Pantnagar Journal of Research

Abstract

Endophytic bacteria improve plant growth through diverse biochemical and metabolic activities that involve enhancement of nutrient availability, phytohormone production, and stress tolerance. In the present study, 5 endophytic bacteria from the leave of Kasni (Cichorium intybus) were isolated and evaluated for their invitro plant growth promoting (PGP) potential. The isolates were qualitatively evaluated for nutrient (phosphate) solubilization, siderophore ammonia, biofilm, Indole 3 acetic acid (IAA) and antioxidants production. During qualitative analysis, only 3 isolates demonstrated positive results and were further quantified for their PGP and antioxidants activities. The maximum concentration of IAA was produced by the isolate KSBP2 in tryptic soy broth (TSB) (170.13±0.7 µg/mL) followed by KSBP1 (61.15±0.7) at 96 h of incubation. The isolate was also found positive for gibberellic acid, salicylic acid, siderophore production and phosphate solubilization. The antioxidant potential of isolates were evaluated by quantifying total phenolics and flavonoid contents. The isolate KSBP2 showed maximum total phenolics (2.81±0.02 mg GAE/g) and flavonoids (0.18±0.01mg QE/g) contents in ethyl acetate extract. Furthermore, the isolate KSBP2 was assessed for biochemical and molecular characterization. Molecular characterization of KSBP2 based on 16S rRNA gene sequence analysis demonstrated 99.7% similarity of the isolate with Bacillus velezensis. Overall, the endophytic isolate KSBP2 possesses multiple plant growth promoting and antioxidant potential which might be a promising approach towards the enhancement of plant growth and development through improved nutrient availability and phytohormone production.