Plants and insects coevolved as an evolutionarily successful and enduring association. The molecular arms race led to evolutionary novelties regarding unique mechanisms of defence and detoxification in plants and insects. While insects adopt mechanisms to conquer host defence, trees develop well-orchestrated and species-specific defence strategies against insect herbivory. However, current knowledge on the molecular underpinnings of fine-tuned tree defence responses against different herbivore insects is still restricted. In the current study, using a multi-omics approach, we unveiled the defence response of Populus tremula against aphids (Chaitophorus populialbae) and spongy moths (Lymantria dispar) herbivory. Comparative differential gene expression (DGE) analyses revealed that around 272 and 1203 transcripts were differentially regulated in P. tremula after moth and aphid herbivory compared to uninfested controls. Interestingly, 5716 transcripts were differentially regulated in P. tremula between aphids and moth infestation. Further investigation showed that defence-related stress hormones and their lipid precursors, transcription factors, and signalling molecules were over-expressed, whereas the growth-related counterparts were suppressed in P. tremula after aphid and moth herbivory. Metabolomics analysis documented that around 37% of all significantly abundant metabolites were associated with biochemical pathways related to tree growth and defence. However, the metabolic profiles of aphid and moth-fed trees were quite distinct, indicating species-specific response optimization. After identifying the suitable reference genes in P. tremula, the omics data were further validated using RT-qPCR. Nevertheless, our findings documented species-specific fine-tuning of the defence response of P. tremula, showing conservation on resource allocation for defence overgrowth under aphid and moth herbivory. Such findings can be exploited to enhance our current understanding of molecular orchestration of tree responses against herbivory and aid in developing insect pest resistance P. tremula varieties.

• Klíčová slova
• Populus tremula, RT-qPCR, aphids, induced defence, reference gene analysis, spongy moth, transcriptome and metabolomics,
• MeSH
• býložravci * MeSH
• metabolom MeSH
• metabolomika metody   MeSH
• mšice * fyziologie   MeSH
• můry * fyziologie   genetika   MeSH
• Populus * genetika   parazitologie   metabolismus   MeSH
• regulace genové exprese u rostlin * MeSH
• stanovení celkové genové exprese MeSH
• transkriptom * MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

Global warming is predicted to change the growth conditions for plants and crops in regions at high latitudes (>60° N), including the Arctic. This will be accompanied by alterations in the composition of natural plant and pest communities, as herbivorous arthropods will invade these regions as well. Interactions between previously non-overlapping species may occur and cause new challenges to herbivore attack. However, plants growing at high latitudes experience less herbivory compared to plants grown at lower latitudes. We hypothesize that this finding is due to a gradient of constitutive chemical defense towards the Northern regions. We further hypothesize that higher level of defensive compounds is mediated by higher level of the defense-related phytohormone jasmonate. Because its biosynthesis is light dependent, Arctic summer day light conditions can promote jasmonate accumulation and, hence, downstream physiological responses. A pilot study with bilberry (Vaccinium myrtillus) plants grown under different light regimes supports the hypothesis.

• Klíčová slova
• climate change, jasmonate signaling, light regime, pest distribution, plant defense,
• Publikační typ
• časopisecké články MeSH

Several studies have shown that insectivorous birds are attracted to herbivore-damaged trees even when they cannot see or smell the actual herbivores or their feces. However, it often remained an open question whether birds are attracted by herbivore-induced changes in leaf odor or in leaf light reflectance or by both types of changes. Our study addressed this question by investigating the response of great tits (Parus major) and blue tits (Cyanistes caeruleus) to Scots pine (Pinus sylvestris) damaged by pine sawfly larvae (Diprion pini). We released the birds individually to a study booth, where they were simultaneously offered a systemically herbivore-induced and a noninfested control pine branch. In the first experiment, the birds could see the branches, but could not smell them, because each branch was kept inside a transparent, airtight cylinder. In the second experiment, the birds could smell the branches, but could not see them, because each branch was placed inside a nontransparent cylinder with a mesh lid. The results show that the birds were more attracted to the herbivore-induced branch in both experiments. Hence, either type of the tested cues, the herbivore-induced visual plant cue alone as well as the olfactory cues per se, is attractive to the birds.

• Klíčová slova
• herbivory, olfaction, systemic induction, vision, volatile organic compounds,
• Publikační typ
• časopisecké články MeSH

The present review summarises current knowledge of phytoecdysteroids' biosynthesis, distribution within plants, biological importance and relations to plant hormones. Plant ecdysteroids (phytoecdysteroids) are natural polyhydroxylated compounds that have a four-ringed skeleton, usually composed of either 27 carbon atoms or 28-29 carbon atoms (biosynthetically derived from cholesterol or other plant sterols, respectively). Their physiological roles in plants have not yet been confirmed and their occurrence is not universal. Nevertheless, they are present at high concentrations in various plant species, including commonly consumed vegetables, and have a broad spectrum of pharmacological and medicinal properties in mammals, including hepatoprotective and hypoglycaemic effects, and anabolic effects on skeletal muscle, without androgenic side-effects. Furthermore, phytoecdysteroids can enhance stress resistance by promoting vitality and enhancing physical performance; thus, they are considered adaptogens. This review summarises current knowledge of phytoecdysteroids' biosynthesis, distribution within plants, biological importance and relations to plant hormones.

• Klíčová slova
• 20-Hydroxyecdysone, Ecdysteroids, Phytoecdysteroids, Plant hormones, Signalling molecules,
• MeSH
• ekdysteroidy biosyntéza   MeSH
• regulátory růstu rostlin metabolismus   MeSH
• rostliny metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH
• Názvy látek
• ekdysteroidy MeSH
• regulátory růstu rostlin MeSH