This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Reprints and Permissions Copyright Information Books from ASM Press MicrobeWorld Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Srinivas, G. Articles by Sekar, V. Search for Related Content PubMed PubMed Citation Articles by Srinivas, G. Articles by Sekar, V. Agricola Articles by Srinivas, G. Articles by Sekar, V.

 Previous Article  |  Next Article 

Appl. Environ. Microbiol., 07 1997, 2792-2797, Vol 63, No. 7
Copyright © 1997, American Society for Microbiology

Unique regulation of crystal protein production in Bacillus thuringiensis subsp. yunnanensis is mediated by the cry protein- encoding 103-megadalton plasmid

G Srinivas, SJ Vennison, SN Sudha, P Balasubramanian and V Sekar
Department of Molecular Microbiology, School of Biotechnology, Madurai Kamaraj University, India.

In sporulating cultures of Bacillus thuringiensis subsp. yunnanensis HD977, two cell types are observed: cells forming only spores and cells forming only crystals. Curing analysis suggested that the crystal proteins are plasmid encoded. Through plasmid transfer experiments, it was established that a 103-MDa plasmid is involved in the crystal production. Conjugal transfer of this plasmid to Cry- recipient cells of Bacillus thuringiensis subsp. kurstaki HD73-26 conferred the ability to produce crystals exclusively on asporogenous cells of the recipient, indicating that the 103-MDa plasmid mediates the unique regulation of Cry protein production. When the dipteran-specific cryIVB gene was introduced into wild-type (Cry+) and Cry- backgrounds of B. thuringiensis subsp. yunnanensis by phage CP51ts45-mediated transduction, similar to all other B. thuringiensis strains, irregular crystals of CryIVB protein were produced by spore-forming cells in both backgrounds. However, the synthesis of the bipyramidal inclusions of B. thuringiensis subsp. yunnanensis was still limited only to asporogenous cells of the transductant. Thus, it appears that the unique property of exclusive crystal formation in asporogenous cells of B. thuringiensis subsp. yunnanensis is associated with the crystal protein gene(s) per se or its cis acting elements. As the crystals in B. thuringiensis subsp. yunnanensis were formed only in asporogenous cells, attempts were made to find out whether crystal formation had any inhibitory effect on sporulation. It was observed that both Cry+ and Cry- strains of B. thuringiensis subsp. yunnanensis (HD977 and HD977-1, respectively) exhibited comparable sporulation efficiencies. In addition, the Cry- B. thuringiensis subsp. kurstaki host (HD73-26) and its Cry+ transconjugant (HD73-26-16), expressing the B. thuringiensis subsp. yunnanensis crystal protein, were also comparable in their sporulation efficiencies, indicating that production of the crystal proteins of B. thuringiensis subsp. yunnanensis does not affect the process of sporulation.

This article has been cited by other articles:

• Balasubramanian, P., Jayakumar, R., Shambharkar, P., Unnamalai, N., Pandian, S. K., Kumaraswami, N. S., Ilangovan, R., Sekar, V. (2002). Cloning and Characterization of the Crystal Protein-Encoding Gene of Bacillus thuringiensis subsp. yunnanensis. Appl. Environ. Microbiol. 68: 408-411 [Abstract] [Full Text]