Institute for Plant Biochemistry, Heinrich-Heine-Universität, Universitätsstrasse 1, D-40225 Düsseldorf, Germany.
Mol Plant. 2012 Nov;5(6):1227-41. doi: 10.1093/mp/sss045. Epub 2012 Apr 24.
A series of reticulated Arabidopsis thaliana mutants were previously described. All mutants show a reticulate leaf pattern, namely green veins on a pale leaf lamina. They have an aberrant mesophyll structure but an intact layer of bundle sheath cells around the veins. Here, we unravel the function of the previously described reticulated EMS-mutant dov1 (differential development of vascular associated cells 1). By positional cloning, we identified the mutated gene, which encodes glutamine phosphoribosyl pyrophosphate aminotransferase 2 (ATase2), an enzyme catalyzing the first step of purine nucleotide biosynthesis. dov1 is allelic to the previously characterized cia1-2 mutant that was isolated in a screen for mutants with impaired chloroplast protein import. We show that purine-derived total cytokinins are lowered in dov1 and crosses with phytohormone reporter lines revealed differential reporter activity patterns in dov1. Metabolite profiling unraveled that amino acids that are involved in purine biosynthesis are increased in dov1. This study identified the molecular basis of an established mutant line, which has the potential for further investigation of the interaction between metabolism and leaf development.
先前已经描述了一系列网纹拟南芥突变体。所有突变体均表现出网状叶片图案，即在淡色叶片上有绿色叶脉。它们具有异常的叶肉结构，但叶脉周围仍有完整的一层束鞘细胞。在这里，我们揭示了先前描述的网纹 EMS 突变体 dov1（与血管相关细胞的差异发育 1）的功能。通过定位克隆，我们鉴定了突变基因，该基因编码谷氨酰胺磷酸核糖焦磷酸氨基转移酶 2（ATase2），这是一种催化嘌呤核苷酸生物合成第一步的酶。dov1 与先前在筛选叶绿体蛋白导入缺陷突变体时分离出的 cia1-2 突变体等位。我们表明，dov1 中嘌呤衍生的总细胞分裂素降低，与植物激素报告线的杂交显示 dov1 中的报告活性模式存在差异。代谢物分析表明，参与嘌呤生物合成的氨基酸在 dov1 中增加。这项研究确定了一个已建立的突变体系的分子基础，该突变体系有可能进一步研究代谢和叶片发育之间的相互作用。
