Chair of Agronomy and Plant Breeding, Technische Universität München-Weihenstephan, Am Hochanger 2, 85350 Freising, Germany.
Mol Plant Pathol. 2004 May 1;5(3):191-201. doi: 10.1111/j.1364-3703.2004.00221.x.
SUMMARY To gain deeper understanding of the host-pathogen interaction in the system potato-Phytophthora infestans, subtractive hybridization in combination with cDNA array hybridization was used. Leaflets of a moderately resistant and a susceptible potato cultivar were inoculated with P. infestans. The infection of the potato leaves was quantified by real-time quantitative PCR. Using infected and control tissue, two cDNA libraries highly enriched for P. infestans-induced genes were prepared. Within 531 clones randomly picked and sequenced from the libraries, 285 unigenes were found, from which 182 clones were selected for further analysis by cDNA array hybridization. Sixteen hours post inoculation genes were not induced significantly, whereas 72 h post inoculation induction of gene expression was clearly detectable. In both cultivars, 143 genes were induced moderately (>/= two-fold), and 35 of the selected genes appeared to be strongly induced (>/= seven-fold). Among these clones were mainly genes associated with stress and/or defence mechanisms. The strongest gene induction was found in 4-week-old susceptible plants. In the moderately resistant cultivar, transcripts of a number of genes accumulate with plant age; as a result, induction of gene expression upon infection was less pronounced. Down-regulation of three genes was observed in both cultivars, upon infection. Transcript levels of these three genes increased in uninfected plants within 4 weeks of growth. Other differences in defence responses of the two cultivars could be determined and their effects are discussed.
摘要 为了更深入地了解马铃薯-致病疫霉互作系统中的宿主-病原体相互作用，我们采用了消减杂交与 cDNA 微阵列杂交相结合的方法。用致病疫霉接种中度抗病和感病马铃薯品种的叶片。实时定量 PCR 定量测定马铃薯叶片的感染程度。使用感染和对照组织，制备了两个富含致病疫霉诱导基因的 cDNA 文库。从文库中随机挑选并测序的 531 个克隆中，发现了 285 个单基因，其中 182 个克隆通过 cDNA 微阵列杂交进行了进一步分析。接种后 16 小时，基因诱导不明显，而 72 小时后，基因表达的诱导明显可检测到。在两个品种中，有 143 个基因被中度诱导（>/= 两倍），其中 35 个选定的基因似乎被强烈诱导（>/= 七倍）。这些克隆中主要是与应激和/或防御机制相关的基因。在易感的 4 周龄植物中，基因诱导最强。在中度抗病品种中，随着植物年龄的增长，许多基因的转录物积累；因此，感染后基因表达的诱导不那么明显。在两个品种中，都观察到三个基因的下调。在未感染的植物中，这三个基因的转录水平在 4 周的生长过程中增加。还可以确定两个品种防御反应的其他差异，并讨论其影响。
