利用SSH 技术鉴定黄瓜抗霜霉病相关基因

采用SSH 技术对黄瓜抗霜霉病自交系M801-3-1 侵染霜霉病菌前后的差异表达基因进行了研究。利用 SSH 技术构建抗病黄瓜材料接种霜霉病菌和未接种差异表达的差减cDNA 文库。经反向Northern blot 杂交检测，共得到48 个阳性克隆。利用分子生物学软件对测序后的序列进行质量检测和聚类、拼接，共得到 14 个UniESTs，其中包括8 个singletons 和6 个contigs。通过SSH-EST 代表基因功能的分析，说明抗氧化胁迫能力和叶绿体的重建和保护机制对抗病品种抗病有重要作用。同时，提出SSH-EST 代表的clpb、HSP70、HSP22 和肽脯氨酰顺反异构酶还可能参与了R 基因介导的防御反应，smHSP 有可能就是R 蛋白的“保卫靶”，负责监测细胞内的异常，这一发现为揭示活性氧机制和R 基因介导的防卫机制之间的关系提供了关键证据。

Using SSH Technology to Identify Relevant Genes Resistant to Cucumber Downy Mildew

Adopting SSH technology，this paper studied on the difference expressive genes of downy
mildew resistant cucumber inbred line‘ M801-3-1’ before and after the infection of downy mildew．Diseaseresistant
cucumber material vaccinated downy mildew and unvaccinated cDNA library was constructed using
SSH technology．Forty-eight positive clones were obtained by reverse Northern blot hybridization detection，
and 14 UniESTs were obtained including 8 singletons and 6 contigs via molecular biology software．The
SSH-EST genes function analysis indicated that oxidative stress resistance and chloroplast reconstruction
and protection mechanisms had very important role on disease resistance．At the same time，the paper
put forward that Clpb，HSP70，HSP22 and peptidyl-prolyl cis-trans isomerase might be involved in the R
gene-mediated defense reaction，and smHSP might be the‘ defending target’ of R protein，responsible for
monitoring intracellular exception．This study has provided a key evidence for revealing the relations between
active oxygen mechanism and R gene mediate protection mechanism．