Effect of endophytic bacterial consortium isolated from tea (Camellia sinensis (L.) O. Kuntze) roots on growth and yield of Phaseolus vulgaris L.

Abstract

This paper deals with the isolation of endophytic bacteria from roots of tea (Camellia sinensis (L.) O. Kuntze) shrubs of upper Assam, India, and evaluates their potential for promoting plant growth in-vitro. Out of forty bacterial isolates, Bacillus cereus, Bacillus flexus, Pseudomonas sp., and Pseudomonas rhodesiae were most effective in mineral solubilization and plant growth-promoting hormone production. Pseudomonas sp. showed the highest indole acetic acid (IAA, 16.75 ± 0.04 μg/m) production, gibberellic acid (GA3, 4.12± 0.11 μg/ml) production, and potassium solubilization index (2.70 ± 0.05). Bacillus cereus was the highest phosphate (174.33±2.0 μg/ml) and zinc solubilizer (solubilization index 2.35± 0.01and 2.53 ±0.02 for ZnO and ZnS respectively). Siderophore activity was the highest in P. rhodesiae (87.37 ± 0.73%). All the isolates mentioned above were active against test plant pathogens Alternaria sp., Rhizoctonia solani, Sclerotinia sclerotiorum, and Fusarium solani. Inoculation of Bacillus cereus, Bacillus flexus, Pseudomonas sp., and Pseudomonas rhodesiae to the soil in pot culture of Phaseolus vulgaris showed significant promotion of plant growth and yield.