Assessment of Plant Growth-Promoting Parameters of Endophytes Isolated from Calotropis procera and Their Performance Under Irrigated and Non-irrigated Conditions

In the present study, bacterial and fungal endophytes are isolated from Calotropis procera , a drought-resistant plant and studied for their role in plant growth promotion. Among bacterial sp. Enterobacter cloacae subsp. cloacae strain CPR5B and fungus, Penicillium citrinum strain CPL1F, were identified as potent endophytes as both strains were able to produce Indole Acetic Acid (IAA) and 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase and solubilize phosphate. Penicillium citrinum CPL1F also been shown to produce siderophore. The IAA production was observed to be 94.28 μg/mL and 17.1 μg/mL for bacterial and fungal sp., respectively. The phosphate solubilization was observed to be 76.41 μg/mL and 114.57 μg/mL, respectively. The in vitro plant treatment studies with bacterium and fungus under irrigated and non-irrigated conditions showed that both strains had promoted plant growth in both conditions with respect to their control. Both the strains showed significant changes in most of the growth parameters under endophyte-treated irrigated and non-irrigated conditions, suggesting their stress-dependent plant growth promotion. The present findings will contribute to exploring endophytes that enhance plant growth in adverse conditions and act as plant growth-promoting endophytes.