Identification and Characterization of Desiccation-Tolerant Cyanobacteria from Pokhran, India for Their Potential Application as Biofertilizer

The present study was conducted to isolate, identify, and characterize cyanobacteria from the desert areas of Pokhran, Rajasthan, India. Ten cyanobacterial isolates, viz., Anabaena sp. (SGR4 and SGR7), Nostoc sp. (SGR1, SGR3, and SGR11), Neowestielliopsis sp. (SGR8), Calothrix sp. (SGR5 and SGR10), Fischerella sp. (SGR16), and Hapalosiphon sp. (SGR2) able to grow at various desiccation levels (polyethylene glycol, 3–10% wt/vol) were identified based on their morphological and molecular characteristics. It was further observed that the isolates SGR2, SGR3, SGR7, SGR8, and SGR16 grew optimally at higher concentrations of polyethylene glycol (10% wt/vol). The isolate SGR8, identified as Neowestielliopsis sp., showed a high growth rate (215.0 ± 30.72 µg mL^–1), ammonia release (66.07 ± 2.25 µg mL^–1), indole acetic acid production (77.71 ± 2.36 µg mL^–1), nitrogenase activity (7.22 ± 0.26 µmol C₂H₄ mg Chl^–1), and exopolysaccharide production (148.63 ± 11.85 µg mL^–1). The isolates, viz., SGR2, SGR3, SGR7, and SGR16, also showed differential growth rates and plant growth promoting traits. Moreover, all the isolates showed greater activity of superoxide dismutase, ascorbate peroxidase, and catalase. Inoculation with the cyanobacterial strain SGR8 (Neowestiellopsis sp.) improved the plant height, dry weight accumulation, and chlorophyll content of wheat plants. Based on the outcomes, cyanobacterial isolates may be used as biofertilizer in the mitigation of desiccation stress in plants.