Abscisic acid and hydrogen peroxide are involved in drought priming‐induced drought tolerance in wheat (Triticum aestivum L.)

Abstract

Drought is one of the major stress factors in wheat production on a global scale. Drought priming during the early growth stage can enhance drought tolerance in wheat (Triticum aestivum L.). Abscisic acid (ABA) and hydrogen peroxide (H2O2) are important signal molecules in the adaptation of plants to drought stress. However, the roles of ABA and H2O2 in drought priming‐induced drought tolerance are not clear. In the present study, we evaluated the responses of wheat to an ABA inhibitor, H2O2 scavenger and an inhibitor to investigate the (i) relationship between ABA and H2O2 in osmotic adjustment after drought priming in the vegetative stage and (ii) responses to drought stress during grain filling. In the drought priming alone treatments, chemical application resulted in the scavenging of ABA and H2O2, weakening the alleviation effects of drought priming on drought stress, as demonstrated by the lower leaf water potential and grain yield. The ABA inhibitor completely inhibited accumulation of ABA and H2O2; the ABA inhibitor inhibited respiratory burst oxidase homologue expression, whereas the H2O2 inhibitor resulted in higher 9‐cis‐epoxycarotenoid dioxygenase expression and ABA concentration in primed plants, indicating that ABA scavenging inhibited H2O2 biosynthesis while H2O2 scavenging did not inhibit ABA biosynthesis. The results further demonstrated that NADPH oxidase‐mediated H2O2 production functions downstream of ABA, which induces osmolyte transcript expression and accumulation, and thus contributes to drought priming‐induced stress tolerance. These results provide a theoretical basis for a better understanding of the mechanisms involved in drought priming‐induced tolerance in wheat plants.

Crosstalk between hydrogen peroxide and nitric oxide mediates priming‐induced drought tolerance in wheat

“…The expression of the proline synthesis related enzyme Δ1‐pyrroline‐5‐carboxylate synthetase ( P5CS ) and of proline dehydrogenase ( PDH ) was in line with the proline content in the treatments of primed plants (Figure 6). Our previous study found that ABA is required for drought priming induced osmolyte accumulation and that inhibitors of ABA biosynthesis suppressed drought priming induced osmolyte accumulation (Wang, Li, et al., 2020; Wang, Zhang, et al., 2020). Here, the contents of osmolytes were in agreement with the contents ABA and NO, but not with NR activities.…”

“…Heat priming or treatment with NO donor and H 2 O 2 increased wheat seedlings resistance to heat‐damage, while scavengers of NO (c‐PTIO) and H 2 O 2 (DMTU) inhibited the heat‐resistance induced by heat priming, suggesting a crosstalk between NO and H 2 O 2 (Karpets et al., 2015). Our previous study showed that drought priming during an early stage induced the tolerance to drought occurring at a later growth stage and that H 2 O 2 mediates abscisic acid (ABA) involved in drought priming, thereby contributing to drought tolerance in wheat (Wang, Li, et al., 2020; Wang, Zhang, et al., 2020). In this study, scavenging of H 2 O 2 and NO followed by drought priming significantly increased the relative electrical conductivity in the primed plants under drought stress in wheat seedlings.…”

“…In this study, scavenging of H 2 O 2 and NO followed by drought priming significantly increased the relative electrical conductivity in the primed plants under drought stress in wheat seedlings. Our previous study found that the scavenging of H 2 O 2 followed by drought priming during the seedling stage resulted in lower grain yield than in primed plants under drought stress during the grain filling stage (Wang, Li, et al., 2020; Wang, Zhang, et al., 2020). In this study, the scavenging of NO under drought stress (data not shown) resulted in similar effects on grain yield, suggesting that NO and H 2 O 2 mediated priming‐induced drought tolerance in wheat.…”

“…In Arabidopsis seedlings, the endogenous phytohormones abscisic acid (ABA) and jasmonic acid (JA) are involved in priming‐induced ‘stress memory’ (Ding et al., 2012; Li et al., 2019). Our recent study showed that ABA and JA are required for priming‐induced drought tolerance in wheat (Wang, Li, et al., 2020; Wang, Zhang, et al., 2020).…”

Phosphatidic acid and hydrogen peroxide coordinately enhance heat tolerance in tall fescue

“…2019; Wang et al . 2020). Tall fescue ( Festuca arundinacea ) is one of the most widely used cool‐season grass species as forage and turf and is sensitive to heat stress, with loss of forage yield and turf quality during summer months (Wang et al .…”