Department of Plant Pathology and Plant-Microbe Biology, Cornell University, Ithaca, NY 14853, USA.
Fungal Genet Biol. 2011 Jul;48(7):704-13. doi: 10.1016/j.fgb.2011.04.004. Epub 2011 Apr 15.
In ascomycetes, mating compatibility is regulated by the mating-type locus, MAT1. The objectives of this study were to identify and sequence genes at the MAT1 locus in the grape powdery mildew fungus, Erysiphe necator, to develop a PCR-based marker for determining mating type in E. necator, and to develop degenerate primers for amplification by PCR of conserved regions of mating-type idiomorphs in other powdery mildew fungi. We identified MAT1-2-1 of the MAT1-2 idiomorph in E. necator based on the homologous sequence in the genome of Blumeria graminis f. sp. hordei and we found MAT1-1-1 and MAT1-1-3 of the MAT1-1 idiomorph from transcriptome sequences of E. necator. We developed and applied a reliable PCR-based multiplex marker to confirm that genotype correlated with mating phenotype, which was determined by pairing with mating-type tester isolates. Additionally, we used the marker to genotype populations of E. necator from different Vitis spp. from throughout the USA. We found both mating types were present in all populations and mating-type ratios did not deviate from 1:1. The mating-type genes in E. necator are similar to those of other Leotiomycetes; however, the structure of the MAT1 locus in E. necator, like the MAT1-2 idiomorph of B. graminis, is markedly different from other ascomycetes in that it is greatly expanded and may contain a large amount of repetitive DNA. As a result, we were unable to amplify and sequence either idiomorph in its entirety. We designed degenerate primers that amplify conserved regions of MAT1-1 and MAT1-2 in E. necator, Podosphaera xanthii, Microsphaera syringae, and B. graminis, representing the major clades of the Erysiphales. These degenerate primers or sequences obtained in this study from these species can be used to identify and sequence MAT1 genes or design mating-type markers in other powdery mildew fungi as well.
在子囊菌中，交配相容性由交配型基因座 MAT1 调控。本研究的目的是鉴定和测序葡萄白粉菌 Erysiphe necator 中 MAT1 基因座的基因，开发用于确定 E. necator 交配型的基于 PCR 的标记，并开发用于扩增其他白粉菌交配型异型体保守区的简并引物。我们根据禾柄锈菌 f. sp. hordei 基因组中的同源序列，鉴定了 E. necator 中 MAT1-2-1 的 MAT1-2 异型体，并且从 E. necator 的转录组序列中发现了 MAT1-1-1 和 MAT1-1-3 的 MAT1-1 异型体。我们开发并应用了一种可靠的基于 PCR 的多重标记来确认基因型与交配表型相关，这是通过与交配型测试分离株配对来确定的。此外，我们还使用该标记对来自美国各地不同 Vitis spp 的 E. necator 种群进行了基因分型。我们发现所有种群中都存在两种交配型，并且交配型比例没有偏离 1:1。E. necator 的交配型基因与其他 Leotiomycetes 的相似；然而，E. necator 中的 MAT1 基因座结构与禾柄锈菌的 MAT1-2 异型体相似，与其他子囊菌明显不同，因为它大大扩展并且可能含有大量重复 DNA。因此，我们无法完整地扩增和测序任何异型体。我们设计了简并引物，可扩增 E. necator、Podosphaera xanthii、Microsphaera syringae 和禾柄锈菌中 MAT1-1 和 MAT1-2 的保守区，代表 Erysiphales 的主要分支。这些简并引物或从这些物种中获得的序列可用于鉴定和测序其他白粉菌中的 MAT1 基因或设计交配型标记。
