Activities:

1) Molecular plant pathology

The interactions between genetic systems of host (usualy important crops) and their pathogen (bacteria, fugi, parasitic weeds and nematods) is studied.

The current reseach is focused to: Increasing the crop resistance against broomrapes (Orobanche spp.) by identification and manipulation of key genes in biosynthetic pathway of orobanche seed's germination stimulants. The broomrapes (Orobanchaceae) are obligatory root parasites of plants. Currently there are no effective, inexpensive control measures for broomrape that can be applied in case of large scale outbreak. We focus our research on the germination of the parasite seeds, which only occurs when the parasite seed detects the presence of a specific chemical signal(s) (germination stimulants - GS) exuded by the host root. Research is focused on Arabidopsis as a host for Orobanche because of its sequenced genome and readily available mutant populations.

2) Increasing of biological value of crop production

This area of research is a combination between genomic and metabolomic approaches aimed to increase accumulation of "healthy" components and products in important crops

We investigate mutants from sweet pepper that accumulate about twenty times more carotenoids. Several cDNAs of most of the important enzymes converting carotenoids like lycopene beta cyclase, beta carotene hydrolase/hydroxylase, zeaxanthin epoxydase, capsanthin-capsarubin synthase etc. have already isolated. The investigations will also allow to create an EST library of "healthy" and mutant genes from the biosynthetic pathway of the carotenoids.

The plans are to sub-clone the isolated genes in bacterial expression vectors and produce enzymes in order to better study the alteration in enzymatic activities.

There is also interest in application of such construct for production of certain forms of carotenoids in microbial bioreactors or other biotechnology processes.

Recent projects:

Genomics investigations in Orobanche sp. - NSF - Bulgaria

Molecular biology of carotenoids synthesis in sweet pepper - NSF - Bulgaria

Drought tolerance in Bulgarian endemic relict species Haberlea rhodopensis - NSF - Bulgaria

Molecular biology of carotenoids synthesis in sweet pepper - IAEA

Recent publications:

T Gechev, F Van Breusegem, Julie M. Stone, I. Denev and Christophe Laloi, 2006 Reactive oxygen species as signals that modulate plant stress responses and programmed cell death, BioEssays 28:1091–1101

Denev I., Yahoubian G., Minkov I., Sundqvist C., 2005 Light-induced changes of protochlorophyllide oxidoreductase organization in prolamellar bodies, isolated from etiolated carotenoid-deficient wheat plants, revealed by fluorescence probes", BBA-Biomembranes, 1716, 97-103

Denev I., Yahubian G., Minkov I. 2005 Recent advances in chloroplast development in higher plants, In Handbook of Photosynthesis, 2nd edition (Pessarakli M ed.) Marsel Dekker Inc., New York , chapter 18. pp 451-467.

Mishev K., Denev I., Radeva G., Ananiev E. D. 2006, RNA transcription in isolated chloroplasts during senescence and rejuvenation of intact cotyledons of Cucurbita  pepo L.  (Zucchini), Compt Rend Bulg Acad Sci – Biologie (Physiologie des plantes) , 59, 1287 – 1292.

Denev I., Yahubyan G., and Stefanov D. (2005), Synthesis of chlorophyll in leaves of Haberlea rhodopensis (Friv.) during prolonged darkening. Compt Rend Bulg Acad Sci –Biologie (Physiologie des plantes) , 58, 1429 – 1432.

Staff involved: