Characterization of Three Homoeologous cDNAs Encoding Chloroplast-targeted Aminolevulinic Acid Dehydratase in Common Wheat  

作　　者：Yu Takenouchi Haruka Nakajima Kengo Kanamaru Shigeo Takumi 

机构地区：[1]Laboratory of Plant Genetics, Graduate School of Agricultural Science, Kobe University, Kobe 657-8501, Japan [2]Laboratory of Biological Chemistry, Graduate School of Agricultural Science, Kobe University, Kobe 657-8501, Japan

出　　处：《Journal of Integrative Plant Biology》2011年第12期942-950,共9页植物学报（英文版）

基　　金：supported by grants from the Ministry of Education, Culture, Sports, Science and Technology of Japan (Grant-in-Aid for Scientific Research (B) No. 21380005;Grant-in-Aid for Challenging Exploratory Research No. 23658010) to Shigeo Takumi;partially supported by Special Coordination Funds for Promoting Science and Technology, Creation of Innovation Centers for Advanced Interdisciplinary Research Areas (Innovative Bioproduction Kobe), MEXT, Japan.

摘　　要：In the tetrapyrrole biosynthetic pathway of higher plants, 5-aminolevulinic acid （ALA） is metabolized by ALA dehydratase （ALAD）. Here, we isolated ALAD1 cDNA from common wheat （Triticum aestivum L.） and its diploid progenitors, and produced transgenic tobacco plants expressing the wheat ALAD1 gene. The ALAD1 genes were highly conserved among wheat relatives, and three homoeologous loci of wheat ALAD1 （TaALAD1） were equally transcribed in common wheat. A transient expression assay of a TaALAD1-GFP （green fluorescent protein） fusion protein suggested that TaALAD1 is localized in chloroplasts. Overexpression of TaALAD1 in transgenic tobacco resulted in a significant increase in ALAD activity in leaves. Moreover, the transgenic tobacco showed vigorous growth and increased survival rate on medium containing ALA at herbicidal concentrations. These results indicate that wheat ALAD1 has catalytic activity in metabolizing ALA in plastids, and that ectopic expression of TaALAD1 in transgenic plants increases their tolerance to ALA application at high concentrations.In the tetrapyrrole biosynthetic pathway of higher plants, 5-aminolevulinic acid （ALA） is metabolized by ALA dehydratase （ALAD）. Here, we isolated ALAD1 cDNA from common wheat （Triticum aestivum L.） and its diploid progenitors, and produced transgenic tobacco plants expressing the wheat ALAD1 gene. The ALAD1 genes were highly conserved among wheat relatives, and three homoeologous loci of wheat ALAD1 （TaALAD1） were equally transcribed in common wheat. A transient expression assay of a TaALAD1-GFP （green fluorescent protein） fusion protein suggested that TaALAD1 is localized in chloroplasts. Overexpression of TaALAD1 in transgenic tobacco resulted in a significant increase in ALAD activity in leaves. Moreover, the transgenic tobacco showed vigorous growth and increased survival rate on medium containing ALA at herbicidal concentrations. These results indicate that wheat ALAD1 has catalytic activity in metabolizing ALA in plastids, and that ectopic expression of TaALAD1 in transgenic plants increases their tolerance to ALA application at high concentrations.

关 键 词：5-aminolevulinic acid chloroplast targeting herbicide resistance transgenic tobacco Triticum aestivum 5-aminolevulinic acid dehydratase transcriptional control 

分 类 号：S512.1[农业科学—作物学]