Integrative Network Analysis of Physiological, Transcriptomic, and Metabolomic Profiles Reveals the Mechanism of Propionic Acid-Mediated Alleviation of Cadmium Toxicity in Wheat (Triticum aestivum L.)

Cadmium (Cd), a pervasive toxic metal, poses significant
detrimental
effects on plant development and yield. Exogenous propionic acid (PA)
application significantly alleviated Cd toxicity in wheat seedlings.
Based on physiological analysis, exogenous 10 μM PA treatment
significantly reduced Cd accumulation by 36.29% in the shoot and 25.79%
in the root under 20 μM Cd treatment. Integrative transcriptomic
and metabolomic analyses revealed that PA enhances the antioxidant
capacity via activation of branched-chain amino acid (BCAA) metabolism
and salicylic acid (SA) signaling. Furthermore, PA upregulates TaHSP20 expression through H2O2 signaling,
promoting pectin synthesis and demethylation to improve Cd chelation
in the cell wall. Additionally, PA activates abscisic acid (ABA) signaling,
inducing the expression of TaHSP20 and TaHSP70 to reinforce cell wall biosynthesis and Cd sequestration. Key metabolites
such as sedoheptulose and rhamnose may further facilitate Cd2+ immobilization within the cell wall. These findings elucidate a
systemic mechanism underlying PA-mediated alleviation of Cd toxicity,
offering new strategies for improving agroecological sustainability.