Whole Genome Analysis of Sugarcane Root-Associated Endophyte Pseudomonas aeruginosa B18—A Plant Growth-Promoting Bacterium With Antagonistic Potential Against Sporisorium scitamineum

Sugarcane smut is a significant fungal disease that causes a major loss in sugar yield and quality. In this study, we isolated an endophytic strain B18 from a sugarcane root, which showed plant growth-promotion, hydrolytic enzyme production, antifungal activity against sugarcane pathogens ( Sporisorium scitamineum, Ceratocystis paradoxa, Fusarium verticillioides ), and the presence of nifH , acdS , and antibiotic genes ( hcn, prn , and phCA ) under in vitro conditions. BIOLOG (R) phenotypic profiling of B18 established its ability to use various carbon and nitrogen sources and tolerate a range of pH and osmotic and temperature stresses. Whole-genome analysis of B18, identified as Pseudomonas aeruginosa , showed that it consists of a single circular chromosome of 6,490,014 bp with 66.33% GC content. Genome annotation has identified 5,919 protein-coding genes, and 65 tRNA, and 12 rRNA genes. The P. aeruginosa B18 genome encodes genes related to ethylene, nitrogen ( nifU , norBCDERQ , gltBDPS , and aatJMPQ ), and phosphate ( pstABCS and phoBDHRU ) metabolism and produce indole-3-acetic acid and siderophores. This also includes genes encoding hydrolases and oxidoreductases, those associated with biocontrol mechanisms ( hcnABC , phzA_B , phzDEFGMS , and pchA ), colonization ( minCDE and lysC ), and biofilm formation ( efp , hfq , flgBCDEFGHI , and motAB ), and those associated with metabolism of secondary metabolites. Collectively, these results suggest a role for P. aeruginosa B18 in plant growth enhancement and biocontrol mechanisms. The P. aeruginosa B18 strain was found to be an efficient colonizer in sugarcane; it can improve growth through modulation of plant hormone production and enhanced host-plant resistance to smut pathogen S. scitamineum in a smut-susceptible sugarcane variety (Yacheng71-374). These biocontrol and plant growth promotion properties of P. aeruginosa B18 area are discussed in this report.