AUTHOR=Pilarska Maria , Wiciarz Monika , Jajić Ivan , Kozieradzka-Kiszkurno Małgorzata , Dobrev Petre , Vanková Radomíra , Niewiadomska Ewa 

TITLE=A Different Pattern of Production and Scavenging of Reactive Oxygen Species in Halophytic Eutrema salsugineum (Thellungiella salsuginea) Plants in Comparison to Arabidopsis thaliana and Its Relation to Salt Stress Signaling

JOURNAL=Frontiers in Plant Science

VOLUME=7

YEAR=2016

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2016.01179

DOI=10.3389/fpls.2016.01179

ISSN=1664-462X

ABSTRACT=<p>Isolated thylakoids from halophytic <italic>Eutrema salsugineum</italic> (<italic>Thellungiella salsuginea</italic>) produces more H<sub>2</sub>O<sub>2</sub> in comparison to glycophytic <italic>Arabidopsis thaliana</italic>. The first objective of this study was to verify whether this feature is relevant also to the intact chloroplasts and leaves. Enhanced H<sub>2</sub>O<sub>2</sub> levels in chloroplasts and leaves of <italic>E. salsugineum</italic> were positively verified with several methods (electron microscopy, staining with Amplex Red and with diaminobenzidine). This effect was associated with a decreased ratio of <inline-formula><mml:math id="M1" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msubsup><mml:mi mathvariant="normal" mathcolor="black">O</mml:mi><mml:mi mathvariant="normal" mathcolor="black">2</mml:mi><mml:mn mathvariant="normal" mathcolor="black">•–</mml:mn></mml:msubsup></mml:math></inline-formula>/H<sub>2</sub>O<sub>2</sub> in <italic>E. salsugineum</italic> in comparison to <italic>A. thaliana</italic> as detected by electron paramagnetic resonance method. As a next step, we tested how this specific ROS signature of halophytic species affects the antioxidant status and down-stream components of ROS signaling. Comparison of enzymatic antioxidants revealed a decreased activity of ascorbate peroxidase (APX), enhanced activity of glutathione peroxidase, and the presence of thylakoid-bound forms of iron superoxide dismutase (FeSOD) and APX in <italic>E. salsugineum</italic>. These cues were, however, independent from application of salt stress. The typical H<sub>2</sub>O<sub>2</sub>-dependent cellular responses, namely the levels of glucosinolates and stress-related hormones were determined. The total glucosinolate content in <italic>E. salsugineum</italic> water-treated leaves was higher than in <italic>A. thaliana</italic> and increased after salinity treatment. Treatment with salinity up-regulated all of tested stress hormones, their precursors and catabolites [abscisic acid (ABA), dihydrophaseic acid, phaseic acid, 1-aminocyclopropane-1-carboxylic acid, salicylic acid, jasmonic acid, <italic>cis</italic>-(+)-12-oxo-phytodienoic acid and jasmonoyl-<sc>L</sc>-isoleucine] in <italic>A. thaliana</italic>, whereas in <italic>E. salsugineum</italic> only a stimulation in ethylene synthesis and ABA catabolism was noted. Obtained results suggest that constitutively enhanced H<sub>2</sub>O<sub>2</sub> generation in chloroplasts of <italic>E. salsugineum</italic> might be a crucial component of stress-prepardeness of this halophytic species. It shapes a very efficient antioxidant protection (in which glucosinolates might play a specific role) and a fine tuning of hormonal signaling to suppress the cell death program directed by jasmonate pathway.</p>