H2O2 and Ca2+ Signaling Crosstalk Counteracts ABA to Induce Seed Germination

Abstract

Seed germination is a critical stage and the first step in the plant’s life cycle. H2O2 and Ca2+ act as important signal molecules in regulating plant growth and development and in providing defense against numerous stresses; however, their crosstalk in modulating seed germination remains largely unaddressed. In the current study, we report that H2O2 and Ca2+ counteracted abscisic acid (ABA) to induce seed germination in melon and Arabidopsis by modulating ABA and gibberellic acid (GA3) balance. H2O2 treatment induced a Ca2+ influx in melon seeds accompanied by the upregulation of cyclic nucleotide-gated ion channel (CNGC) 20, which encodes a plasma membrane Ca2+-permeable channel. However, the inhibition of cytoplasmic free Ca2+ elevation in the melon seeds and Arabidopsis mutant atcngc20 compromised H2O2-induced germination under ABA stress. CaCl2 induced H2O2 accumulation accompanied by the upregulation of respiratory burst oxidase homologue (RBOH) D and RBOHF in melon seeds with ABA pretreatment. However, inhibition of H2O2 accumulation in the melon seeds and Arabidopsis mutant atrbohd and atrbohf abolished CaCl2-induced germination under ABA stress. The current study reveals a novel mechanism in which H2O2 and Ca2+ signaling crosstalk offsets ABA to induce seed germination. H2O2 induces Ca2+ influx, which in turn increases H2O2 accumulation, thus forming a reciprocal positive-regulatory loop to maintain a balance between ABA and GA3 and promote seed germination under ABA stress.

Characterization of ZmPMP3g function in drought tolerance of maize

“…This is roughly consistent with our findings in this study (Fig. 7 d), indicating that ZmPMP3g overexpression can harmonize the ABA-GA1-GA3 (especially GA1) balance, somewhat different from the homeostasis of ABA-GA3 in melon ( Cucumis melo ) seeds under treatments with exogenous ABA 45 and ABA-GA3-GA4 (especially GA4) during early growth stage of cucumber ( C. sativus ) treated by melatonin under salt 43 .…”

“…DELLA degradation is also involved in COP1, FKF1/F-box, skp1, CUL1, and F-box proteins 38 . However, accumulating evidence shows that GA and ABA exert an antagonistic effect and need a balance/homeostasis in plants 39 – 42 , high GA and low ABA levels under favorable conditions and the reverse ratio under unfavorable conditions 43 – 45 . This is roughly consistent with our findings in this study (Fig.…”

Strigolactone Alleviates the Adverse Effects of Salt Stress on Seed Germination in Cucumber by Enhancing Antioxidant Capacity

“…This critical developmental step is regulated by diverse endogenous and exogenous factors [17]. Previous results reveal that seed germination is positively regulated by some novel singling molecules, such as H 2 S [18], H 2 O 2 [19], Ga 2+ [19], ABA [19], NO [20], and CO [21]. Additionally, an increasing number of studies have recently reported that plant hormones promote seed germination, such as ABA, auxin, ET, GA, CK, JA, and BRs [22].…”

ABA Inhibits Rice Seed Aging by Reducing H2O2 Accumulation in the Radicle of Seeds

“…Seed aging represents an irreversible process characterized by the gradual decline of seed vigor, including reduction in antioxidant systems, disruption of cellular membranes, genetic integrity damage, lipid peroxidation, and protein degradation [ 29 , 30 , 31 , 32 ]. ROS serve as key modulators of seed aging, initiating early bursts during accelerated aging, potentially leading to dynamic changes in mitochondria and seed inactivation [ 8 , 33 ].…”