Isolation and Molecular Characterization of Potential Plant Growth PromotingBacillus cereusGGBSTD1 andPseudomonasspp. GGBSTD3 from Vermisources
Vermicompost was prepared from leaf materials ofGliricidia sepium+Cassia auriculata+Leucaena leucocephalawith cow dung (1 : 1 : 2) usingEudrilus eugeniae(Kinberg) andEisenia fetidafor 60 days. Nineteen bacterial strains which have the capability to fix nitrogen, solubilize inorganic phosphate, and produce phytohormones were isolated from vermicompost, vermisources, and earthworm (fore, mid, and hind) guts and tested for plant growth studies. Among the bacterial strains only five strains had both activities; among the fiveBacillusspp. showed more nitrogen fixing activity andPseudomonasspp. showed more phosphate solubilizing activity. Hence these bacterial strains were selected for further molecular analysis and identifiedBacillus cereusGGBSTD1 andPseudomonasspp. GGBSTD3. Plant growth studies use these two organisms separately and as consortium (Bacillus cereus+Pseudomonasspp.) in (1 : 1) ratio at different concentrations usingVigna unguiculata(L.) Walp. at different day intervals. The germination percent, shoot length, root length, leaf area, chlorophyll a content of the leaves, chlorophyll b content of the leaves, total chlorophyll content of the leaves, fresh weight of the whole plant, and dry weight of the whole plant were significantly enhanced by the consortium (Bacillus cereus+Pseudomonasspp.) of two organisms at 5 mL concentrations on the 15th day compared to others.