Castor (Ricinus communis L.) is a primary food plant of eri silkworm, Samia ricini Donovan endemic to Northeast India. Plant growth promoting rhizobacteria (PGPR) plays crucial role in growth and productivity of agricultural crops. Eighty-five Pseudomonas strains were isolated from thirty rhizosphere soil samples of castor and their in vitro potentiality was screened for growth promoting ability and antifungal potentialities. Most of the selected Pseudomonas sp. produced indole acetic acid, gibberellic acid, ACC deaminase activity, ammonia, hydrogen cyanide and siderophore, when tested in-vitro for PGP activity. Besides, the strains MAJ PIA01, MAJ PIA03 and MAJ PIA24 have got antifungal activity against five common plant pathogens. Upon their formulation and application in field by curtailing the recommended dose of inorganic fertilizers to 50 %, isolate no. MAJ PIA03 efficiently enhanced the agronomical traits such as number of leaves per plant, leaf biomass, root length, stem base diameter, shoot length, root biomass and leaf moisture content. Isolate no. MAJ PIA03 has significant impact on leaf biochemical constituents and augments the nutritional quality of castor leaf. The most efficient isolate MAJ PIA03 was identified as Pseudomonas aeruginosa MAJ PIA03 by polyphasic approach and its 16S rRNA gene homology. The bio-formulation of Pseudomonas aeruginosa MAJ PIA03 with 50 % diminution on recommended inorganic NPK dose could be used as an effective mechanism to improve Ricinus communis plant growth as well as leaf nutritional enhancement for sustainable eri sericulture.