Data from: Loci controlling nitrate reductase activity in maize: ultraviolet-B signaling in aerial tissues increases nitrate reductase activity in leaf and root when responsive alleles are present

Environmental factors, such as ultraviolet-B (UV-B) irradiation, have the ability to affect pathways such as nitrogen metabolism. As fixed nitrogen is the keystone mineral nutrient that controls grain crop yield, any alteration in this cycle can be detrimental to plant productivity. Nitrate reductase enzyme activity is responsible for the reduction of nitrate to nitrite, and nitrate is the major form of nitrogen assimilated in plants. In maize (Zea mays L.) production, nitrate assimilation kinetics are important for both high- and low-input agricultural systems. Nitrate reductase protein activity is controlled by phosphatases and kinases. Nitrate reductase activity is responsive to environmental signals such as light–dark cycles and UV-B radiation, although the regulatory controls are not yet fully understood. We have determined the location of maize genetic factors that control nitrate reductase activity and the extent of contribution of each of these factors, both locally in the leaf tissue and via long-distance signaling loci that affect root nitrate reductase activity upon leaf UV irradiation. In the IBM94 recombinant inbred mapping population, the loci controlling regulation of nitrate reductase activity under UV-B map to different positions than the loci controlling nitrate reductase activity in unexposed plants.

环境因子（如紫外线-B（UV-B）辐照）可影响包括氮代谢在内的多条代谢通路。固定态氮是调控谷类作物产量的关键矿质营养，因此该氮循环的任何扰动均可能对植物生产力造成不利影响。硝酸还原酶（Nitrate reductase）的酶活性负责将硝酸盐还原为亚硝酸盐，而硝酸盐是植物同化氮素的主要存在形式。在玉米（Zea mays L.）栽培中，硝酸盐同化动力学特性对高投入与低投入农业生产体系均具有重要意义。硝酸还原酶的蛋白活性受磷酸酶与激酶的调控。尽管其调控机制尚未完全阐明，但硝酸还原酶活性可响应光暗周期、UV-B辐射等环境信号。本研究已明确玉米中调控硝酸还原酶活性的遗传因子的定位，以及各因子的贡献程度——这些因子既包括叶组织内的本地调控因子，也包括在叶片接受UV辐照后通过长距离信号位点影响根系硝酸还原酶活性的调控因子。在IBM94重组自交系作图群体中，调控UV-B辐照下硝酸还原酶活性的遗传位点，与未受辐照植株中调控硝酸还原酶活性的位点位于基因组的不同位置。