Activities:

The group is established as a Laboratory of Genetic Engineering and Plant Biotechnology to the Department of Plant Physiology and Molecular Biology an University of Plovdiv " Paisii Hilendarski" (and to the Genomic Research Center) and comprises a fully equipment unit capable to perform all standard molecular biology manipulations.

Mode of action of cry proteins and insect resistance in transgenic plant

Bacillus thuringiensis is an economically important Gram-positive bacterium widely used for insect control of many insect pests belonging to insect orders Lepidoptera, Coleoptera, and Diptera. The main B. thuringiensis related research is focused on the knowledge-based improvement of insecticidal properties and widening the insecticidal spectrum of Cry toxins via protein engineering, and construction of novel hybrid cry genes. Studying the mode of action of non-typically organized delta-endotoxins, and development of Colorado potato beetle pest resistant management strategies are our recent priorities.

As a result of collaboration with Plant Research International BV, Wageningen, The Netherlands, a unique cry1 hybrid gene (SN19) is created and based on it the first in world transgenic potato plants with engineered resistance against coleopterans and lepidopterans, by expression of a single gene were obtained. Additionally in collaboration with Michigan State University the potency of SN19 against Cry3Aa resistant Colorado potato beetle larvae was proven.

Hepatitis B "core" protein based edible vaccines

Plant based edible vaccines may provide an attractive, safe and inexpensive alternative to conventional vaccine production. DNA transformed plants can produce foreign antigens from common infectious organisms. Productions of vaccines in plants could have significant advantage over current methods. The work is a part of the cooperation program with Dr. Anton Andonov from Canadian Science Center for Human and Animal Health, Winnipeg, Canada. An effective expression system for immunogenic protein HBc from Hepatitis B virus and WHc from Woodchuck Hepatitis virus in transgenic potato and tobacco plants has been created.

The approach is based on expression of recombinant HBV and WHV capsids protein. The capsid proteins can self-assemble into naturally shaped virus-like particles (VLP), which are non-infectious and can be used as universal carriers for vaccine production. It was found that the expression in potato and tobacco plants results in self-assembly of HBV/WHV VLPs. There is a long term interest in edible vaccines based on HBV/WHV

nucleocapsid proteins as carriers of foreign epitopes.

Recent projects:

Transformation of potato plants with the core-protein from Hepatitis B virus- NSF – Bulgaria

BT genes and BT toxins, GMO and non-GMO approach - NSF - Bulgaria

TRNSCONTAINER – STREP, FP6

Recent publications:

R. Boncheva; St. Dukiandjiev, I. Minkov, R. deMaagd, and S. Naimov Activity of Bacillus thuringiensis delta-endotoxins against codling moth (Cydia pomonella L.) larvae Journal of Invertebrate  Pathology 2006 92: 84-87

Samir Naimov, Gergana Zahmanova, Rumyana Boncheva, Milena Kostova, Ivan Minkov, Stefan Dukiandjiev, and

Ruud A. deMaagd. Expression of synthetic SN19 gene in transgenic potato. Biotechnology and biotechnology

equipment 2006 3: 38-41

R. Boncheva, St. Dukiandjiev, I. Minkov, R. deMaagd, and S. Naimov Activity of

Bacillus thuringiensis delta-endotoxins against codling moth (Cydia pomonella L.) larvae. Journal of Invertebrate Pathology 2006 92: 84-87

S. Naimov, E. Martens-Uzunova,1 M. Weemen-Hendriks, St. Dukiandjiev, I. Minkov, and R A. de Maagd. Carboxy-Terminal Extension Effects on Crystal Formation and Insecticidal Properties of Colorado Potato Beetle-Active Bacillus thuringiensis δ-Endotoxins Molecular biotechnology 2006 32: 185-196

R. Karlova, M Weemen-Hendriks, S. Naimov, J. Ceron, S. Dukiandjiev and R. de Maagd. Bacillus thuringiensis δ-endotoxin Cry1Ac domain III enhances activity against Heliothis virescens in some, but not all Cry1-Cry1Ac hybrids. Journal of Invertebrate Pathology. 2005 88 (2): 169-172

de Maagd, R.,A., Weemen-Hendriks, M., Molthoff J.,W., and Naimov, S. Activity of wild-type and hybrid Bacillus thuringiensis delta-endotoxins agains Agrotis ipsilon. Arch Microbiol. 2003 179: 363-367

Naimov S., Dukiandjiev St., and de Maagd R. A hybrid Bacillus thuringiensis delta-endotoxin gives resistance against a coleopteran and a lepidopteran pest in transgenic potato. Plant Biotechnology Journal. 2003 1 (1): 51-59 Naimov S., Weemen-Hendriks M. Dukiandjiev St., de Maagd R.,A. Bacillus thuringiensis delta-endotoxin Cry1 hybrid proteins with increased ac tivity against the Colorado potato beetle. Appl Environ Microbiol. 2001 67(11): 5328-5330.

M. Kosrova, A. Linev, S. Naimov, S. Dukiandjiev, R. de Maagd and I. Minkov. Bacillus thuringiensis: cry-genes diversity in Bulgarian strain collection. Proceedings of fifth national scientific conference with international participation - ECOLOGY AND HEALTH May 2004, pages 373-378.

S. Naimov, G. Zahmanova, R. Boncheva, M. Kostova, I. Minkov, S. Dukiandjiev, and R. A. de Maagd. Expression of synthetic SN19 gene in transgenic potato. Biotechnology and biotechnology equipment 2006, 3 p.38-41

G. Zahmanova, V. Radeva, S. Dukiandjiev, I. Minkov and A. Andonov; Edible vaccine against hepatitis B virus. Day of virology in Bulgaria 09/2004 BioTechnology Technological Equipment 3/2004/18 Supplement p.40; Abstract

Staff involved:

Name Position Main research interest
Dr. Samir NaimovResearch group leaderBt-genes, Bt toxins, GMO
Dr. Rumyana BonchevaAssistant ProfessorBt-genes, Bt toxins, B. thuringiensis strains
Milena KostovaResearcherBt-genes, Bt toxins, B. thuringiensis strains
Gergana ZahmanovaResearcherEdible vaccines, Hepatitis B virus