The promoter for C4-type mitochondrial aspartate aminotransferase does not direct bundle sheath-specific expression in transgenic rice plants
The promoter for C4-type mitochondrial aspartate aminotransferase does not direct bundle sheath-specific expression in transgenic rice plants
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DOI：
10.1093/pcp/pci077
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发表时间：
2005-05-01
影响因子：
4.9
通讯作者：
Tajima, S
中科院分区：
文献类型：
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作者：
Nomura, M;Higuchi, T;Tajima, S
对于NAD-苹果酸酶（NAD-ME）-型C-4光合作用，涉及两种类型的天冬氨酸转氨酶（AAT）。我们检测了转基因水稻植株中黍线粒体Aat基因（PmAat）和黍胞质Aat基因（PcAat）的表达模式，它们分别在维管束鞘细胞（BSC）和叶肉细胞（MC）中特异性表达。在PcAat启动子控制下的β-葡萄糖醛酸酶（GUS）报告基因的表达在转基因水稻植株中以器官优先和光依赖的方式进行调节。然而，PmAat启动子驱动GUS在我们测试的所有器官中的表达而没有光依赖性，并且在引入完整PmAat基因的转基因水稻中也观察到这种非优先表达模式。水稻线粒体Aat（RmAat 1）基因在所有器官中的表达均不依赖于光，而水稻胞质Aat（RcAat 1）基因的表达则表现出器官偏好性和光依赖性。综合这些结果，我们可以概括出，BSC特异性或光依赖性的线粒体Aat表达的调节系统在粟粒青霉（C-4）和水稻（C-3）之间不共享，并且导入水稻的C-4基因的表达模拟了它们在水稻中的对应基因的表达。
For NAD-malic enzyme (NAD-ME)-type C-4 photosynthesis, two types of aspartate aminotransferase (AAT) are involved. We examined the expression pattern of the Panicum miliaceum mitochondrial Aat gene (PmAat) and P. miliaceum cytosolic Aat gene (PcAat) in transgenic rice plants, which were specifically expressed in bundle sheath cells (BSCs) and mesophyll cells (MCs), respectively. Expression of a beta-glucuronidase (GUS) reporter gene under the control of the PcAat promoter was regulated in an organ-preferential and light-dependent manner in the transgenic rice plants. However, the PmAat promoter drove the GUS expression in all organs we tested without light dependency, and this non-preferential expression pattern was also observed in transgenic rice with introduction of the intact PmAat gene. The expression patterns of the rice counterpart Aat genes to PmAat or PcAat showed that the rice mitochondrial Aat (RmAat1) gene was expressed in all organs tested in a light-independent manner, while expression of the rice cytosolic Aat (RcAat1) gene showed an organ-preferential and light-dependent pattern. Taking these results together, we can generalize that the regulatory system of BSC-specific or light-dependent expression of mitochondrial Aat is not shared between P. miliaceum (C-4) and rice (C-3) and that the expression of the C-4 genes introduced into rice mimics that of their counterpart genes in rice.