Characterization of three homoeologous cDNAs encoding chloroplast-targeted aminolevulinic acid dehydratase in common wheat
Characterization of three homoeologous cDNAs encoding chloroplast-targeted aminolevulinic acid dehydratase in common wheat
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普通小麦叶绿体靶向氨基乙酰丙酸脱水酶的三种同源 cDNA 的表征
DOI：
10.1111/j.1744-7909.2011.01083.x
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发表时间：
2011
期刊：
影响因子：
--
通讯作者：
他
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文献类型：
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作者：
Takenouchi;Y.;他
在高等植物的四吡咯生物合成途径中，5-氨基乙酰丙酸（ALA）由ALA脱氢酶（ALAD）代谢。本研究从普通小麦（Triticum aestivumL.）及其二倍体祖先，并产生了表达小麦ALAD1基因的转基因烟草植株。ALAD1基因在小麦近缘种中高度保守，并且小麦ALAD1的3个同源位点（TaALAD1）在普通小麦中转录一致。TaALAD1-GFP（绿色荧光蛋白）融合蛋白的瞬时表达测定表明TaALAD1定位于叶绿体中。在转基因烟草中过量表达TaALAD1导致叶片ALAD活性显著增加。此外，转基因烟草在含有除草剂浓度的ALA的培养基上表现出旺盛的生长和增加的存活率。这些结果表明小麦ALAD1在质体中具有催化ALA代谢的活性，并且TaALAD1在转基因植物中的异位表达增加了它们对高浓度ALA施用的耐受性。
In the tetrapyrrole biosynthetic pathway of higher plants, 5‐aminolevulinic acid (ALA) is metabolized by ALA dehydratase (ALAD). Here, we isolatedALAD1cDNA from common wheat (Triticum aestivumL.) and its diploid progenitors, and produced transgenic tobacco plants expressing the wheatALAD1gene. TheALAD1genes were highly conserved among wheat relatives, and three homoeologous loci of wheatALAD1(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 ofTaALAD1in 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 ofTaALAD1in transgenic plants increases their tolerance to ALA application at high concentrations.