3th WCSET-2014 at Nepal
Applied Sciences Session:
Title:
Isolation and Characterization of Endophytic
Diazotrophic Bacteria Isolated from Croton sparciflorous
for Indole Acetic Acid Production
Authors:
Abha Singh, Swapnil Singh, Sushma Kumari, V. Lakshmi,
Chander Prabha
Abstract:
Endophytic diazotrophic bacteria promote plant growth
through different mechanisms including biological
nitrogen fixation (BNF), solubilization of minerals and
production of phytohormone: indole 3-acetic acid (IAA).
This study was done to isolate and characterize the
endophytic diazotrophic bacteria from Croton
sparciflorous. A total of six endophytic diazotrophs
were isolated from roots and stems of the host weed,
which were further screened for nitrogen fixation and
IAA production. One of the selected root isolate namely,
ENB1 was gram negative, non spore forming rod, which
exhibited highest nitrogenase activity (1.41nmol mg-1
protein h -1 ) and IAA production (241.86 µg ml-1 ). The
amounts of indole produced were 260µg ml-1 and 280 µg
ml-1 at optimum pH 6 and temperature 30°C, respectively.
Regarding the effect of substrate (L-Tryptophan)
concentrations, 1.0 g L -1 of tryptophan level gave
maximum indole production (284µg ml-1). Its molecular
characterization is based on the sequencing of 16S rDNA
and phylogenetic analysis, which identified the strain
as Agrobacterium tumefaciens ENB1. The present study
indicates that the strain ENB1 seems to be an efficient
plant growth promoting bacteria and it could serve as an
excellent candidate to be used as biofertilizer.
Keywords: Croton
sparciflorous, endophytes, diazotrophs, IAA,
L-tryptophan, 16S rDNA sequencing, biofertilizer
Pages:
635-642