Department of Plant Pathology and Plant-Microbe Biology, Cornell University, Geneva, NY 14456, USA.
Phytopathology. 2011 Jul;101(7):839-46. doi: 10.1094/PHYTO-11-10-0295.
Asexual sporulation (conidiation) is coordinately regulated in the grape powdery mildew pathogen Erysiphe necator but nothing is known about its genetic regulation. We hypothesized that genes required for conidiation in other fungi would be upregulated at conidiophore initiation or full conidiation (relative to preconidiation vegetative growth and development of mature ascocarps), and that the obligate biotrophic lifestyle of E. necator would necessitate some novel gene regulation. cDNA amplified fragment length polymorphism analysis with 45 selective primer combinations produced ≈1,600 transcript-derived fragments (TDFs), of which 620 (39%) showed differential expression. TDF sequences were annotated using BLAST analysis of GenBank and of a reference transcriptome for E. necator developed by 454-FLX pyrosequencing of a normalized cDNA library. One-fourth of the differentially expressed, annotated sequences had similarity to fungal genes of unknown function. The remaining genes had annotated function in metabolism, signaling, transcription, transport, and protein fate. As expected, a portion of orthologs known in other fungi to be involved in developmental regulation was upregulated immediately prior to or during conidiation; particularly noteworthy were several genes associated with the light-dependent VeA regulatory system, G-protein signaling (Pth11 and a kelch repeat), and nuclear transport (importin-β and Ran). This work represents the first investigation into differential gene expression during morphogenesis in E. necator and identifies candidate genes and hypotheses for characterization in powdery mildews. Our results indicate that, although control of conidiation in powdery mildews may share some basic elements with established systems, there are significant points of divergence as well, perhaps due, in part, to the obligate biotrophic lifestyle of powdery mildews.
无性孢子形成（分生孢子形成）在葡萄白粉病病原体 Erysiphe necator 中受到协调调控，但对其遗传调控知之甚少。我们假设，其他真菌中分生孢子形成所需的基因在分生孢子梗起始或完全分生孢子形成时（相对于分生孢子前营养生长和成熟子囊果的发育）会被上调，而 E. necator 的专性生物营养生活方式将需要一些新的基因调控。使用 45 个选择性引物组合进行 cDNA 扩增片段长度多态性分析，产生了约 1600 个转录衍生片段（TDF），其中 620 个（39%）表现出差异表达。使用 BLAST 分析 GenBank 和 E. necator 的参考转录组对 TDF 序列进行注释，该转录组是通过对归一化 cDNA 文库进行 454-FLX 焦磷酸测序开发的。差异表达、注释序列的四分之一与真菌中未知功能的基因具有相似性。其余基因在代谢、信号转导、转录、运输和蛋白质命运方面具有注释功能。不出所料，在其他真菌中已知参与发育调控的一部分同源基因在分生孢子形成之前或期间被上调；特别值得注意的是几个与光依赖性 VeA 调节系统、G 蛋白信号（Pth11 和一个 kelch 重复）和核转运（importin-β 和 Ran）相关的基因。这项工作代表了对白粉病病原体 E. necator 形态发生过程中差异基因表达的首次研究，并确定了候选基因和假说，以供在白粉病中进行表征。我们的结果表明，尽管白粉病中的分生孢子形成控制可能与已建立的系统共享一些基本要素，但也存在显著的分歧，这可能部分归因于白粉病的专性生物营养生活方式。
