Nitro-Fatty Acids in Plant Signaling: Nitro-Linolenic Acid Induces the Molecular Chaperone Network in Arabidopsis

Abstract

ORCID IDs: 0000-0002-6609-7242 (C.M.-P); 0000-0002-2210-9547 (B.S.-C.); 0000-0001-5284-8837 (J.J.-R.); 0000-0002-1814-9212 (F.J.C.); 0000-0002-9477-9195 (J.J.B.).Nitro-fatty acids (NO 2 -FAs) are the product of the reaction between reactive nitrogen species derived of nitric oxide (NO) and unsaturated fatty acids. In animal systems, NO 2 -FAs are considered novel signaling mediators of cell function based on a proven antiinflammatory response. Nevertheless, the interaction of NO with fatty acids in plant systems has scarcely been studied. Here, we examine the endogenous occurrence of nitro-linolenic acid (NO 2 -Ln) in Arabidopsis and the modulation of NO 2 -Ln levels throughout this plant's development by mass spectrometry. The observed levels of this NO 2 -FA at picomolar concentrations suggested its role as a signaling effector of cell function. In fact, a transcriptomic analysis by RNA-seq technology established a clear signaling role for this molecule, demonstrating that NO 2 -Ln was involved in plant defense response against different abiotic-stress conditions, mainly by inducing heat shock proteins and supporting a conserved mechanism of action in both animal and plant defense processes. Bioinformatics analysis revealed that NO 2 -Ln was also involved in the response to oxidative stress conditions, mainly depicted by H 2 O 2 , reactive oxygen species, and oxygen-containing compound responses, with a high induction of ascorbate peroxidase expression. Closely related to these results, NO 2 -Ln levels significantly rose under several abiotic-stress conditions such as wounding or exposure to salinity, cadmium, and low temperature, thus validating the outcomes found by RNA-seq technology. Jointly, to our knowledge, these are the first results showing the endogenous presence of NO 2 -Ln in Arabidopsis (Arabidopsis thaliana) and supporting the strong signaling role of these molecules in the defense mechanism against different abiotic-stress situations.

Plant peroxisomes: A nitro-oxidative cocktail

“…These include molecules such as S -nitrosothiols (SNOs), S -nitrosoglutathione (GSNO), peroxynitrite (ONOO - ) and nitro-fatty acids (NO 2 -FA), which directly or indirectly perform a broad spectrum of regulatory functions in many physiological and pathological processes in higher plants [31], [38], [76], [121]. It is worth noting that plant peroxisomes were the first organelles found to show the presence of L -arginine-dependent nitric oxide synthase, a NOS-like activity with biochemical requirements ( L -Arg, NADPH, FMN, FAD, CaM and Ca 2+ ) similar to those of animal NOS [7].…”

Nitro-fatty acid pharmacokinetics in the adipose tissue compartment

“…Wherever possible, the maximum area for each tissue within a single autoradiogram was defined for measurement. These radiolabeling experiments were conducted at Huntingdon Life Sciences (Cambridgeshire, and extra virgin olive oil (15,16). Notably, plasma and urinary NO 2 -FA concentrations in humans are increased following oral supplementation with NO 2  , nitrate (NO 3  ), and conjugated linoleic acid (CLA) (17,18 18 ]OA) were synthesized by direct alkene nitroselenation of the corresponding native FAs, as previously described (21).…”

Assessing Nitric Oxide (NO) in Higher Plants: An Outline

“…With respect to the latter group, can be mentioned, and it is particularly worth highlighting the interaction of NO with the tripeptide glutathione (GSH) leading to the formation of S-nitrosoglutathione (GSNO) within cells [12]. Moreover, there is increased information about how NO can modulate gene expression [13][14][15][16], as well as new related molecules, like nitro-fatty acids (NO 2 -FA), which have signaling properties [17]. The majority of the research reports on plants have been basically focused on how NO regulates protein functions.…”

“…Thus, recently, the presence of nitro-linolenic acid has been identified in the model plants Arabidopsis thaliana, the abundance of nitro-linolenic acid which changes during the development, the seeds being the organ with the higher concentration. Moreover, it was found that this molecule had signal functions under several abiotic stresses [17] with the capacity to release NO [41]. Outline of nitric oxide (NO) metabolism in plant cells.…”