Improvement of durum wheat growth under combined abiotic stresses by multitolerant strain of Pantoea agglomerans for sustainable agricultural approach

Abiotic stress is one of the greatest constraints on crop productivity. Although individual stress factors such as salinity, drought, heavy metals and pollutants can affect plant growth, their combination leads to even more devastating effects on plant growth and productivity. In this study, the effect of the multitolerant strain Pantoea agglomerans Pa on the growth of durum wheat (Triticum durum L.) under stress conditions such as drought (25% of field capacity), salinity (200 mM NaCl), heavy metal (cadmium, 200 ppm) and pollutant (phenanthrene, 200 ppm) was investigated. These parameters were assessed individually and in combinations (double, triple and quadruple). The results showed that Pa significantly (P ≤ 0.05) improved morphological parameters and chlorophyll content while reducing electrolyte loss, malondialdehyde and proline levels. In addition, the activities of antioxidant enzymes (ascorbate peroxidase, catalase, guaiacol peroxidase and superoxide dismutase) enhanced the protective effect of Pa against combined stress factors. These results emphasise the potential of Pa to maintain its plant growth-promoting properties including phosphate solubilisation, indole-3-acetic acid production and siderophore production under various stress conditions. This suggests that P. agglomerans Pa has the potential to promote sustainable agriculture by protecting plants from both single and combined abiotic stress factors.