Protease and Phytohormone Production by Potassium solubilizers Isolated from Maize Rhizosphere

Enzymes and phytohormones are essential substances required for plant development, especially at their vegetative stage.Microbial-plant-root interactions on rhizosphere region make possible for both nutrient mineralization and absorption.An in-vitro assessment was carried out to assess the protease, indole acetic and gibberellic acids production patterns by Lysinibacillus fusiformis and Providencia rettgeri.Both bacterial strains produced indole acetic and gibberellic acids; two essential phytohormones necessary for seed germination and fruit ripening.Time of incubation of both bacterial inoculants had significant effects (p<0.05) on protease activities.Lysinibacillus fusiformis produced more protease (0.6630±0.003 µg/mL) at 96 h after incubation, while the highest protease activity by Providencia rettgeri was observed at 72 h after incubation with a mean value of 0.4605±0.004µg/mL.However, Lysinibacillus fusiformis produced more protease enzyme compared to Providencia rettgeri.The production trends of gibberellic and indole acetic acids were also study.The amount of gibberellic acid produced changed significantly (p<0.05) with time.The activity of gibberellic acid was at its peak 48 h after incubation for both Lysinibacillus fusiformis (76.25±0.21µg/mL) and Providencia rettgeri (151.85±0.78µg/mL), with Providencia rettgeri producing more gibberellic acid than Lysinibacillus fusiformis.The highest production of IAA was at its peak at 72 h after incubation for Lysinibacillus fusiformis (1.4530±0.001µg/mL) but was not significantly (p>0.05)different with change in time.Providencia rettgeri produced more IAA at 72 h of incubation (1.1450±0.004µg/mL) and was significantly (p<0.05)different with change in time.