Bt抗性和敏感棉铃虫幼虫中肠类胰蛋白酶和类胰凝乳蛋白酶基因克隆及半定量测定

Cloning and Relative Quantitative Determination of Trypsin-like Enzyme and Chymotrypsin-like Enzyme Genes in Larval Midgut of Bt Susceptible and Resistant Helicoverpa armigera

克隆了Bt-Cry1Ac抗性和敏感棉铃虫幼虫中肠类胰蛋白酶和类胰凝乳蛋白酶基因,并进行了半定量RT-PCR测定.定量结果显示,类胰蛋白酶和类胰凝乳蛋白酶在不同龄期棉铃虫中肠表达量存在差异,其中在5龄棉铃虫体内转录水平最高,3龄棉铃虫次之,而在4龄棉铃虫中肠内转录水平最低.此外,相同龄期的抗性品系棉铃虫体内的类胰蛋白酶和类胰凝乳蛋白酶转录水平明显高于敏感品系棉铃虫.中肠类胰蛋白酶和类胰凝乳蛋白酶的mRNA表达量的升高,可能与抗性棉铃虫对Bt杀虫蛋白的抗性演化有关.

The trypsin-like enzyme and chymotrypsin-like enzyme genes in larval midgut of Bt susceptible and resistant Helicoverpa armigera （Hubner） strains were cloned in laboratory. The transcription levels of trypsin-like enzyme and chymotrypsin-like enzyme genes were also determined by relative quantitative RT-PCR method. There were differences in the genetic transcription levels of the two enzymes in the midgut at different developmental stages. The transcription level was highest at the 5^th instar stage, and lower at the 3^th instar stage, lowest at the 4^th instar stage. Moreover, the transcription levels of the two enzymes in resistant strains were higher than those in susceptible strains at the same developmental stages. It was concluded that higher transcription levels of the two enzymes in Bt-CrylAc resistant lavae of H. amigera could bring out resistance evolution to Bt insecticidal proteins. Fig 6, Ref 17