Root Associated Bacterial Endophytes From Poaceae Plants: Identification, Characterization and Plant Growth Promotion

Abstract

Diazotrophic endophytic bacteria contribute to the plant growth using various plant growth promoting traits as well as by inducing the plant defence mechanism upon pathogen attack. Aim of the present study was to isolate true diazotrophic endophytic bacteria from the total diazotrophic bacterial community of wheat and pearl-millet plants. Further, these isolates were evaluated for their potential of plant growth promotion by in vitro and in vivo experiments. We isolated total three diazotrophic endophytic bacteria based on their growth after repetitive subculturing on nitrogen free medium. Molecular characterization of all three isolates showed affiliation to the genera Agrobacterium, Pseudomonas and Brevundimonas. In vitro analysis of plant growth promoting traits showed positive result for indole acetic acid (IAA) production, cellulase and protease activity. The IAA production is found between the ranges of 98 to 113 µg ml-1. All the endophytic bacterial isolates showed the PCR amplification of NifH gene and ammonia production. Diazotrophic endophytic bacterial isolates (PR1, JB3 and JB6) were tested for their capacity to promote the plant growth using pot experiment. All the diazotrophic endophytic bacteria differ in their plant growth promotion ability as analyzed by various plant growth parameter compared to the untreated control plants. In Pot experiment, PR1 and JB6 showed a significant difference in dry weight of root, whereas JB3 and JB6 showed the significant differences in shoot length and total nitrogen content (p≤0.05) compared to the untreated plants.

An exopolysaccharide-producing novel Agrobacterium pusense strain JAS1 isolated from snake plant enhances plant growth and soil water retention

“…The species Agrobacterium pusense (AP), first isolated from chickpea rhizosphere (NRCPB10 T ) 30 , initially sat within the genus Rhizobium but was later shifted to Agrobacterium based on housekeeping DNA barcodes 31 , 32 . Newer AP strains have increasingly been reported recently, of which only a few were studied for their PGP assets 33 – 44 .…”