以对小麦白粉病菌免疫的小黑麦异多附加系Ｍ１７（１Ｒ“６Ｒ”）为材料，一组接种小麦白粉病菌，另一组不接种．分别提取两组叶片的总ＲＮＡ，经磁珠法分离出ｐｏｌｙ（Ａ＋）ＲＮＡ，以Ｏｌｉｇｏ（ｄＴ）为引物，经反转录合成ｃＤＮＡ．将接种组双链ｃＤＮＡ克隆进λｇｔ１０载体，得到一个含９．８×１０４个重组噬菌体的ｃＤＮＡ文库．两组ｃＤＮＡ双链经切口平移法制成总ｃＤＮＡ探针，分别与ｃＤＮＡ文库杂交，通过差别筛选的方法，找到了６个与小麦白粉病抗性有关的ｃＤＮＡ克隆． One is inoculated with powdery mildew of wheat (Triticum aestivum), and the other is not inoculated with M17 (1R “6R”). The total RNA was extracted from the leaves of two groups. The poly (A +) RNA was isolated by magnetic beads method and the cDNA was synthesized by reverse transcription using Oligo (dT) as primer. The seeding group double-stranded cDNA was cloned into the λgt10 vector to obtain a cDNA library containing 9.8 × 104 recombinant phage. Two sets of cDNA duplexes were cut by pan method to generate total cDNA probes. The cDNAs were hybridized with cDNA library respectively. Six cDNA clones related to powdery mildew resistance were found by differential screening.