth, and firth authors: SELGE Network of Public Research Laboratories, via Amendola 165/A, 70126 Bari, Italy.
Phytopathology. 2018 Nov;108(11):1315-1325. doi: 10.1094/PHYTO-03-18-0074-R. Epub 2018 Oct 2.
Monilinia fructicola, M. laxa, and M. fructigena are the most important pathogens responsible for brown rot disease of stone and pome fruits. Information on their mating system and sexual behavior is scant. A mating-type-specific PCR-based assay was developed and applied to 155 Monilinia isolates from 10 countries and 10 different host plants. We showed that single isolates carry only one of two opposite idiomorphs at the MAT1 locus consistent with a heterothallic mating system for all three species. MAT1-1 and MAT1-2 mating types were detected in similar proportions in samples of isolates of each species and hence there do not appear to be genetic obstacles to the occurrence of sexual reproduction in their populations. Inter simple sequence repeat markers suggested that asexual reproduction is prevalent, but that sexual recombination occurs in M. fructicola populations in Italy. The genetic architectures of the MAT1 loci of the three pathogens were analyzed. MAT1-1 and MAT1-2 idiomorphs are flanked upstream and downstream by the APN2 and SLA2 genes and resemble those of Botrytis cinerea and other heterothallic fungi in the family Sclerotiniaceae. Each idiomorph contains a specific couple of genes, MAT1-1-1 (with alpha-box domain) and MAT1-1-5 in MAT1-1, and MAT1-2-1 (with HMG-box domain) and MAT1-2-10 in MAT1-2. Small gene fragments (dMAT1-1-1 and dMAT1-2-1) from the opposite idiomorph were detected close to their flanking regions. Constitutive expression of the four MAT1 genes during vegetative growth was ascertained by transcriptomic analysis (RNA-Seq). Antisense transcription of the MAT1-1-1 and MAT1-2-1 genes and intergenic transcribed regions of the MAT1 locus were detected. These results represent new insights into the mating systems of these three economically-important pathogens which could contribute to improve the knowledge on their population biology.
桑红赤霉、M. laxa 和 M. fructigena 是导致核果和仁果褐腐病的最重要病原菌。有关它们交配系统和性行为的信息很少。我们开发了一种基于交配型特异性 PCR 的检测方法，并应用于来自 10 个国家和 10 种不同宿主植物的 155 个 Monilinia 分离物。结果表明，单个分离物在 MAT1 基因座上仅携带两种相反的等位基因之一，这与三种物种的异宗交配系统一致。在每个物种的分离物样本中均检测到 MAT1-1 和 MAT1-2 交配型，因此其种群中似乎不存在发生有性生殖的遗传障碍。简单重复序列间标记表明，无性繁殖普遍存在，但在意大利的 M. fructicola 种群中存在有性重组。分析了三个病原菌 MAT1 基因座的遗传结构。MAT1-1 和 MAT1-2 等位基因上游和下游分别由 APN2 和 SLA2 基因侧翼，与 Botrytis cinerea 和其他 Sclerotiniaceae 家族的异宗真菌相似。每个等位基因包含一对特定的基因，MAT1-1-1（带有α盒结构域）和 MAT1-1-5 在 MAT1-1 中，以及 MAT1-2-1（带有 HMG 盒结构域）和 MAT1-2-10 在 MAT1-2 中。在其侧翼区域附近检测到来自相反等位基因的小基因片段（dMAT1-1-1 和 dMAT1-2-1）。通过转录组分析（RNA-Seq）确定了四个 MAT1 基因在营养生长过程中的组成型表达。检测到 MAT1-1-1 和 MAT1-2-1 基因的反义转录和 MAT1 基因座的基因间转录区。这些结果为这三种具有经济重要性的病原菌的交配系统提供了新的见解，有助于提高对其种群生物学的认识。
