Abstract: RNAs isolated from plants of a rice cultivar inoculated with two different races of the blast fungus were used to construct two cDNA libraries enriched for transcripts differentially expressed in incompatible/compatible interactions through suppression subtractive hybridization (SSH). After differential screening and RT-PCR based confirmation, twenty-five unique cDNA clones showing differentially expressions in incompatible/compatible interactions were sequenced. These cDNA clones were with known functions according to the putative functions of their homologous genes in the database. They might be involved in pathogen response, transcription, protein synthesis and protein fate etc. Expression profilings of the 25 cDNA clones at the early stages after inoculation were also revealed by RT-PCR. All of their expression levels were identical at 0 h of inoculation, followed by inducing or suppressing in the two interactions, indicating that the expression changes of these genes were solely due to different races of the pathogen and the reliability of the selected genes in the present experiment. It is also postulated that in rice-Magnaporthe grisea interactions, the time points and levels of expressions of some defense-related genes might determine the race-specific resistances of the host.

Key words: Magnaporthe grisea, incompatible/compatible host-pathogen interactions, suppression subtractive hybridization, rice

摘要： 以同一水稻品种接种不同小种稻瘟菌，利用抑制消减杂交（SSH）技术构建水稻稻瘟菌非亲和/亲和互作消减cDNA 文库。 经差异筛选、序列分析及RTPCR验证，共获得25个独立的差异表达cDNA克隆。根据与它们同源基因的功能推测，这些cDNA克隆可能参与了对病原菌的防卫反应、转录和蛋白合成与修饰等一些重要的生物学过程。通过RTPCR检测了差异表达基因在非亲和/亲和互作早期的表达谱，所有被检测基因在非亲和/亲和互作零点的表达水平均相同，而在接种后的其他时间点，它们的表达在互作反应中或被诱导或被抑制，说明这些表达的变化仅仅与接种的不同小种有关，肯定了所分离到的基因及其表达变化的可靠性。受不同小种病原菌侵染后，由于一些参与防卫反应的基因被诱导或被抑制的程度和持续时间的不同可能导致水稻小种特异的抗性。

关键词: 稻瘟病, 非亲和/亲和互作, 抑制消减杂交, 水稻