Climate change has increased the susceptibility of forest ecosystems, resulting in escalated forest decline globally. As one of the largest forest biomasses in the Northern Hemisphere, the Eurasian boreal forests are subjected to frequent drought, windthrow, and high-temperature disturbances. Over the last century, bark beetle outbreaks have emerged as a major biotic threat to these forests, resulting in extensive tree mortality. Despite implementing various management strategies to mitigate the bark beetle populations and reduce tree mortality, none have been effective. Moreover, altered disturbance regimes due to changing climate have facilitated the success of bark beetle attacks with shorter and multivoltine life cycles, consequently inciting more frequent bark beetle-caused tree mortality. This review explores bark beetle population dynamics in the context of climate change, forest stand dynamics, and various forest management strategies. Additionally, it examines recent advancements like remote sensing and canine detection of infested trees and focuses on cutting-edge molecular approaches including RNAi-nanoparticle complexes, RNAi-symbiotic microbes, sterile insect technique, and CRISPR/Cas9-based methods. These diverse novel strategies have the potential to effectively address the challenges associated with managing bark beetles and improving forest health in response to the changing climate.

Since the development of next-generation sequencing techniques and with the growing interest in transcriptomic studies, there is a demand for high-throughput RNA extraction techniques. General RNA extraction protocols are unreliable when it comes to the quality and quantity of isolated RNA obtained from different tissue types of different plant species. Despite Norway spruce (Picea abies) being one of the most significant and commercially valuable tree species in European forests, only limited genetic research is available. In this study, we developed a cetyltrimethylammonium bromide (CTAB) protocol by modifying the original method. We compared this CTAB protocol with other widely used methods for extracting RNA from different tissues (needle, phloem, and root) of Norway spruce, known for its richness in polyphenols, polysaccharides, and secondary metabolites. The modified CTAB method proves to be superior to the kit-based and TRIzol-based methods for extracting RNA from the metabolite-rich tissues of Norway spruce, resulting in high RNA quality and integrity values (RIN~7–9). The modified CTAB RNA extraction method is rapid, cost-effective, and relatively simple in yielding the desired RNA quality from Norway spruce tissues. It is optimal for RNA sequencing and other downstream molecular applications.

Journal of Simulation (JOS) publishes articles, technical notes, case studies and tutorials in the field of simulation, with a particular focus on the applications of simulation and modelling. Journal of Simulation is an official journal of the OR Society.

Plant defence mechanisms, including physical barriers like toughened bark and chemical defences like allelochemicals, are essential for protecting them against pests. Trees allocate non-structural carbohydrates (NSCs) to produce secondary metabolites like monoterpenes, which increase during biotic stress to fend off pests like the Eurasian spruce bark beetle, ESBB (Ips typographus). Despite these defences, the ESBB infests Norway spruce, causing significant ecological damage by exploiting weakened trees and using pheromones for aggregation. However, the mechanism of sensing and resistance towards host allelochemicals in ESBB is poorly understood. We hypothesised that the exposure of ESBB to spruce allelochemicals, especially monoterpenes, leads to an upsurge in the important detoxification genes like P450s, GSTs, UGTs, and transporters, and at the same time, genes responsible for development must be compromised. The current study demonstrates that exposure to monoterpenes like R-limonene and sabiene effectively elevated detoxification enzyme activities. The differential gene expression (DGE) analysis revealed 294 differentially expressed (DE) detoxification genes in response to R-limonene and 426 DE detoxification genes in response to sabiene treatments, with 209 common genes between the treatments. Amongst these, genes from the cytochrome P450 family 4 and 6 genes (CP4 and CP6), esterases, glutathione S-transferases family 1 (GSTT1), UDP-glucuronosyltransferase 2B genes (UDB), and glucose synthesis-related dehydrogenases were highly upregulated. We further validated 19 genes using RT-qPCR. Additionally, we observed similar high expression levels of detoxification genes across different monoterpene treatments, including myrcene and α-pinene, suggesting a conserved detoxification mechanism in ESBB, which demands further investigation. These findings highlight the potential for molecular target-based beetle management strategies targeting these key detoxification genes.