Isolation, characterization, and evaluation of multi-trait plant growth promoting rhizobacteria for their growth promoting and disease suppressing effects on ginger

Abstract

In this study, 100 PGPR strains isolated from different varieties of ginger (Zingiber officinale Rosc.) were first characterized for their morphological, biochemical, and nutrient mobilization traits in vitro. The PGPR were also screened in vitro for inhibition of Pythium myriotylum causing soft rot in ginger. Results revealed that only five PGPR showed >70% suppression of P. myriotylum. These 5 PGPR viz., GRB (Ginger rhizobacteria) 25--Burkholderia cepacia, GRB35--Bacillus amyloliquefaciens; GRB58--Serratia marcescens; GRB68--S. marcescens; GRB91--Pseudomonas aeruginosa were used for further growth promotion and biocontrol studies in the green house and field. The green house study revealed that GRB35 (B. amyloliquefaciens) and GRB68 (S. marcescens) registered markedly higher sprouting (96.3%) and lower disease incidence (48.1%) and greater rhizome yield (365.6 g pot(-1) and 384.4 g pot(-1), respectively), while control registered the lowest sprouting (66%), maximum soft rot incidence (100%) and lowest rhizome yield (134.4 g pot(-1)). In the field experiments also, GRB68 (S. marcescens) and GRB35 (B. amyloliquefaciens) registered the greatest sprouting (80% each), markedly lower soft rot incidence (5.2% and 7.3%, respectively) and higher yield (5.0 and 4.3 kg(3)m(-2), respectively) compared to chemicals like Streptomycin sulphate (73.0%, 18.5% and 2.3 kg(3)m(-2), respectively), Metalaxyl-Mancozeb (73.0%, 14.0% and 3.8 kg(3)m(-2), respectively) and control (73.0%, 25.1% and 2.2 kg 3m(-2), respectively). Overall, the results suggested that for growth promotion and management of soft rot disease in ginger, GRB35 B. amyloliquefaciens and GRB68 S. marcescens could be good alternatives to chemical measures. Since, the latter has been reported to be an opportunistic human pathogen, we recommend the use of B. amyloliquefaciens for integration into nutrient and disease management schedules for ginger cultivation.

In Vitro Efficacy of Bacterial Endophytes against Pythium sp. Causing Soft Rot of Ginger in Meghalaya

“…The ability of the bacterial endophytes to suppress the growth of the pathogen maybe reflected to their ability to produced hydrolytic enzyme responsible for the degradation of the pathogen cell wall. The present findings is supported by Dinesh et al, (2015) who reported that isolate Bacillus GRB35 amyloliquefaciens exhibited 78.51% inhibition in growth of P. myriotylum in ginger.…”

Growth and Nutrient Uptake of Orchardgrass (Dactylis glomerata L.) and Meadow Fescue (Festuca pratensis Huds.) as Affected by Rhizobacteria

“…Increases in growth and yield of crops in response to inoculation with PGPR have been repeatedly reported (Baris et al, 2014;Dinesh et al, 2015;Imran et al, 2015;Saia et al, 2015). PGPR exert positive effect on plant growth by direct mechanisms, such as biological N2 fixation, phosphate solubilisation and production of growth regulators (phytohormones), or by indirect mechanisms, such as prevention of the deleterious effects of plant pathogens, production of inhibitory substances (siderophore, antibiotics), or increase of natural resistance of the host (Glick, 1995).…”

Microbial‐Enhanced Phytoremediation of Lead Contaminated Calcareous Soil by Centaurea cyanus L

“…The plates were incubated at 28 °C for three days. Finally, the population of PGPR was determined as number of CFU g −1 soil …”