Roche D, Temple S J, Sengupta-Gopalan C
Dept. of Agronomy & Horticulture, New Mexico State University, Las Cruces 88003.
Plant Mol Biol. 1993 Sep;22(6):971-83. doi: 10.1007/BF00028970.
We have characterized two sets of cDNA clones representing the glutamine synthetase (GS) mRNA in soybean nodules. Using the 3'-untranslated regions of a representative member of each set, as gene member(s) specific probes, we have shown that one set of the GS genes are expressed in a nodule-specific manner, while the other set is expressed in other tissues, besides the nodules. The nodule-specific GS genes are expressed in a developmentally regulated manner in the nodules, independent of the onset of nitrogen fixation. The other class of GS genes is expressed constitutively in all tissues tested, but its expression level is dramatically enhanced in nodules following onset of N2 fixation. The latter set of genes is also expressed in cotyledons of germinating seedlings in a developmentally regulated manner. Analysis of hybrid select translation products and genomic Southern blots suggests that multiple gene members in each class are expressed in the nodules.
我们已经鉴定了两组代表大豆根瘤中谷氨酰胺合成酶（GS）mRNA的cDNA克隆。利用每组中一个代表性成员的3'非翻译区作为基因成员特异性探针，我们发现一组GS基因以根瘤特异性方式表达，而另一组除根瘤外还在其他组织中表达。根瘤特异性GS基因在根瘤中以发育调控的方式表达，与固氮作用的开始无关。另一类GS基因在所有测试组织中组成性表达，但其表达水平在N2固定开始后在根瘤中显著增强。后一组基因也以发育调控的方式在发芽幼苗的子叶中表达。对杂交选择翻译产物和基因组Southern印迹的分析表明，每组中的多个基因成员在根瘤中表达。
