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.