Metabolic Profiling Reveals Increased Nitrogen Remobilization in Potato Plants that Express a Cyanobacterial NO/NO3−-Producing Enzyme

Abstract

Potato crop production significantly contributes to human nutritional needs. The continuous cropping of potatoes depletes the soil of macronutrients, such as nitrogen (N). Excessive use of nitrogenous fertilizers to ensure N availability has been linked to environmental pollution and greenhouse gas emissions. Thus, understanding metabolism of the potato plant, its response to N limitation and how to achieve maximum yield in poor soils, could thus be an important highway for smart crop production. Here, we present a gas chromatography—mass spectrometry -based metabolomics analysis of potato plants grown under contrasting N conditions. Data show that a reduction in N availability causes a decreased in the abundance of several amino acids but an increase in most carbohydrates. In a previous article, we have shown that the heterologous expression of a Globin/Nitric Oxide Synthase chimera (SyNOS) from cyanobacteria improves N-deficiency tolerance in Arabidopsis. This work aims to describe the effect of SyNOS expression on the N metabolism of a crop plant. Thus, we expressed SyNOS in potato, grew the resultant transgenics under contrasting N conditions, and evaluated their responses. SyNOS expression partially prevents the adverse effects of N deficiency on the contents of specific amino acids in potato. Nitrate reductase activity and mRNA levels of nitrite reductase and glutamine synthetase were less affected by N deficiency in SyNOS transgenic potato. Collectively, the results presented here indicate that sustaining an active N metabolism and recycling N-containing molecules such as arginine, nitric oxide and nitrate, are potential targets for improving potato crop production.