Molecular
characterization of chitinase producing
Bacillus
thuringiensis
P.
Singh1, A. Joshi1, D.J. Nath2, A. Gayan3,
S. Sanadhaya1, H. Saheewala1, P. Jain1, L.
Gupta4, S.R. Mohanty5 and D. Jain1*
1Department of
Molecular Biology and Biotechnology, RCA, Maharana Pratap University of
Agriculture and Technology, Udaipur-313 001, India
2Department of Soil
Science, Assam Agricultural University, Jorhat-785 013, India
3College of
Sericulture, Soil Science, Assam Agricultural University, Jorhat-785 013,
India
4Department of
Animal Production, RCA, Maharana Pratap University of Agriculture and
Technology, Udaipur-313 001, India
5All India Network
Project on Soil Biodiversity and Bio-fertilizers, ICAR-Indian Institute of
Soil Science, Bhopal-462 038, India
*Corresponding
Author Email : devendrajain@mpuat.ac.in
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Abstract
Aim:
In the present study, twenty eight Bacillus thuringiensis (Bt) strains
were studied for their potential to hydrolyze chitin.
Methodology: The chitinolytic potential of Bt strains were
determined using modified chitinase screening media (CSM) containing
colloidal chitin as substrate. The potential Bt strains were screened for the
presence of cry genes using PCR and further molecular characterized using 16S
rDNA amplification and sequencing.
Results:
Among 28 Bt strains, 10 strains showed positive results by producing clear
halo zone around bacterial colonies and the maximum chitinase solubilization
index was observed in Bt-13 whereas the minimum solubilization index was
observed in Bt-27 strain. Further, the chitinase assay revealed the minimum
enzyme activity in Bt-26 (3.78 ± 0.101 U ml-1) whereas the maximum
activity was observed in strain Bt-2 (10.19 ± 0.651 U ml-1). PCR
based chitinase gene screening also revealed the presence of both
endochitinase and exochitinase genes in these Bt strains. The potent Bt
strains viz., Bt-7, Bt-10, Bt-11, Bt-13 and Bt-27 on the basis of chitinase
production were molecular characterized based on 16S rDNA and sequencing
results reveled their greatest sequence identity Bacillus thuringiensis.
Interpretation: Results showed that the high chitinase
activity of these Bt strains may be due to the presence of chitinase genes,
which need to be explored for further biological applications.
Key words: Bacillus thuringiensis, Chitinase, Molecular
characterization, PCR
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