Journal of Microbiology

Research Support, Non-U.S. Gov'ts

Impact of cry1AC-Carrying Brassica rapa subsp. pekinensis on Leaf Bacterial Community: Young Tae Kim , Kang Seon Lee , Moon Jung Kim , Seung Bum Kim; J. Microbiol. 2009;47(1):33-39. Published online February 20, 2009; DOI: https://doi.org/10.1007/s12275-008-0254-4

Abstract: The effects of Chinese cabbage (Brassica rapa subsp. pekinensis) carrying cry1AC derived from Bacillus thuringiensis (Bt) on leaf bacterial community were examined by analyzing the horizontal transfer of transgene fragments from plants to bacteria. The effect of plant pathogenic bacteria on the gene transfer was also examined using Pseudomonas syringae pathovar. maculicola. The frequency of hygromycin-resistant bacteria did not alter in Bt leaves, though slight increase was observed in Pseudomonas-infected Bt leaves with no statistical significance. The analysis of bacterial community profiles using the denaturing gradient gel electrophoresis (DGGE) fingerprinting indicated that there were slight differences between Bt and control Chinese cabbage, and also that infected tissues were dominated by P. syringae pv. maculicola. However, the cultured bacterial pools were not found to contain any transgene fragments. Thus, no direct evidence of immediate gene transfer from plant to bacteria or acquisition of hygromycin resistance could be observed. Still, long-term monitoring on the possibility of gene transfer is necessary to correctly assess the environmental effects of the Bt crop on bacteria.

Expression of a Recombinant Cry1Ac Crystal Protein Fused with a Green Fluorescent Protein in Bacillus thuringiensis subsp. kurstaki Cry-B: Jong Yul Roh , In Hee Lee , Ming Shun Li , Jin Hee Chang , Jae Young Choi , Kyung Saeng Boo , Yeon Ho Je; J. Microbiol. 2004;42(4):340-345.; DOI: https://doi.org/2101 [pii]

Abstract: To investigate the co-expression and crystallization of a fusion gene between the Bacillus thuringiensis crystal protein and a foreign protein in B. thuringiensis, the expression of the Cry1Ac fused with green fluorescent protein (GFP) genes in a B. thuringiensis Cry-B strain was examined. The cry1Ac gene was cloned in the B. thuringiensis-E. coli shuttle vector, pHT3101, under the control of the native cry1Ac gene promoter, while the GFP gene was inserted into the XhoI site upstream of the proteolytic cleavage site, in the middle region of the cry1Ac gene (pProAc-GFP). The B. thuringiensis Cry-B strain carrying pProAc-GFP (ProAc-GFP/CB) did not produce any inclusion bodies. However, the transformed strain expressed fusion protein forms although the expression level was relatively low. Furthermore, an immunoblot analysis using GFP and Cry1Ac antibodies showed that the fusion protein was not a single species, but rather multiple forms. In addition, the N-terminal fragment of Cry1Ac and a non-fused GFP were also found in the B. thuringiensis Cry-B strain after autolysis. The sporulated cells before autolysis and the spore-crystal mixture after autolysis of ProAc-GFP/CB exhibited insecticidal activities against Plutella xylostella larvae. Accordingly, the current results suggest that a fusion crystal protein produced by the transfomant, ProAc-GFP/CB, can be functionally expressed but easily degraded in B. thuringiensis.

Denaturing Gradient Gel Electrophoresis Analysis of Bacterial Community Profiles in the Rhizosphere of cry1AC-carrying Brassica rapa subsp. pekinensis: Sera Jung , Semi Park , Daeha Kim , Seung Bum Kim; J. Microbiol. 2008;46(1):12-15.; DOI: https://doi.org/10.1007/s12275-007-0190-8

Abstract: The effect of genetically modified (GM) Brassica rapa subsp. pekinensis (Chinese cabbage) expressing Bt toxin gene (cry1AC) to the rhizosphere bacterial community was examined using the denaturing gradient gel electrophoresis (DGGE) fingerprinting method. From the visual comparison of the DGGE profiles, there were no significant differences between the profiles of Bt and control rhizosphere in both Suwon and Yesan samples. From the sequence analysis of the individual bands, Sphingomonas sp. of Alphaproteobacteria and several actinobacterial members were identified as the main bacterial taxa in both Suwon and Yesan samples. In the multiple correspondence analysis, no clear separation between Bt and control rhizosphere was seen in both Suwon and Yesan datasets. The profiles of bulk soils were separated from those of rhizosphere. The DGGE fingerprinting analyses indicated that Bt crops did not significantly alter the genetic composition of rhizosphere bacterial communities.

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