Potential of PGPRS for Managing Bacterial Wilt Disease and to Enhance Growth and Biochemical Attributes of Tomato

Pathogenic stress causes severe cellular damage and leads to plant diseases. Hydrogen cyanide (HCN)-producing plant growth-promoting rhizobacteria (PGPR) may help to manage disease and significantly improve plant growth and physiological attributes in arid and semiarid environments. This study aimed to evaluate PGPRs against pathogen Ralstonia solanacearum (the real cause of bacterial wilt disease) as biocontrol agents and their role in improving tomato (Solanum lycopersicum) yield during 2023. Twenty PGPR strains were isolated from the root rhizosphere and assessed for plant growth-promoting traits i.e. indole-3-acetic acid (IAA), phosphate, potassium and zinc solubilization, as well as HCN and siderophore production. Seven PGPR strains were analyzed using 16S rRNA gene sequencing. The disc sensitivity technique was used to evaluate PGPRs against R. solanacearum under laboratory conditions with three replicates. Completely Randomized Design (CRD) was used to evaluate the PGPRs under greenhouse conditions with 3 replicates (5 plants per replicate). Pseudomonas aeruginosa was the most effective strain, inhibiting pathogen growth by 56% and reducing disease incidence. PGPR-treated tomato seedlings showed improvement in plant growth through increased plant height, root, shoot length and fruit production. HCN-producing PGPR (P. aeruginosa and Bacillus megaterium) enhanced plant immunity by increasing superoxide dismutase, peroxidase, and catalase enzyme levels. Mineral nutrition improved through enhanced solubilization of potassium, phosphorus and zinc under biotic stress. HCN-producing PGPRs enhance tomato yield by improving nutrient availability and inducing plant defense mechanisms. These findings highlight their potential as biocontrol agents for sustainable tomato production in arid and semiarid regions.