Drought-Adapted Rhizospheric Leucobacter komagatae from Sugarcane: First Report and Functional Profiling as a Biofertilizer Candidate
摘要
Agriculture productivity worldwide is significantly impacted by drought stress, which is expected to become more prevalent. To address water stress, various adaptation and mitigation approaches are necessary. Plant growth promoting rhizobacteria (PGPR) show promise for enhancing plant growth in water-scarce environments. In this context, we isolated 68 morphologically different bacterial strains from the rhizosphere of drought tolerant as well as normal sugarcane crop. Drought tolerance of these strains was assessed using a growth medium with polyethylene glycol (PEG-6000) concentrations ranging from 5–35% L−1. Morphological characterization and resilience to elevated temperatures (45 °C) of these isolates were also examined. Twelve robust strains that endured both high temperature and stress were subsequently evaluated for their phytohormone producing capabilities. Out of twelve, four potential strains viz., ASBD 2, 15, 19 & 30 showed efficient plant growth promoting traits as these strains produced IAA (28.94, 31.54, 27.42, & 30.06 µg/ml), Phosphate solubilization (26.17, 24.57, 29.91, & 20.69 µg/ml), zinc solubilization (26.17, 24.57, 29.91, & 20.69 µg/ml), sulfur ions oxidation (1.95, 2.16, 1.77, & 2.03 mg ml−1), gibberellic acid production (2.61, 1.99, 2.13, & 2.01 ng/ml), and siderophore production (82.4, 76.77, 70.98 & 80.12 psu) respectively. 16S rRNA gene sequencing identified these four strains as Leucobacter komagatae from drought tolerant sugarcane varieties CoLK 15466 and CoLK 94184. These outcomes suggest that the drought resistant PGPR L. komagatae could potentially enhance plant growth and development under water-scarce conditions. To the best of our knowledge, this is the first report of isolating L. komagatae from drought-tolerant sugarcane, as well as its in vitro PGPR assessment.