CLONING ANALYSIS OF CRY1AA GENE OF Bacillus thuringiensis 1FO STRAIN F.B. Kobilov, I.M. Khalilov, M.M. Nazirov, R.A. Alamuratov, N.Sh. Azimova Institute of Microbiology of the Academy of Science of the Republic of Uzbekistan. 7b Abdulla Qadiri Street, Tashkent 100128 It is known that biological agents, in particular, microorganisms, are used in the care
of agricultural crops, fruit and ornamental trees, especially in protecting them from
various pests.
Bacillus thuringiensis bacterium also contains genes encoding many anti-
pest proteins, and screening and research on the genetic characteristics of
B. thuringiensis have been carried out for more than 30 years.
B. thuringiensis (Bt) is an aerobic, spore-forming, gram-positive, and entomopathogenic
bacterium that produces parasporal crystal proteins or δ-endotoxins (Cry).
Based on amino acid sequence similarity, 79 cry gene families (cry1-cry79) with
more than 770 cry genes have been characterized to date. These toxins exhibit strong
toxicity against Lepidoptera, Diptera, Coleoptera, Hymenoptera, Orthoptera, Hemiptera,
and Nematodes, which are considered to be various insect pests. The Cry1Aa gene
encodes the CRY1Aa protein, which is toxic to pests of the Lepidoptera group.
Firstly, genomic DNA was isolated from
B. thuringiensis 1fo strain and specific
primers were designed for screening Cry1Aa gene and PCR amplification was
performed. Cry1Aa fragment was ligated into the vector (4634 bp) and chemically
transformed into
E. coli DH5a strain. Cry1Aa gene ligation was detected by oncolony
PCR from colonies grown on LB agar medium with selective kanamycin (Fig. 1 A).
The resulting colonies were planted in LB (kanamycin) liquid medium. Then, plasmid
DNA was isolated and restricted using
KpNI -
BamHI enzymes (Fig. 1 B).
Figure 1. A-Cry1Aa gene oncolony PCR product, B- Cry1Aa gene restriction analysis:
1-
KpNI and
BamHI , 2-
BamHI , 3-uncut plasmid
Figure 1 shows that the Cry1Aa gene was efficiently cloned, and the PCR and
restriction enzyme products were of the same size as expected for the Cry1Aa gene.
According to the literature that CRY1Aa protein has an active effect on other pests
besides
Helicoverpa armigera and
Helicoverpa zea . For example:
Plutella xylostella insects fed on cabbage and brussels sprouts transformed with Cry1Aa genes were
reported to die 100% within 72 hours.
In conclusion, the cloning of the Cry1Aa gene of
Bacillus thuringiensis is an
important scientific achievement in the field of insect pest control and can be a powerful
tool for sustainable agriculture.
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