Marshall J S, Stubbs J D, Taylor W C
Commonwealth Scientific and Industrial Research Organization Division of Plant Industry, Canberra, Australia.
Plant Physiol. 1996 Aug;111(4):1251-61. doi: 10.1104/pp.111.4.1251.
To gain an understanding of the molecular events underlying the evolution of C4 photosynthesis, we have undertaken as detailed study of the NADP-malic enzyme gene family in C4 and C3 species of Flaveria. Three genomic clones form the C4 species Flaveria bidentis were characterized and found to encode two highly similar chloroplastic forms of NADP-malic enzyme, termed ME1 and ME2. Genomic southern blotting with gene-specific probes showed that both Me1 and Me2 are found in Flaveria trinervia (C4) and Flaveria pringlei (C3) as well as in F. bidentis. Northern blots demonstrated that Me1 expression in leaves parallels the degree of C4 photosynthesis in seven Flaveria species. Furthermore, whereas Me2 was expressed at a low level in both roots and leaves of F. bidentis, Me1 expression was seen only in leaves and was light-regulated. We discuss these results in the context of the evolution of C4 photosynthesis in Flaveria.
为了了解C4光合作用进化背后的分子事件，我们对黄顶菊属C4和C3物种中的NADP - 苹果酸酶基因家族进行了详细研究。对来自C4物种二齿黄顶菊的三个基因组克隆进行了表征，发现它们编码两种高度相似的叶绿体形式的NADP - 苹果酸酶，分别称为ME1和ME2。用基因特异性探针进行的基因组Southern印迹分析表明，Me1和Me2在三脉黄顶菊（C4）、普氏黄顶菊（C3）以及二齿黄顶菊中均有发现。Northern印迹显示，Me1在叶片中的表达与七个黄顶菊物种中C4光合作用的程度平行。此外，虽然Me2在二齿黄顶菊的根和叶中均低水平表达，但Me1仅在叶片中表达且受光调节。我们在黄顶菊属C4光合作用进化的背景下讨论了这些结果。
