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University of Agricultural Sciences, Dharwad

The University of Agricultural Sciences, Dharwad was established on October 1, 1986. The University has 5 Colleges, 27 Research Stations, 6 Agriculture Extension Education Centers, 6 Krishi Vigyan Kendras and ATIC. The University has its jurisdiction over 7 districts namely Bagalkot, Belgaum, Bijapur, Dharwad, Gadag, Haveri, and Uttar Kannada in northern Karnataka. Greater diversity exists in soil types, climate, topography cropping and farming situations. The jurisdiction includes dry-farming to heavy rainfall and irrigated area. Important crops of the region include sorghum, cotton, rice, pulses, chilli, sugarcane, groundnut, sunflower, wheat, safflower etc. The region is also known for many horticultural crops. Considerable progress has been registered in the field of education, research and extension from this University.

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20111
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Subject: Agricultural Microbiology × Type: Thesis × Thesis Type: Ph.D × Author: Ashwini B.K. ×
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    ThesisItemOpen Access
    Molecular Characterization and Insecticidal Activity of Bacillus tluringiensis Isolates, Cloning and Expression of cry, vip Gene Variants and Mutagenesis of Codon Optimized cry1 Ac
    (UAS Dharwad, 2011) Ashwini B.K.; P.U. Krishnaraj
    The present work involved isolation of B. thuringiensis from different ecological niches, followed by their molecular characterization, cloning and expression of variants of cry and vip and mutagenesis of cry. From a total of 1745 soil samples collected, 977 isolates were identified as B. thuringiensis. The most predominant crystalline inclusion was the spherical crystals. The presence of cry/vip genes was determined and the most abundant gene was cry10 and cry 20. Several isolates had more than one cry gene in them. Only ten of the isolates harboured vip3A. Four isolates showed 100 per cent mortality at 48h of exposure against third instar larvae of Plutella xylostella. Twenty two native isolates exhibited 100 per cent mortality at72h. The per cent mortality of third instar larvae of Crocidolomia binotalis ranged from 0 to 100 per cent. The reference strain HD1 exhibited 96.6 per cent mortality, whereas the isolate DBT 763 exhibited 100 per cent mortality. The analysis of rep PCR fingerprints showed 18 to 20 bands with size ranging from 0.2 to 5kb with ERIC2 primer alone. One of the isolates DBT1881 showed 100 per cent similarity to B. thuringiensis subsp. andalousiensis where as DBT1853 showed 100 per cent similarity to three of the B. thuringiensis serovars viz, aizawai, toumanoffi and roskildiensi. The variant cry1 gene from DBT381 and DBT84 based on ARLP patterns was cloned and expressed in E. coli. The nucleotide sequence showed 99 per cent homology with the reference cry1Ac22 (EU282379.1). The vip3A variant was cloned from 4L3 and 4C2 and was expressed in E. coli. The codon optimized cry 1Ac from the truncated version (1.85kb) of a native cry1Ac was subjected to random mutagenesis and one mutant RM2G was observed to possess 20 per cent more toxicity than the cry1AcM to P. xylostella.