Molecular Underpinnings of Bark Beetle Resistance against Conifer Chemical Defences.

Aisha Naseer

Disertační práce

Abstract:

Eurasian Spruce Bark Beetle (ESBB), Ips typographus (Coleoptera: Scolytinae), is one of the primary forest pests around Europe. They attack the bark and inter-cortical regions of the host, Picea abies, generally, the phloem and growing cambial zone, where the adults feed and reproduce, and the larvae develop. To protect themselves from colonisation, plants use anatomical and chemical defences. However, bark beetles have defence mechanisms to tolerate this harsh environment in their host, which can be attributed to one or more biochemical co-evolutions that allow them to survive in a host defence-rich environment. Such biochemical tolerance mechanisms may be achieved by detoxification of toxic plant compounds or their digestion in the midgut of the beetle by the production of certain enzymes. In invertebrates, many genes, and their enzymes (like P450s, UGTs, GST, AChE, and ABC transporter genes) play a vital role in defending the organism against oxidative stress by regulating many stress-responsive genes and are responsible for the detoxification of plant defence chemicals. Hence, greater knowledge of the function of these genes mentioned above is required to breakdown the molecular mechanism underlying beetle resistance against conifer defences. The presented study focused on how I. typographus efficiently conquered the spruce chemical defences using an omics-based approach. We reported that the genes related to detoxification, digestion, and resistance are critically expressed during host feeding or overexposure to host allelochemicals. We identified key genes, such as, CYP6A2, UGT2B17, ST1B1, GSTT1, and members of ABC gene families and multidrug resistance-associated proteins involved in the detoxification of host chemicals. The presented study provides a catalogue of genes that can be targeted for future I. typographus management that can subsequently be functionally validated by gene silencing via RNA interference (RNAi) or CRISPR/Cas9 mechanism.

Keywords

Ips typographus, Monoterpenes, Detoxification, RNA seq, Norway Spruce, Bark Beetle, RT-qPCR, Enzyme assay

Jazyk práce: angličtina

Datum vytvoření / odevzdání či podání práce: 19. 10. 2024

Obhajoba závěrečné práce

• Vedoucí: Amit Roy, Ph.D.
• Oponent: Petr Doležal, Ing., externi, Fatma Aydinoglu, Ing., externi, Archana Singh, externi

Česká zemědělská univerzita v Praze

Fakulta lesnická a dřevařská

Doktorský studijní program / obor:
Forestry Engineering / Forest Biology