Identification of the Arabidopsis CHL3 gene as the nitrate reductase structural gene NIA2.
Identification of the Arabidopsis CHL3 gene as the nitrate reductase structural gene NIA2.
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DOI：
10.1105/tpc.3.5.461
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发表时间：
1991-05
期刊：
影响因子：
--
通讯作者：
J. Wilkinson;N. Crawford
中科院分区：
文献类型：
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作者：
J. Wilkinson;N. Crawford
氯酸盐，硝酸盐的氯类似物，是一种除草剂，已被用于选择在硝酸盐同化过程中受损的突变体。在拟南芥中，八个不同基因座中的任何一个突变都会赋予氯酸盐抗性。在这些位点的基因的分子身份是未知的，然而，这些位点之一-chl 3-地图非常接近硝酸还原酶结构基因NIA 2。通过对γ射线照射产生的新的抗氯酸盐突变体的分离、表征和遗传分析，我们已经能够证明CHL 3基因和NIA 2基因是相同的。三个新的氯酸盐抗性突变体被确定为具有整个NIA 2基因的缺失。这些nia 2无效突变体是可行的，并且在植物的叶子中仍然保留10%的野生型硝酸还原酶活性。所有三个缺失突变被发现是chl 3的新等位基因。通过农杆菌介导的转化将NIA 2基因引入这些chl 3突变体中，部分地补充了它们的突变体表型。从这些数据中，我们得出结论，拟南芥至少有两个功能性硝酸还原酶基因和NIA 2基因产物占大多数的叶硝酸还原酶活性和氯酸盐敏感性的拟南芥植物。
Chlorate, the chlorine analog of nitrate, is a herbicide that has been used to select mutants impaired in the process of nitrate assimilation. In Arabidopsis thaliana, mutations at any one of eight distinct loci confer resistance to chlorate. The molecular identities of the genes at these loci are not known; however, one of these loci--chl3--maps very near the nitrate reductase structural gene NIA2. Through the isolation, characterization, and genetic analysis of new chlorate-resistant mutants generated by gamma irradiation, we have been able to demonstrate that the CHL3 gene and the NIA2 gene are identical. Three new chlorate-resistant mutants were identified that had deletions of the entire NIA2 gene. These nia2 null mutants were viable and still retained 10% of wild-type nitrate reductase activity in the leaves of the plants. All three deletion mutations were found to be new alleles of chl3. Introduction of the NIA2 gene back into these chl3 mutants by Agrobacterium-mediated transformation partially complemented their mutant phenotype. From these data, we conclude that Arabidopsis has at least two functional nitrate reductase genes and that the NIA2 gene product accounts for the majority of the leaf nitrate reductase activity and chlorate sensitivity of Arabidopsis plants.