I am a plant pathologist and a 3rd year PhD candidate. During my PhD project I study the different functions of glycoside hydrolases family 18 (GH18) in filamentous fungi. This family includes enzymes with chitinolytic activity (chitinases) and enzymes with deglycosylation role (ENGases). Chitinases play important roles in fungal biology, e.g. in growth and morphological development, in nutrient acquisition and in aggressive interactions.
The availability of fungal genome sequence information has shown that the diversity of the fungal GH18 gene family is larger than previously thought. My study is concentrated on understanding the function of chitinases in different aspects of fungal lifecycle and especially the role of these enzymes in fungal – fungal interactions, in model species (Neurospora crassa, Aspergillus nidulans) and in mycoparasites (Clonostachys rosea IK726) generating deletion strains, coupled with expression studies using quantitative PCR. We focus our studies in chitinases that show similarities with the α-subunit of the yeast killer toxin produced by Kluyveromyces lactis, and they are therefore hypothesized to be involved in antagonistic interactions with other fungi.
Furthermore, we study the functional role of ENGases in filamentous fungi. These enzymes are involved in Endoplasmic Reticulum Associated Degradation (ERAD) process of misfolded proteins in mammalian and plant cells. The existence of this pathway in fungal cells is under investigation. In this project, which is conducted in collaboration with Glycometabolome team in RIKEN Advanced Institute, we try to quantify the amount of free oligosaccharides in fungal cytoplasm using liquid chromatography (HPLC), helping us to understand the functional role of ENGases in filamentous fungi.
List of Publications
- Tzelepis G. D., Melin P, Jensen D. F, Stenlid J. and Karlsson M. 2012. Functional analysis of glycoside hydrolase family 18 and 20 genes in Neurospora crassa. Fungal Genetics and Biology. 49: 717-730.
- Bardas G.A., Tzelepis G.D., Lotos L. and Karaoglanidis G.S. 2009. First report of Botrytis cinerea causing gray mold of pomegranate (Punica granatum) in Greece. Plant Disease 93: pp1346
- Bardas G.A., Tzelepis G.D., Lotos L. and Karaoglanidis G.S. 2009. First report of Penicillium glabrum causing fruit rot of pomegranate (Punica granatum) in Greece. Plant Disease 93: pp1347
- Tzelepis G. D., Melin P, Jensen D. F, Stenlid J. and Karlsson M. (2012). Functional analysis of glycoside hydrolase family 18 genes in Neurospora crassa. 11th European Conference on Fungal Genetics. 30 March – 2 April 2012. Marburg, Germany.
- Tzelepis G.D., Melin P., Stenlid J., Jensen D.F. and Karlsson M (2011). Phenotypic analysis of Neurospora crassa chitinase knockout mutants reveals the potential role of cht-12 in hyphal growth. 26th Fungal Genetics Conference. 15- 21 March. Asilomar, CA, USA. 15 – 20 March 2011.
Colony morphology of N. crassa wild type (WT) and intracellular ENGase deletion strain in different growth media