Exploring rhizobacteria of wild sugarcane (Saccharum spontaneum L.) and their plant growth promoting potential

In this study, the rhizospheric soil of wild sugarcane from three different salt-affected soils of the eastern Indo-Gangetic Plains was sampled. Rhizospheric bacteria from S. spontaneum were isolated and they were characterized for growth-promoting traits with molecular identification. A total of 49 isolates were isolated from three S. spontaneum rhizosphere soils from different places. These isolates were shown to have differential tolerance to NaCl concentrations up to 2000 mM. Owing to their host habitat and poor nutrient availability, these bacteria were found to have excellent tolerance to high NaCl concentrations along with having multiple plant growth traits. Apart from salt tolerance, these isolates were screened for EPS production, phosphate solubilization, zinc solubilization, siderophore production and ammonia production and based on multiple plant growth-promoting traits, twenty isolates were taken for molecular identification and further in vivo screening. These twenty S. spontaneum rhizospheric microbes belonged to the classes Gammaproteobacteria, Firmicutes (Bacilli) and Actinomycetia, representing six genera and 15 species. In vivo growth promotion studies indicated that some of these isolates could improve germination and growth in rice seedlings. The results of this study signify the possibility of utilizing wild crop microbiomes to nurture cultivated crops under adverse growing conditions.