Characterization of plant growth-promoting rhizobacterium Exiguobacterium NII-0906 for its growth promotion of cowpea (Vigna unguiculata)

Abstract

A phosphate solubilizing and antagonistic bacterial strain, isolated from a Western Ghat forest soil in Kerala province, India (designated as NII-0906), showed cold tolerance and grew from 10 to 37It was a Gram-positive, rod shaped, 0.8-1.6 µm in size, and exhibited tolerance to a wide pH range (5-12; optimum 7.0) and salt concentration up to 7% (w/v). The isolate showed maximum similarity with Exiguobacterium marinum TF-80 T based on 16S rRNA analysis. It solubilized tricalcium phosphate under in vitro conditions. The phosphate solubilization was estimated along a temperature range (5-40• C), and maximum activity (84.7 µg mL −1 day −1 ) was recorded at 30• C after 10 days of incubation. The phosphate solubilizing activity coincided with a concomitant decrease in pH of the medium. The isolate also exhibited antifungal activity against phytopathogenic fungi in Petri dish assays and produced siderophore and hydrogen cyanide. The strain's plant growth promotion properties were demonstrated through a cowpea-based bioassay under greenhouse conditions. The bacterial inoculation resulted in significant increment in plant root, stem and as well as in plant biomass. Further, scanning electron microscopic study revealed the root colonization in cowpea. These results could offer potential perspective for the strain to be used as plant growth-promoting rhizobacteria, which could be used as an inoculant for regional crops.

Isolation and Characterization of Highly Effective Phytate-Mineralizing Klebsiella pneumonia Strain MK1C Adapted to Arid and Semiarid Conditions from Calcareous Soil

“…Further future studies are needed to answer such questions. This is an agreement with other the solubilization of P was due to the production of organic acids (Dastager et al, 2010;Pandey et al, 2006), siderophore (Sharma et al, 2013), indole acetic acids (Sergeeva et al, 2007), phytase (Acu?a and Jorquera, 2011;Konietzny and Greiner, 2004), and protons during ammonia respiration Ramesh et al, 2014;Reyes et al, 2006).…”

Improvement of Growth, Yield, and Pigmentation of Mung Bean Plants UsingOchrobactrum intermediumCP‐2 as Bioinoculant

“…In‐planta, studies have shown the enhancement of shoot and root lengths and weights in plants bacterized with the test strain as compared to uninoculated ones. Many reports have described the significant increase in root length and root weight in wheat , maize , cowpea , cucumber , and mung bean in pot and field experiments. In the present study, the percent increase in shoots was more at 15 DAS as compared to 65 DAS with a few exceptions which showed that the effect was steeper in initial stages, although it remained significant even at harvest.…”

Novel plant growth promoting rhizobacteria—Prospects and potential

“…Phosphate solubilizing Exiguobacterium strains were isolated from acidic soils of Argentina (Collavino et al, 2010) and paddy fields of Eastern Uttar Pradesh in India (Kumar et al, 2010). Phosphate solubilizing and antagonistic Exiguobacterium strains isolated from Western Ghats of India are reported to increase growth and biomass of cowpea under green house conditions (Dastager et al, 2010). The presence of Exiguobacterium was also observed in the root nodules of fenugreek (Trigonella foenum-graecum) by Rajendran et al (2012).…”