Isolation and characterization of deleterious Pseudomonas aeruginosa KC1 from rhizospheric soils and its interaction with weed seedlings

The bacterial isolate KC1 was screened from the rhizosphere of castor plants (Ricinus communis) indigenous to agricultural fields of Bihar. The isolate was Gram negative, non-spore forming, and exhibited fluorescence under UV light. Its molecular characterization is based on the sequencing of 16S rDNA (1450 bp) and alignment at GeneBank (NCBI, MaryLand). The strain has been validated as Pseudomonas aeruginosa (HM195190). The bacterium grew at 4–42 °C, with a temperature optima of 30 °C. The strain KC1 was found to produce cyanide (4.78 nmol l−1) over a period of 36 h. Data revealed enhanced cyanogenesis (6.98 nmol l−1), when glycine was provided in the King’s B medium. Seed bacterization exhibited reduction in root length, shoot length of weed seedlings (Amaranthus spinosus, Portulaca oleracea), which was significant (p < 0.05) in both laboratory and glasshouse experiments. Biomass was significantly reduced (p < 0.05) for the weed seedlings in glasshouse experiments. However, KC1 inoculated crop seedlings (Triticum aestivum) were found to be less inhibitory as compared to weed seedlings. The observations are significant to establish, that the secondary metabolites producing KC1 rhizobacterium, P. aeruginosa KC1 could be exploited as a weed biocontrol agent. The innate potential of KC1 could be further formulated and utilized in field applications for agricultural sustainability.