Organ-dependent oxylipin signature in leaves and roots of salinized tomato plants (Solanum lycopersicum)

Abstract

Oxylipins have been extensively studied in plant defense mechanisms or as signal molecules. Depending on the stress origin (e.g. wounding, insect, pathogen), and also on the plant species or organ, a specific oxylipin signature can be generated. Salt stress is frequently associated with secondary stress such as oxidative damage. Little is known about the damage caused to lipids under salt stress conditions, especially with respect to oxylipins. In order to determine if an organ-specific oxylipin signature could be observed during salt stress, tomato (Solanum lycopersicum cv. Money Maker) plants were submitted to salt stress (100 mM of NaCl) for a 30-d period. A complete oxylipin profiling and LOX related-gene expression measurement were achieved in leaves and roots. As expected, salt stress provoked premature senescence in leaves, as revealed by a decrease in photosystem II efficiency (F(v)/F(m) ratio) and sodium accumulation in leaves. In roots, a significant decrease in several oxylipins (9- and 13-hydro(pero)xy linole(n)ic acids, keto and divinyl ether derivatives) was initiated at day 5 and intensified at day 21 after salt treatment, whereas jasmonic acid content increased. In leaves, the main changes in oxylipins were observed later (at day 30), with an increase in some 9- and 13-hydro(pero)xy linole(n)ic acids and a decrease in some keto-derivatives and in jasmonic acid. Oxylipin enantiomeric characterization revealed that almost all compounds were formed enzymatically, and therefore a massive auto-oxidation of lipids that can be encountered in abscission processes can be excluded here.

The Persimmon 9-lipoxygenase Gene DkLOX3 Plays Positive Roles in Both Promoting Senescence and Enhancing Tolerance to Abiotic Stress

“…These results provide the evidence for the possibility that DkLOX3 or DkLOX3 -derived products play a positive role in abiotic stresses response by modulating the expression of ABA-dependent and other stress-responsive genes. Several studies also found that products of lipid derivatives were suggested to act as secondary messengers to activate some stress-associated genes and activate the response of the plant to desiccation and salinity ( Ingram and Bartels, 1996 ; Shinozaki and Yamaguchi-Shinozaki, 1997 ; Ben-Hayyim et al, 2001 ; Sofo et al, 2004 ; Ghanem et al, 2012 ). In CaLOX1 -OX plants under ABA treatment as well as normal conditions, smaller stomatal aperture was both found and this indicated CaLOX1 or CaLOX1 -derived oxylipins played a role in ABA-independent stomatal closure, nevertheless, with drought and salinity treatments, ABA-induced gene expression in CaLOX1 -OX Arabidopsis was enhanced ( Lim et al, 2015 ).…”

Plant–Pathogen Interactions: Underestimated Roles of Phyto-oxylipins

“…PO signatures are influenced by the type of stressor, the plant species being stressed, and the affected organ(s), as well as by the pathogen lifestyle (for reviews see [4,18,[31][32][33][34][35][36][37][38]). For instance, tobacco (Nicotiana tabacum) leaves infected by the hemibiotroph Pseudomonas syringae accumulate high levels of α-dioxygenase (α-DOX) and 9-lipoxygenase (LOX) products [39], whereas certain potato cultivars infected by Phytophthora infestans and tomato leaves infected by necrotrophic Botrytis cinerea accumulate 9(S)-and 13(S)-polyunsaturated fatty acid (FA) (PUFA) hydroperoxides (HPOs) [40][41][42].…”

Synthesis and Functions of Jasmonates in Maize

“…Depending on plant species and tissue specificity [47], this pathway produces diverse subsets of alcohols, aldehydes, divinyl ethers, esters, epoxides, hydroxides, hydroperoxides, ketols, ketones and triols [46,48] (Figure 3). These metabolites are implicated in nearly all plant biological processes that include defense, development and trans-kingdom communication [40,49].…”