Understanding the role of H₂O₂ during pea seed germination: a combined proteomic and hormone profiling approach

Abstract

In a previous publication, we showed that the treatment of pea seeds in the presence of hydrogen peroxide (H2O2) increased germination performance as well as seedling growth. To gain insight into the mechanisms responsible for this behaviour, we have analysed the effect of treating mature pea seeds in the presence of 20 mM H2O2 on several oxidative features such as protein carbonylation, endogenous H2O2 and lipid peroxidation levels. We report that H2O2 treatment of the pea seeds increased their endogenous H2O2 content and caused carbonylation of storage proteins and of several metabolic enzymes. Under the same conditions, we also monitored the expression of two MAPK genes known to be activated by H2O2 in adult pea plants. The expression of one of them, PsMAPK2, largely increased upon pea seed imbibition in H2O2, whereas no change could be observed in expression of the other, PsMAPK3. The levels of several phytohormones such as 1-aminocyclopropane carboxylic acid, indole-3-acetic acid and zeatin appeared to correlate with the measured oxidative indicators and with the expression of PsMAPK2. Globally, our results suggest a key role of H2O2 in the coordination of pea seed germination, acting as a priming factor that involves specific changes at the proteome, transcriptome and hormonal levels.

Role of H2O2in pea seed germination

“…13 H 2 O 2 would induce a MAPK-dependent decrease in abcisic acid (ABA) contents in the seed as well as the carbonylation of seed storage proteins, 13 favoring their mobilization, and some glycolytic enzymes that could stimulate the phosphate pentose pathway (oxPPP).…”

“…15 Alternatively, H 2 O 2 could act, directly or indirectly impairing the ABA transport from the cotyledon to the embryo inducing a decrease in ABA, stimulating the germination process. 13 Finally, the decrease in ABA could induce a MAPK-mediated decrease in the ethylene precursor 1-aminocyclopropane carboxylic acid, favoring epicotyl and radicle emergence by H 2 O 2 treatment. 13 As mentioned above, the H 2 O 2 treatment also stimulates the early growth of pea seedlings (Table 1).…”

“…13 Finally, the decrease in ABA could induce a MAPK-mediated decrease in the ethylene precursor 1-aminocyclopropane carboxylic acid, favoring epicotyl and radicle emergence by H 2 O 2 treatment. 13 As mentioned above, the H 2 O 2 treatment also stimulates the early growth of pea seedlings (Table 1). Previously, we have described that the H 2 O 2 -induced increase in pea seedling growth was correlated with the induction of proteins related to plant growth, cellular signaling and cell cycle control (14-3-3 protein, profilin, proteasome, translationally-controlled tumor protein), as well as with a substantial decrease in the levels of the hormones ABA and zeatin-riboside (ZR).…”

Genomics: A Hallmark to Monitor Molecular and Biochemical Processes Leading Toward a Better Perceptive of Seed Aging and ex-situ Conservation

“…In isolated segments of maize modulated ROS yields H2O2, which boosts leaf expansion (Rodriguez et al, 2002). Moreover, in germinating pea seeds high amount of O2 − deposits at radicle expansion stage , which validates the role of O2 − in stimulating cell elongation (Passardi et al, 2004;Barba-Espin et al, 2011). Apart from their deleterious effects, ROS play a pivotal role in the signal transduction system of seed.…”

Pulsed magnetic field improves seed quality of aged green pea seeds by homeostasis of free radical content

“…Report on the positive role of ROS in germination and dormancy release show that superoxide and H 2 O 2 act as secondary messengers in plant developmental processes (Mittler et al 2004). Hydrogen peroxide acts as a priming factor that brings about changes at proteome, transcriptome and hormonal levels thereby promoting germination in pea (Barba-Espin et al 2011). H 2 O 2 production in the plants results from the reactions catalysed by cell wall associated NADH peroxidase, oxalate oxidases, Nicotinamide Adenine Dinucleotide Phosphate (reduced) (NADPH) oxidase and amine oxidases (Bolwell and Wojtaszek 1997).…”