Hazelnut genome and transcriptome analysis under biotic and abiotic stress

Official URL: https://risc01.sabanciuniv.edu/record=b2553602 _(Table of contents)

European hazel (Corylus avellana L.) is a crop tree of well-known health benefits and great economic importance, but only limited number of studies exist about it at the molecular level. The aim of this thesis to demonstrate the mechanisms of genes under biotic and abiotic stresses, and analysis of the cv ‘Tombul’ genome, one of the most important Turkish varieties. Firstly, the emerging powdery mildew pathogen, Erysiphe corylacearum, and the degree of genetic diversity within the growing epidemic were analyzed with DNA barcode analysis and molecular markers. No genetic variation was observed within these samples, suggesting that the current outbreak originated from a single recent transmission event. In order to utilize available hazelnut genetic resources for crop improvement, annotation for cv Tombul was carried through a fully assembled genome sequence produced with a hybrid sequencing strategy. The genome includes 27,270 high-confidence protein-coding genes, over 20,000 of which were functionally annotated based on homology to known plant proteins. Furthermore, the complete chloroplast genome was assembled and analyzed with multiple annotation tools, having a typical quadripartite structure. This can provide comprehensive genetic insight into the evolution of genus Corylus. Lastly, transcriptome analysis was conducted to obtain new insight on the genes and gene networks involved in chilling stress. A total of 2,440 differentially expressed transcripts were generated, and of these, 1,368 were upregulated under chilling stress. It may facilitate further study on freezing tolerance mechanisms which could be useful for breeding approaches in tree species.