Department of Plant Pathology, Washington State University, Pullman, 99164-6430, USA.
BMC Genomics. 2009 Dec 23;10:626. doi: 10.1186/1471-2164-10-626.
Stripe rust, caused by Puccinia striiformis f. sp. tritici (Pst), is one of the most destructive diseases of wheat (Triticum aestivum L.) worldwide. In spite of its agricultural importance, the genomics and genetics of the pathogen are poorly characterized. Pst transcripts from urediniospores and germinated urediniospores have been examined previously, but little is known about genes expressed during host infection. Some genes involved in virulence in other rust fungi have been found to be specifically expressed in haustoria. Therefore, the objective of this study was to generate a cDNA library to characterize genes expressed in haustoria of Pst.
A total of 5,126 EST sequences of high quality were generated from haustoria of Pst, from which 287 contigs and 847 singletons were derived. Approximately 10% and 26% of the 1,134 unique sequences were homologous to proteins with known functions and hypothetical proteins, respectively. The remaining 64% of the unique sequences had no significant similarities in GenBank. Fifteen genes were predicted to be proteins secreted from Pst haustoria. Analysis of ten genes, including six secreted protein genes, using quantitative RT-PCR revealed changes in transcript levels in different developmental and infection stages of the pathogen.
The haustorial cDNA library was useful in identifying genes of the stripe rust fungus expressed during the infection process. From the library, we identified 15 genes encoding putative secreted proteins and six genes induced during the infection process. These genes are candidates for further studies to determine their functions in wheat-Pst interactions.
条锈病由条形柄锈菌小麦专化型（Puccinia striiformis f. sp. tritici，Pst）引起，是全球范围内小麦（Triticum aestivum L.）最具破坏性的病害之一。尽管其具有农业重要性，但该病原体的基因组学和遗传学特征尚未得到充分描述。此前已经研究了来自锈菌孢子和萌发锈菌孢子的 Pst 转录本，但对宿主感染过程中表达的基因知之甚少。在其他锈菌中，一些与毒性有关的基因已被发现特异性表达在吸器中。因此，本研究的目的是构建一个 cDNA 文库，以鉴定 Pst 吸器中表达的基因。
从 Pst 的吸器中生成了 5126 条高质量的 EST 序列，从中衍生出 287 个连续序列和 847 个单序列。约 1134 个独特序列中的 10%和 26%分别与具有已知功能和假设蛋白的蛋白同源，其余 64%的独特序列在 GenBank 中没有显著相似性。预测 15 个基因是从 Pst 吸器分泌的蛋白。使用定量 RT-PCR 对包括 6 个分泌蛋白基因在内的 10 个基因进行分析，结果显示在病原体不同发育和感染阶段的转录水平发生了变化。
吸器 cDNA 文库可用于鉴定条锈菌在感染过程中表达的基因。从文库中，我们鉴定了 15 个编码假定分泌蛋白的基因和 6 个在感染过程中诱导的基因。这些基因是进一步研究其在小麦-条锈菌互作中的功能的候选基因。
