Nitric oxide release from nitro-fatty acids in Arabidopsis roots.

In recent years, research on the involvement of nitric oxide (NO) in plant systems has remarkably grown. However, most of the interest in this molecule has been focused on its ability to mediate different post-translational modifications (NO-PTM) in biomolecules, mainly nitration and S-nitrosylation of proteins, and its involvement in physiological and stress situations. Nevertheless, very recently the nitration of other molecules such as fatty acids has commanded increasingly greater attention. In the last February issue of Plant Physiology, we again reported on the endogenous occurrence of nitro-fatty acids (NO2-FAs), specifically nitro-linolenic acid (NO2-Ln), in the model plant Arabidopsis thaliana. The analysis of the presence of this nitro-fatty acid showed that levels of NO2-Ln decreased throughout the plant development with the higher levels detected in seeds and young seedlings of this plant. Furthermore, through a transcriptomic analysis by RNA-seq technology applying NO2-Ln to A. thaliana cell-suspension cultures, we found high induction in the transcriptional expression of several heat-shock proteins (HSPs) and the enzymes ascorbate peroxidase (APX) and methionine sulfoxide reductase (MSR). Based on these findings, the involvement of NO2-Ln in the NO metabolism was analyzed showing a significant NO formation in roots from 7-day-old Arabidopsis thaliana seedlings and standing out that NO generated from NO2-Ln could have an important role at the beginning of plant development. Therefore, these findings highlight the importance of these novel NO-derived molecules in plant systems playing a pivotal role in development and in the antioxidant defense response against different abiotic stress conditions.