Abstract
Abstract
Fungal phytopathogens and soil salinity pose a severe threat to global agriculture by drastically reducing crop yield and quality. In this study, a multifunctional, halotolerant plant growth-promoting rhizobacterium (PGPR) was isolated from the rhizosphere of
Plantago ovata
and identified as
Cytobacillus oceanisediminis
strain PP10 using 16S rRNA gene sequencing. In dual culture antagonism assays, strain PP10 exhibited antifungal activity, inhibiting
Fusarium
sp. mycelial growth by 60%. Quantitative and qualitative characterization demonstrated plant growth-promoting (PGP) traits, including the production of indole-3-acetic acid (IAA), gibberellic acid (GA), ammonia, exopolysaccharides (EPS), hydrolytic enzymes, and phosphate solubilization. Strain PP10 demonstrated halotolerance, sustaining active growth at salinity levels up to 13% (w/v) NaCl. Comprehensive secretome profiling using Liquid chromatography – mass spectrometry (LC-MS) and Gas chromatography – mass spectrometry (GC-MS) identified an array of bioactive secondary metabolites and antifungal volatiles, notably pyrrolnitrin, 2,4-di-tert-butylphenol, rhamnolipids, 2-piperidinone, desferrioxamine A1, palmitic acid, and stearic acid.
In vivo
pot trials with
P. ovata
demonstrated that PP10 bacterization significantly enhanced seed germination, root/shoot vigor, and biomass accumulation. Collectively, these findings present the first report of
Cytobacillus oceanisediminis
PP10 as a novel bacterium showing plant growth promoting traits that significantly enhanced vegetative growth in
P. ovata
, demonstrating its potential as a biofertilizer for sustainable agriculture.