Aravanopoulos, F. A. | bioRxiv Science

bioRxiv2025

Genomic signatures of climate-driven (mal)adaptation in an iconic conifer, the English yew (Taxus baccata L.)

The risk of climate maladaptation is increasing for numerous species, including trees. Developing robust methods to assess population maladaptation remains a critical challenge. Genomic offset approaches aim to predict climate maladaptation by characterising the genomic changes required for populations to maintain their fitness under changing climates. In this study, we assessed the risk of climate maladaptation in European populations of English yew (Taxus baccata), a long-lived tree with a patchy distribution across Europe, the Atlas Mountains, and the Near East, where many populations are small or threatened. We found evidence suggesting local climate adaptation by analysing 8,616 SNPs in 475 trees from 29 European T. baccata populations, with climate explaining 18.1% of genetic variance and 100 unlinked climate-associated loci identified via genotype- environment association (GEA). Then, we evaluated the deviation of populations from the overall gene-climate association to assess variability in local adaptation or different adaptation trajectories across populations and found the highest deviations in low latitude populations. Moreover, we predicted genomic offsets and successfully validated these predictions using fitness proxies assessed in plants from 26 populations grown in a comparative experiment. Finally, we integrated information from current local adaptation, genomic offset, historical genetic differentiation and effective migration rates to show that Mediterranean and high-elevation T. baccata populations face higher vulnerability to climate change than low-elevation Atlantic and continental populations. Our study demonstrates the practical use of the genomic offset framework in conservation genetics, offers insights for its further development, and highlights the need for a population-centred approach that incorporates additional statistics and data sources to credibly assess climate vulnerability in wild plant populations.

genomics↗

bioRxiv2025

Genetic, epigenetic and metabolite variation in peripheral European Yew (Taxus baccata L.) populations at an unexplored part of the species natural distribution

Taxanes form effective anticancer agents, which are found in the leaves and barks of the yew tree (Taxus L.). Taxol(R) (also known as paclitaxel), 10-diacetylbacatin III, 10-deacetyltaxol III, baccatin III and cephalommanine are anti-neoplastic taxanes used for cancer treatment. Due to the high demand of taxanes, it is of great pharmaceutical interest to investigate unexplored to date population diversity. In this context, three peripheral Greek Taxus baccata L. populations (Mt Cholomon, Mt Olympus and Mt Vourinos) were investigated to identify the extent and structure of their genetic (based on microsatellite markers), epigenetic (based on methylation sensitive amplified markers) and chemodiversity (based on liquid chromatography mass spectrometry) profiles. Results showed that the concentration of taxanes varied considerably in relation to population and harvest season. The main taxane in T. baccata needles was 10-deacetylbacatin III (DAB), with concentrations ranging from 267.8 (Mt Vourinos) to 517.6 (Mt Olympus) mg kg-1 dw. Besides metabolite variation, notable levels of genetic diversity and significant population differentiation were revealed. These results, in conjunction to the high levels of total methylation found in all populations, indicate their potential adaptability under climatic change. The findings of this study pave the way for prospective breeding and conservation strategies of these important Taxus baccata L. populations for artificial selection of highly producing taxane trees and protection of local germplasm.

plant biology↗