Coleto Inmaculada, de la Peña Marlon, Rodríguez-Escalante Jon, Bejarano Iraide, Glauser Gaëtan, Aparicio-Tejo Pedro M, González-Moro M Begoña, Marino Daniel
Department of Plant Biology and Ecology, University of the Basque Country (UPV/EHU), Apdo. 644, E-48080, Bilbao, Spain.
Neuchâtel Platform of Analytical Chemistry, University of Neuchâtel, Avenue de Bellevaux 51, 2000, Neuchâtel, Switzerland.
BMC Plant Biol. 2017 Sep 20;17(1):157. doi: 10.1186/s12870-017-1100-9.
The coordination between nitrogen (N) and sulfur (S) assimilation is required to suitably provide plants with organic compounds essential for their development and growth. The N source induces the adaptation of many metabolic processes in plants; however, there is scarce information about the influence that it may exert on the functioning of S metabolism. The aim of this work was to provide an overview of N and S metabolism in oilseed rape (Brassica napus) when exposed to different N sources. To do so, plants were grown in hydroponic conditions with nitrate or ammonium as N source at two concentrations (0.5 and 1 mM).
Metabolic changes mainly occurred in leaves, where ammonium caused the up-regulation of enzymes involved in the primary assimilation of N and a general increase in the concentration of N-compounds (NH, amino acids and proteins). Similarly, the activity of key enzymes of primary S assimilation and the content of S-compounds (glutathione and glucosinolates) were also higher in leaves of ammonium-fed plants. Interestingly, sulfate level was lower in leaves of ammonium-fed plants, which was accompanied by the down-regulation of SULTR1 transporters gene expression.
The results highlight the impact of the N source on different steps of N and S metabolism in oilseed rape, notably inducing N and S assimilation in leaves, and put forward the potential of N source management to modulate the synthesis of compounds with biotechnological interest, such as glucosinolates.
氮（N）和硫（S）同化之间的协调作用对于为植物的发育和生长提供必需的有机化合物至关重要。氮源可诱导植物中许多代谢过程的适应性变化；然而，关于其对硫代谢功能可能产生的影响的信息却很少。这项工作的目的是概述油菜（Brassica napus）在暴露于不同氮源时的氮和硫代谢情况。为此，将植物种植在水培条件下，以硝酸盐或铵作为氮源，设置两种浓度（0.5和1 mM）。
代谢变化主要发生在叶片中，铵导致参与氮初级同化的酶上调，以及氮化合物（NH、氨基酸和蛋白质）浓度普遍增加。同样，在以铵为养分的植物叶片中，初级硫同化关键酶的活性和硫化合物（谷胱甘肽和芥子油苷）的含量也更高。有趣的是，以铵为养分的植物叶片中的硫酸盐水平较低，同时伴随着SULTR1转运蛋白基因表达的下调。
这些结果突出了氮源对油菜氮和硫代谢不同步骤的影响，特别是诱导叶片中的氮和硫同化，并提出了通过氮源管理来调节具有生物技术意义的化合物（如芥子油苷）合成的潜力。
