Soil bacteria conferred a positive relationship and improved salt stress tolerance in transgenic pea (Pisum sativum L.) harboring Na+/H+ antiporter

Authors: ZAHID ALI, NASR ULLAH, SAADIA NASEEM, MUHAMMAD INAM UL HAQ, HANS JOERG JACOBSEN

Abstract: Among grain legumes, peas (Pisum sativum L.) are highly sensitive to salt stress. Acclimatization of plants to such conditions is mandatory. We provide improved salt stress tolerance response of transgenic pea plants overexpressing the Na⁺/H⁺ gene from Arabidopsis thaliana and a positive association with salt-tolerant plant growth-promoting rhizobacteria (PGPR). In addition to salt stress tolerance and phosphate solubilization, the selected rhizobacterial isolates were identified for indole acetic acid and proline production ability. Seed germination percentage in transgenic pea plants was significantly higher under NaCl challenge. The wild-type (WT) pea plants inoculated with known numbers of viable cells of salt-tolerant PGPR and transgenic pea plants without any inoculation showed better growth performance under salt stress. However, the PGPR-inoculated transgenic plants showed significant increase in growth and biomass compared to the WT counterpart. An increase in antioxidant enzymes, i.e. Superoxide dismutase and peroxidases, was observed in PGPR-inoculated transgenic plants under salt stress. We could not see any negative effect of the transgene in pea plants on the growth of associated PGPR. The overall impact of microbe-mediated elicitation responses in transgenic plants, whether at the biochemical or molecular level, may lead to protection against salt stress.

Keywords: Salt stress tolerance, transgenic plants, Na+/H+ antiporter, plant growth-promoting rhizobacteria, Pisum sativum L.

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