Disentangling pheromone biosynthesis in European spruce bark beetle (Ips typographus; Coleoptera; Scolytinae)

Rajarajan Ramakrishnan, MSc

Disertační práce

Abstract:

The European spruce bark beetle, Ips typographus is a key pest among spruce forests across the many Eurasian regions including the Czech Republic. Host trees colonization by Ips typographus is mediated by aggregation pheromone blend, consisting of 2-methyl-3-buten-2-ol and cis-verbenol synthesized from the beetle gut. The molecular trait of pheromone biosynthesis research in I. typographus has not been conducted yet in detail. In this research, our primary focus is to reveal the molecular level changes relevant to pheromone biosynthesis across the bark beetle life stages. Followed by an artificial hormonal treatment, by applying juvenile hormone III (JH III), highlighting the key pathway mechanism using sophisticated multi-omics approaches. By co-relating the quantified key aggregation pheromones and respective biosynthetic gene expressions, the respective gene candidates were identified and proposed. A novel hemiterpene-synthesizing candidate isoprenoid-di-phosphate synthase (IPDS) from the mevalonate pathway, proposed for 2-methyl-3-buten-2-ol synthesis was significantly expressed in the pheromone-producing beetles. Other putative gene families such as cytochrome P450 (CYP450) for cis/trans-verbenol synthesis, an esterase gene family for (concept of cis-verbenol storage), and glycosyl hydrolase gene family for releasing pheromone cis-verbenol by breaking down the conjugates were covered in this research. Findings from the pheromone biosynthesis research on Ips typographus are the first such reported results with related gene families. The identified genes can support for developing novel strategies to disrupt the aggregation behavior of Ips typographus and contribute for future eco-friendly management of this devasting pest.

Keywords

Ips typographus, bark beetle, pheromone biosynthesis, multi-omics.

Jazyk práce: angličtina

Datum vytvoření / odevzdání či podání práce: 21. 10. 2024

Obhajoba závěrečné práce

• Vedoucí: Ing. Anna Jirošová, Ph.D.
• Oponent: Irena Valterová, CSc., prof. RNDr., Iva Pichová, externi, Christer Löfstedt, externi

Česká zemědělská univerzita v Praze

Fakulta lesnická a dřevařská

Doktorský studijní program / obor:
Forestry Engineering / Forest Biology