Effect of drought stress on wheat (Triticum durum) growth and metabolism: insight from GABA shunt, reactive oxygen species and dehydrin genes expression

Abstract

Activation of γ-aminobutyric acid (GABA) shunt pathway and upregulation of dehydrins are involved in metabolic homeostasis and protective mechanisms against drought stress. Seed germination percentage, seedling growth, levels of GABA, alanine, glutamate, malondialdehyde (MDA), and the expression of glutamate decarboxylase (GAD) and dehydrin (dhn and wcor) genes were examined in post-germination and seedlings of four durum wheat (Triticum durum L.) cultivars in response to water holding capacity levels (80%, 50%, and 20%). Data showed a significant decrease in seed germination percentage, seedling length, fresh and dry weight, and water content as water holding capacity level was decreased. Levels of GABA, alanine, glutamate, and MDA were significantly increased with a negative correlation in post-germination and seedling stages as water holding capacity level was decreased. Prolonged exposure to drought stress increased the GAD expression that activated GABA shunt pathway especially at seedlings growth stage to maintain carbon/nitrogen balance, amino acids and carbohydrates metabolism, and plant growth regulation under drought stress. The mRNA transcripts of dhn and wcor significantly increased as water availability decreased in all wheat cultivars during the post-germination stage presumably to enhance plant tolerance to drought stress by cell membrane protection, cryoprotection of enzymes, and prevention of reactive oxygen species (ROS) accumulation. This study showed that the four durum wheat cultivars responded differently to drought stress especially during the seedling growth stage which might be connected with ROS scavenging systems and the activation of antioxidant enzymes that were associated with activation of GABA shunt pathway and the production of GABA in durum seedlings.

Dehydrin CaDHN2 Enhances Drought Tolerance by Affecting Ascorbic Acid Synthesis under Drought in Peppers

“…The overexpression of dehydrins in various plant species, including crops like wheat and ornamental plants like Ammopiptanthus nanus, has been shown to enhance tolerance to drought, salt, and cold stresses. This indicates that the increased expression of dehydrins confers enhanced stress tolerance in different plant species across different contexts [42,57]. The silencing of CaDHNs has been observed to decrease the tolerance of plants to cold, salt, and drought stresses [17].…”

“…The accumulation of dehydrins enhances drought, chilling, and salt tolerance [40,41]. In plant cells, dehydrins can maintain cell stabilization and homeostasis They help prevent cell dehydration, eliminate free radicals, protect macromolecules, and bind metal ions [37,42,43]. Li et al found that dehydrin MtCAS31, which functions as a cargo receptor, participates in autophagy degradation in response to drought stress in Medicago [40].…”

Neodymium Nitrate Improves the Germination of Aged Wheat Seeds by Increasing Soluble Substances and Activating Antioxidative and Metabolic Enzymes in Seeds

“…Recent studies of the GABA shunt pathway have shown that its function is required for proper growth in response to abiotic stresses [76]. GABA is the product of glutamate decarboxylase, and thus its abundance reflects the activity of GAD [77]. Xu reported that GABA metabolism is a novel mechanism to improve plant stress resistance [78].…”

Proteomic Analysis Reveals Salt-Tolerant Mechanism in Soybean Applied with Plant-Derived Smoke Solution

“…In contrast, gamma-aminobutyric acid in soybean increased with PDS solution alone ( Figure 7 B). Wheats responded to drought stress during the seedling stage, which related to reactive oxygen species scavenging systems and the activation of antioxidant enzymes, which were associated with activation of the gamma-aminobutyric acid shunt pathway and its production [ 58 ]. Additionally, the sonication or hydropriming treatments significantly improved the germination performance of wheat and enhanced gamma-aminobutyric acid metabolism to maintain the C:N metabolic balance under cold stress [ 59 ].…”