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Published on: August 20, 2018
[Effect of quorum sensing response regulator nprR deletion on expression of cry protein in Bacillus thuringiensis]
1State Key Laboratory for Biology of Plant Diseases and Insect Pest, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China. wangyao18@hotmail.com
Objective:
The role of Quroum Sensing response regulator nprR on the expression of Cry protein in B. thuringiensis HD-73 was studied.
Methods:
The nprR gene deletion mutant HD73 (delta nprR) was constructed by using of homologous recombination. Beta-galactosidase assay of cry1Ac'-lacZ gene fusion and SDS-PAGE in both HD-73 and HD73 (delta nprR) strains were performed to analyze the effect of nprR gene deletion on expression of cry1lAc gene.
Results:
Beta-galactosidase assay of nprR'-lacZ in both LB and Schaeffer' s sporulation medium showed nprR gene in B. thuringiensis was initially transcripted at TO (end of Logarithmic growth phase) and keeping expression in stationary phase. Beta-galactosidase assay of cry1Ac'-lacZ and SDS-PAGE indicated that expression of cry1Ac gene in HD73 (delta nprR) was stronger than that in HD-73 during transition phase and early stationary phase. However, Cry expressed product between HD-73 and HD73 (delta nprR) in LB medium has no significant difference when crystal and spore were released.
Conclusion:
The deletion of nprR increased expression and transcription activity of cry1Ac during transition and early stationary phase in rich media.
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