Department of Molecular Biology, Aarhus University, Aarhus C, Denmark.
Plant Cell Rep. 2012 Jan;31(1):187-203. doi: 10.1007/s00299-011-1155-2. Epub 2011 Oct 2.
Sarpo Mira, a potato variety with high resistance against the late blight pathogen Phytophthora infestans, is being used in breeding programs to increase late blight resistance in commercial varieties. Discovering genes that are important for P. infestans resistance will assist in the development of molecular markers for the selection of new resistant cultivars and the use of resistant varieties will reduce the environmental, health and financial costs associated with the use of pesticides. Using complementary DNA amplified fragment length polymorphism analyses, differentially expressed genes involved in the potato-P. infestans interaction were identified in the susceptible Bintje and in the resistant Sarpo Mira potato cultivars. Forty-eight differentially expressed transcript derived fragments (TDFs) were cloned and sequenced. The expression profiles of some of these genes were analyzed in detail using quantitative RT-PCR at seven time points: 1, 4, 17, 24, 30, 41 and 65 hours after inoculation (hai). We found that five transcripts with homologies to pathogenesis/defense-related genes and two TDFs with homology to transcription factors were significantly induced to higher levels in the resistant cultivar at very early stages of the infection (1 hai). Interestingly, most of these genes showed different expression profiles throughout the whole infection process between both cultivars. Particularly during its biotrophic growth phase, P. infestans triggered the down-regulation of infection responsive genes in the susceptible but not in the resistance cultivar. Our results suggest that these newly identified early-induced transcripts may be good candidates for conferring Sarpo Mira's resistance to late blight and they could be useful molecular markers for the selection of new resistant cultivars.
米拉马铃薯（Sarpo Mira）是一种对晚疫病菌（Phytophthora infestans）具有高度抗性的马铃薯品种，目前正在被用于育种计划中，以提高商业品种的晚疫病抗性。发现对晚疫病抗性重要的基因将有助于开发分子标记，用于选择新的抗性品种，而使用抗性品种将降低与使用农药相关的环境、健康和经济成本。本研究使用 cDNA 扩增片段长度多态性分析方法，在易感品种邦杰（Bintje）和抗性品种米拉马铃薯中鉴定了与马铃薯-晚疫病菌互作相关的差异表达基因。克隆和测序了 48 个差异表达的转录衍生片段（TDFs）。使用定量 RT-PCR 在 7 个时间点（接种后 1、4、17、24、30、41 和 65 小时）对其中一些基因的表达谱进行了详细分析。我们发现，有 5 个与致病/防御相关基因同源的转录本和 2 个与转录因子同源的 TDF 在感染的早期（1 hai）阶段，在抗性品种中被高度诱导表达。有趣的是，在整个感染过程中，这些基因在两个品种中的表达模式存在很大差异。特别是在其生物营养生长阶段，晚疫病菌在易感品种中下调了感染响应基因的表达，但在抗性品种中没有。我们的结果表明，这些新鉴定的早期诱导转录本可能是赋予米拉马铃薯对晚疫病抗性的良好候选基因，它们可以作为选择新的抗性品种的有用分子标记。
