Exogenous trehalose mitigates abiotic stress in plants by improving morphophysiology: a meta-analysis

Trehalose plays a crucial role in protecting plants against abiotic stresses, such as water deficit, salinity, cold, heat, and heavy metal excess. Although numerous studies exist on its use as a biostimulant, integrated analyses that quantitatively and systematically evaluate the consistency of these effects are still lacking. Therefore, this meta-analysis aimed to assess whether the exogenous application of trehalose mitigates the effects of abiotic stress in plants and to investigate the underlying morphophysiological mechanisms. To this end, a systematic search was conducted in the Web of Science database, and the resulting articles were subjected to a meta-analysis. The overall effect size and the effects by moderators (stress types and application methods) were calculated. The initial screening of 659 records yielded 52 eligible publications. The identified exogenous application methods were foliar spray, root application, and seed priming. The results demonstrate that trehalose increases the contents of starch, soluble sugars, proline, and photosynthetic pigments, and enhances chlorophyll fluorescence. It also improves enzymatic and non-enzymatic antioxidant activities, elevates leaf gas exchange and water status, and reduces lipid peroxidation, H2O2 accumulation, and membrane permeability. At an agronomic level, it promotes greater growth, shoot development, leaf area, and grain yield. The collated evidence indicates that trehalose can be exogenously applied as an inducer of tolerance to multiple abiotic stresses. Thus, the use of trehalose is recommended to mitigate the adverse effects of abiotic stress and enhance agricultural productivity.