厚藤cDNA文库的构建和重金属镉耐受相关基因的筛选

厚藤（Ipomoea pes-caprae（L.） Sweet）是一种具有重要生态、观赏及药用价值的沙滩植物，对重金属镉（Cd）具有一定的富集能力，可作为Cd污染滨海地区的修复植物进行引种栽植和利用。本研究通过Gateway技术构建厚藤的cDNA文库，将该文库质粒转化酵母对Cd敏感的突变株ycf1△，采用全长cDNA过表达基因捕获系统（FOX）筛选厚藤重金属Cd胁迫耐受相关基因，并采用酵母互补实验进行基因的功能验证。本研究获得了2个能够恢复ycf1△对Cd敏感表型的重组质粒，经测序分析，该重组质粒包含的cDNA全长序列分别对应厚藤植物螯合肽合成酶基因（phytochelatin synthase）和金属硫蛋白基因（metallothionein），分别将其命名为IpPCS和IpMT，通过功能分析，初步认定该基因为编码Cd耐受和解毒相关蛋白的候选基因。

Construction of a cDNA library of Ipomoea pes-caprae L.and screening for cadmium tolerant genes

Ipomoea pes-caprae(L.) Sweet,as a coastal beach halophyte with great ecological,ornamental,and medicinal value,has the capacity to enrich heavy metal cadmium and can be used in phytoremediation.We constructed a cDNA library for expression in yeast with tissues of Ipomoea pes-caprae by gateway technology,and then introduced the library plasmids into cadmium-sensitive yeast mutant strain,ycf1△,and screened the library through the FOX gene hunting system based on functional screening in yeast.We obtained two full-length cDNAs of Ipomoea pes-caprae,which could enhance the Cd tolerance of ycf1△.Sequence analyses indicated that these two cDNAs encoded phytochelatin synthase (IpPCS) and metallothionein (IpMT).This research lays a good foundation for further clarifying the molecular mechanism of plants responding to cadmium,and provides a reference cDNA library for functional screening to clone other stress-related genes in Ipomoea pes-caprae.