Enhanced expression of antifreeze protein genes drives the development of freeze tolerance in an Antarctica isolate of Chlorella vulgaris  

作　　者：Huiying Li Xiaoxiang Liu Yali Wang Hanhua Hu Xudong Xu 

机构地区：[1]State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China

出　　处：《Progress in Natural Science:Materials International》2009年第9期1059-1062,共4页自然科学进展·国际材料（英文版）

基　　金：supported by the Key Project (KSCX2-SW-332) of the Knowledge Innovation Program of the Chinese Academy of Sciences;the National Natural Science Foundation of China (No. 40606004);the National Key Basic Research Project of China(2004CB719605)

摘　　要：In adaptation to new environments, organisms may accumulate mutations within encoding sequences to modify protein characteristics or acquire mutations within regulatory sequences to alter gene expression levels. With the development of antifreeze capability as the example, this study presents the evidence that change in gene expression level is probably the most important mechanism for adaptive evolution in a green alga Chlorella vulgaris. C. vulgaris NJ-7, an isolate from Antarctica, possesses an 18S rRNA sequence identical to that of a temperate isolate, SAG211-1 1b/UTEX259, but shows much higher freeze tolerance than the later isolate. The chromosomal DNA/cDNA of four antifreeze genes, namely hiC6, hiC12, rpllOa and hsp70, from the two isolates of C. vulgaris were cloned and sequenced, and very few variations of deduced amino acid sequences were found. In contrast, the transcription of hiC6, hiC12 and rpllOa was greatly intensified in N J-7 compared to that in UTEX259, which is correlated to the significantly enhanced freeze tolerance of the Antarctica isolate.In adaptation to new environments, organisms may accumulate mutations within encoding sequences to modify protein characteristics or acquire mutations within regulatory sequences to alter gene expression levels. With the development of antifreeze capability as the example, this study presents the evidence that change in gene expression level is probably the most important mechanism for adaptive evolution in a green alga Chlorella vulgaris. C. vulgaris NJ-7, an isolate from Antarctica, possesses an 18S rRNA sequence identical to that of a temperate isolate, SAG211-11b/UTEX259, but shows much higher freeze tolerance than the later isolate. The chromosomal DNA/cDNA of four antifreeze genes, namely hiC6, hiC12, rpl10a and hsp70, from the two isolates of C. vulgaris were cloned and sequenced, and very few variations of deduced amino acid sequences were found. In contrast, the transcription of hiC6, hiC12 and rpl10a was greatly intensified in NJ-7 compared to that in UTEX259, which is correlated to the significantly enhanced freeze tolerance of the Antarctica isolate.

关 键 词：Chlorella vulgaris Antarctica isolate Temperate isolate Freeze tolerance Gene expression 

分 类 号：Q949.217[生物学—植物学] S641.203.2[农业科学—蔬菜学]