Journal of Environmental Biology

Phosphate solubilizing and indole-3-acetic acid producing bacteria from the soil of Garhwal Himalaya aimed to improve the growth of rice 

Yogendra Singh Gusain¹*, Ranveer Kamal¹, C. M. Mehta¹, U. S. Singh² and A.K. Sharma¹

¹Department of Biological Sciences, G.B. Pant University of Agriculture and Technology, Pantnagar-263 145, India

²IRRI NASC Complex, Pusa, New Delhi-110 012, India

*Corresponding Authors Email : ygusain99@gmail.com

Publication Data

Paper received:

10 October 2013

Revised received:

08 March 2014

Accepted:

20 May 2014

Abstract

In the present study, soil bacteria from rainfed agriculture field of Garhwal Himalaya, just prior to sowing of summer crop, were isolated and initially tested for solubilization of inorganic phosphate, production of indole acetic acid (IAA) and siderophore. Two bacterial isolates, having efficient P- solubilizing activity in solid medium, were identified using 16S rRNA sequence analysis as Pseudomonas koreensis strainYB1 Arthrobacter nitroguajacolicus strainYB3 and three bacterial isolates, producing high amount of IAA in liquid medium, were identified as Klebsiella oxytoca strainYB2 and two strain of Arthrobacter nitroguajacolicus, strainYB4 and YB5, respectively. In culture medium supplemented with L-Tryptophan, Klebsiella oxytoca produced high amount of IAA (337.44?g l-1). The selected five bacterial strains were further tested for tricalcium phosphate (TCP) solubilizing abilities at three different incubation temperature viz., 4?C, 10?C and 28?C, under in vitro conditions. At 28?C, three bacterial strains Pseudomonas koreensis, Arthrobacter nitroguajacolicus strainYB4 and Klebsiella oxytoca solubilized the phosphate efficiently. At 10?C only two strains, Pseudomonas koreensis and Arthrobacter nitroguajacolicus strainYB4 solubilized phosphate efficiently as compared to other strains. These five bacterial strains were tested for nitrogen, catalase activity, starch and cellulose hydrolysis as well as growth promotion activity on rice, under controlled conditions. All the five bacterial strains efficiently increased the biomass and phosphorus uptake in Swarna and Swarna sub1 varieties of rice. ??  

 Key words

Indole acetic acid production, Phosphate solubilization, Plant growth promotion 

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