棉铃虫幼虫唾液腺cDNA文库的构建及EST分析

棉铃虫Helicoverpa armigera (Hübner)幼虫唾液中的各种酶类及各种生化组分在棉铃虫与植物相互作用及协同进化中起到重要作用； 唾液腺是棉铃虫唾液成分的合成器官。本研究通过构建棉铃虫幼虫唾液腺全长cDNA文库， 测序得到1 502条EST序列， 聚类分析后获得821个unigenes， 为筛选棉铃虫与寄主互作信号因子提供基因信息资源。使用Blast2 GO软件对821个unigenes进行了比对和功能注释， 初步获得棉铃虫幼虫唾液腺中mRNA的构成特征。结果显示， 在棉铃虫唾液腺ESTs文库中， 鉴定得到脂类相关消化酶基因17个， 糖类相关消化酶基因5个， 半胱氨酸蛋白酶基因1个， 丝氨酸蛋白酶基因20个（其中16个为新发现）， 提示唾液腺的主要功能是分泌消化酶进行预消化; 还发现在棉铃虫幼虫唾液腺中存在表皮蛋白、 气味结合蛋白和化学感受蛋白基因。结果为研究棉铃虫预消化系统打下基础。

cDNA library construction and EST analysis of larval salivary glands of Helicoverpa armigera ( Lepidoptera: Noctuidae)

Helicoverpa armigera(Hübner) saliva play important roles in insect-host plant interactions.In this study we constructed a cDNA library of salivary glands of H.armigera larvae where saliva is secreted.We randomly sequenced 1 501 expressed sequence tags(ESTs),and clustering resulted in a total of 821 unigenes.Blast2 GO program was used to do BLASTx,functional annotation and metabolism analysis.Finally,we classified mRNAs in salivary glands of H.armigera larvae.By annotation of these ESTs,genes encoding 17 enzymes for digestion of fat,5 enzymes for digestion of carbohydrates,and 20 serine proteases(of which 16 are newly reported) were identified,suggesting that the function of salivary glands is secreting saliva for predigestion.The cuticle protein,odorant-binding protein and chemosensory protein genes were identified in salivary glands of H.armigera larvae for the first time.The results will lay a foundation for studying predigestion system in H.armigera.