芜菁夜蛾斯氏线虫G26侵染期幼虫cDNA文库的构建及表达序列标签分析

Construction of the cDNA Library from IJs of Steinernema feltiae G26 and Analysis of Expressed Sequence Tags

本研究以芜菁夜蛾斯氏线虫Steinernema feltiae G26的侵染期幼虫为材料，利用SMART（Switching mechanism at 5′end of RNA transcript）技术，构建了其cDNA文库，得到原始文库的库容为3．7×10^8 cfu／mL。随机挑取450个克隆，测序获得386条质量较好的序列，插入片段多在0．3～3kb之间。将EST序列进行同源性比对，EST中有注释信息的占95．92％，无注释信息的4．08％。蛋白功能分析表明所得EST包括核糖体蛋白类，调节因子，信号传导相关基因，代谢酶类等。此全长cDNA文库的构建成功，为阐明侵染期抗逆性幼虫形成与发育机制以及抗逆代谢机理等提供了重要理论依据。

Entomopathogenic nematodes （EPN） is a new type of bio-pesticide which has great potential for controlling many important agricultural pests. The infective juveniles （IJs） play an important role in its commercialization. A full-length cDNA library from IJs of Steinernema feltiae G26 was constructed using SMART techniques. The titer of primary cDNA library was 3.7×10^8 cfu/mL. Sequencing and sequence similarity searches were performed to analyze the profile of expressed sequence tags （ESTs）. 386 qualified sequences were obtained from 450 clones, the insert size ranged from0.3- 3.0 kb. ESTs sequences similarity was compared in non-redundancies database of GenBank. The results showed that 4.08% ESTs had none homology and these which had high homology included ribosomal protein,translation elongation factor, signal transduction gene, metabolize enzyme and so on. Therefore, a cDNA library, of Steinernema feltiae G26 has been successfully consstructed. It provides basic information for understanding the mechanisms on formation, development and persistence of IJs.