DOIONLINE

DOIONLINE NO - IJASEAT-IRAJ-DOIONLNE-8770

Publish In
International Journal of Advances in Science, Engineering and Technology(IJASEAT)-IJASEAT
Journal Home
Volume Issue
Issue
Volume-5, Issue-3  ( Jul, 2017 )
Paper Title
Isolation and Characterization of Indole-3-Acetic Acid producing Bacterial Root Endophytes Associated with Brown Arson (Brassica Rapa L.)
Author Name
Shahid Ahmad Padder, Zahoor Ahmad Bhat, Kuldeep
Affilition
division of plant pathology, division of soil science skuast-k, deptt. of microbiology, ccs, hau hisar
Pages
69-74
Abstract
In the present study a total of 81 bacterial root endophytes were isolated and screened for IAA production in Luria Bertani broth without supplementation of L-tryptophan and only 54.3% (44 isolates) produced IAA with the overall average production of 8.15 μg/mL. The seventeen isolates exhibiting IAA production of ≥ 9 μg/mL were optimized using Ltryptophan supplementations at different concentrations and incubation periods. Study on various concentrations of Ltryptophan viz. 0.05, 010, 0.15, 0.20 and 0.25 mg/mL on indole-3-acetic acid production revealed maximum IAA production (32.41 μg/mL) at 0.20 mg/mL L-tryptophan concentration and lowest IAA production of 16.21 μg/mL at 0.05 mg/mL concentration. All the isolates followed almost the similar trend with maximum production at 0.2 mg L-tryptophan/mL except the isolates SB41 and SB61 in where peak IAA production occurred at 0.15 mg/mL L-tryptophan concentration. Highest IAA was produced by the isolate SB28 (62.92 μg/mL) at 0.2 mg L-tryptophan/mL and lowest by SB19 (11.10 μg/mL) at 0.05 mg L-tryptophan/mL. The effect of incubation period viz. 48, 96 and 144 h also affected IAA production by bacterial root endophytes. The averag e highest IAA production of 28.80 μg/mL was at incubation period of 96 hour and lowest average production of 19.99 μg/mL was observed at 48 hour incubation. All the 44 isolates producing IAA were identified by amplifying their 16s rRNA genes and observed to be different species of Bacillus, Pseudomonas,Curvibacter, Comamonas, Microbacterium, Arthrobacter, Pantoea,Okibacterium, Salinivibrio, Paenibacillus. Keywords - IAA, tryptophan, incubation period, Pseudomonas, Bacillus
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