The Synergistic Priming Effect of Exogenous Salicylic Acid and H2O2 on Chilling Tolerance Enhancement during Maize (Zea mays L.) Seed Germination

Abstract

Chilling stress is an important constraint for maize seedling establishment in the field. To examine the role of salicylic acid (SA) and hydrogen peroxide (H2O2) in response to chilling stress, we investigated the effects of seed priming with SA, H2O2, and SA+H2O2 combination on maize resistance under chilling stress (13°C). Priming with SA, H2O2, and especially SA+H2O2 shortened seed germination time and enhanced seed vigor and seedling growth as compared with hydropriming and non-priming treatments under low temperature. Meanwhile, SA+H2O2 priming notably increased the endogenous H2O2 and SA content, antioxidant enzymes activities and their corresponding genes ZmPAL, ZmSOD4, ZmAPX2, ZmCAT2, and ZmGR expression levels. The α-amylase activity was enhanced to mobilize starch to supply metabolites such as soluble sugar and energy for seed germination under chilling stress. In addition, the SA+H2O2 combination positively up-regulated expressions of gibberellic acid (GA) biosynthesis genes ZmGA20ox1 and ZmGA3ox2, and down-regulated GA catabolism gene ZmGA2ox1 expression; while it promoted GA signaling transduction genes expressions of ZmGID1 and ZmGID2 and decreased the level of seed germination inhibitor gene ZmRGL2. The abscisic acid (ABA) catabolism gene ZmCYP707A2 and the expressions of ZmCPK11 and ZmSnRK2.1 encoding response receptors in ABA signaling pathway were all up-regulated. These results strongly suggested that priming with SA and H2O2 synergistically promoted hormones metabolism and signal transduction, and enhanced energy supply and antioxidant enzymes activities under chilling stress, which were closely relevant with chilling injury alleviation and chilling-tolerance improvement in maize seed.Highlights:Seed germination and seedling growth were significantly improved under chilling stress by priming with SA+H2O2 combination, which was closely relevant with the change of reactive oxygen species, metabolites and energy supply, hormones metabolism and regulation.

The Integration of Bio and Organic Fertilizers Improve Plant Growth, Grain Yield, Quality and Metabolism of Hybrid Maize (Zea mays L.)

“…Briefly, a frozen seed sample (100 mg) was ground in liquid nitrogen using a mortar and pestle and QRT-PCR was carried out according to the method of Salah et al [30]. Primers used in QRT-PCR and shown in Table S2 were the same as those used in a recent study [2]. ACT1 was used as a control to measure the transcript levels of the other studied genes.…”

“…Maize (Zea mays L.) is one of the most important cereal crops in the world both as food and feed. Its total world production ranks third, following wheat and rice, and it is consider a staple food in many countries, especially those in the tropics and sub-tropics [1][2][3][4]. In Egypt, maize is considered the second most important crop, where the annual production of the grain reached about 6.8 million tons from 315,000 hectares in 2018 [5].…”

Hydropriming and Biopriming Improve Medicago truncatula Seed Germination and Upregulate DNA Repair and Antioxidant Genes

“…Hence, an interesting aspect of seed priming relates to the boost of seed germination and seedling establishment under non-optimal conditions. Several studies reported that seed priming can alleviate stress levels in seedlings and this can result in better productivity levels under environmental constraints [13,[19][20][21][22].…”

Reactive Oxygen Species and Gibberellin Acid Mutual Induction to Regulate Tobacco Seed Germination

“…Hydrogen peroxide (H 2 O 2 ) is considered as the ROS messenger for long-distance transport in cells ( Moller, 2001 ; Möller and Sweetlove, 2010 ), the stimulation of downstream transcription, and the activation of mitogen-activated protein kinases (MAPKs) ( Neill S. et al, 2002 ). Exogenous H 2 O 2 stimulates seed germination of Arabidopsis ( Arabidopsis thaliana L.), maize ( Zea mays L.), and sunflower seeds by enhancing GA biosynthesis and ABA catabolism ( Maarouf et al, 2015 ; Huang et al, 2017 ; Li et al, 2017 ). Nevertheless, H 2 O 2 releases embryo dormancy in barley by activating GA signaling and synthesis rather than the repression of ABA signaling ( Bahin et al, 2011 ).…”