Potential of halotolerant PGPRs in growth and yield augmentation of Triticum aestivum var. HD2687 and Zea mays var. PSCL4642 cultivars under saline conditions.

Abstract

This study aimed to culture and screen salt-tolerant Plant growth promoting rhizobacteria (PGPRs) from Bougainvillea glabra rhizosphere to improve wheat HD-2687 and maize PSCL-4642 cultivars under saline conditions up to the seedling stage. Twenty-four rhizobacterial isolates were screened for salt tolerance at different NaCl levels. Indole acetic acid (IAA) production, phosphate solubilization, and siderophore and hydrogen cyanide (HCN) production of salinity-tolerant isolates were tested. Positive salt-tolerant PGPRs were further subjected to seedling studies to examine the improvement in the development of experimental crops under 50, 100, 150, and 200 mM NaCl concentrations with/without bacterial inoculant. Of the 24 isolates, BoGl123 was the most promising PGPR, which showed the maximum phosphate solubilization, and IAA, siderophore and HCN production. It was further subjected to seedling studies. In comparison with controls, BoGl123 resulted in a higher radicle length in maize (34 mm, 87.4%) and wheat (26.8 mm, 85.8%) at the 50 mM salinity level. At the 100 mM NaCl level, the radicle length of wheat and maize seedlings was increased by 82.5% and 78.6%, respectively, compared with controls. At different NaCl concentrations, BoGl123 improved the plumule length of seedlings in both crops. The stress tolerance attributes and plant growth promotion (PGP) indicate the potential of Pseudomonas fluorescens BoGl123 to be used as a microbial inoculant in the cultivation of wheat and maize under stressful conditions.