Biology subjects

Sperisen, C.

Publications and source records attributed to Sperisen, C..

3 recordsLinked to original sources

bioRxiv2022

Tracing the origin of Oriental beech stands across Western Europe and reporting hybridization with European beech - implications for assisted gene flow

Human-aided translocation of individuals within the species range, assisted gene flow (AGF), has been suggested as a climate change mitigation strategy, especially for foundational species, such as forest trees. The benefits and risks of AGF largely depend on the genetic divergence between host and donor populations, their rate and direction of hybridization, and the climate distance that the transfer involves. In this study, we explored the use of Oriental beech (Fagus sylvatica subsp. orientalis), growing from Iran to the Balkans, for AGF in populations of European beech (F. sylvatica subsp. sylvatica), which grow throughout Europe and are increasingly affected by climate warming. Using 16 microsatellite loci and samples from 13 and 6 natural populations of Oriental and European beech, respectively, we identified 5 distinct genetic clusters in Oriental beech with a divergence (FST) of 0.15 to 0.25 from European beech. Using this knowledge, we tracked the origin of 11 Oriental beech stands in Western Europe, some established in the early 1900s. In two stands of Greater Caucasus origin, we additionally genotyped offspring and found evidence for extensive hybridization, with 41.3% and 17.8% of the offspring having a hybrid status. Further, climate data revealed a higher degree of seasonality across the Oriental beech growing sites than across the planting sites in Western Europe, with some sites additionally having a warmer and drier climate. Accordingly, in one of these stands, we found evidence that bud burst of Oriental beech occurs four days earlier than in European beech. These results suggest that AGF of Oriental beech could increase the genetic diversity of European beech stands and may even help the introgression of variants that are more adapted to future climatic conditions. Our study showcases an evaluation of the benefits and risks of AGF and calls for similar studies on other native tree species.

evolutionary biology↗

bioRxiv2018

Adaptation to local climate in size, growth and phenology across 19 silver fir (Abies alba Mill.) populations from Switzerland

Attempts to identify and understand selection pressures responsible for local adaptation are central to evolutionary research. We tested whether populations of silver fir (Abies alba Mill.), sampled across a heterogeneous environment, have more strongly diverged at quantitative traits than expected from genetic drift. We genotyped 387 trees from 19 Swiss populations at 374 single-nucleotide polymorphisms (SNPs) to estimate their demographic distances, and used these to generate a null expectation for divergence in a multi-trait space including morphology and life-history traits obtained from a published common garden trial. Local soil and historical climate data were used to identify the selective environment of the source populations. Our results revealed a strong selection on height driven by temperature: trees from warm sites evolved to become taller than those from cooler sites. The evolution of growth rate, growth duration and bud break were correlated, and populations evolved towards two extreme strategies, \"start early and grow slow\" or \"start late and grow fast\", driven by precipitation seasonality. We conclude that local climate has shaped the morphology and life-history of silver fir populations since they recolonized the Alps. Our methodology provides a show-case for empirical evaluation of adaptive evolutionary strategies combining genetic data and common gardens.

evolutionary biology↗

bioRxiv2017

Genome expansion and lineage-specific genetic innovations in the world’s largest organisms (Armillaria)

Armillaria species are both devastating forest pathogens and some of the largest terrestrial organisms on Earth. They forage for hosts and achieve immense colony sizes using rhizomorphs, root-like multicellular structures of clonal dispersal. Here, we sequenced and analyzed genomes of four Armillaria species and performed RNA-Seq and quantitative proteomic analysis on seven invasive and reproductive developmental stages of A. ostoyae. Comparison with 22 related fungi revealed a significant genome expansion in Armillaria, affecting several pathogenicity-related genes, lignocellulose degrading enzymes and lineage-specific genes likely involved in rhizomorph development. Rhizomorphs express an evolutionarily young transcriptome that shares features with the transcriptomes of fruiting bodies and vegetative mycelia. Several genes show concomitant upregulation in rhizomorphs and fruiting bodies and shared cis-regulatory signatures in their promoters, providing genetic and regulatory insights into complex multicellularity in fungi. Our results suggest that the evolution of the unique dispersal and pathogenicity mechanisms of Armillaria might have drawn upon ancestral genetic toolkits for wood-decay, morphogenesis and complex multicellularity.

evolutionary biology↗