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

Terrestrial orchids can form tubers, organs modified to store energy reserves. Tubers are an attractive source of nutrients, and salep, a flour made from dried orchid tubers, is the source of traditional beverages. Tubers also contain valuable secondary metabolites and are used in traditional medicine. The extensive harvest of wild orchids is endangering their populations in nature; however, orchids can be cultivated and tubers mass-produced. This work illustrates the importance of plant-fungus interaction in shaping the content of orchid tubers in vitro. Orchid plants of Dactylorhiza sp. grown in asymbiotic culture were inoculated with a fungal isolate from Tulasnella calospora group and, after 3 months of co-cultivation, tubers were analyzed. The fungus adopted the saprotrophic mode of life, but no visible differences in the morphology and biomass of the tubers were detected compared to the mock-treated plants. To elucidate the mechanisms protecting the tubers against fungal infestation, proteome, metabolome, and lipidome of tubers were analyzed. In total, 1,526, 174, and 108 proteins, metabolites, and lipids were quantified, respectively, providing a detailed snapshot of the molecular process underlying plant-microbe interaction. The observed changes at the molecular level showed that the tubers of inoculated plants accumulated significantly higher amounts of antifungal compounds, including phenolics, alkaloid Calystegine B2, and dihydrophenanthrenes. The promoted antimicrobial effects were validated by observing transient inhibition of Phytophthora cactorum growth. The integration of omics data highlighted the promotion of flavonoid biosynthesis, the increase in the formation of lipid droplets and associated production of oxylipins, and the accumulation of auxin in response to T. calospora. Taken together, these results provide the first insights into the molecular mechanisms of defense priming in orchid tubers and highlight the possible use of fungal interactors in biotechnology for the production of orchid secondary metabolites.

• Klíčová slova
• biotic interaction, defense priming, lipidome, metabolome, orchid tuber, proteome,
• Publikační typ
• časopisecké články MeSH