Biology subjects

Szukala, A.

Publications and source records attributed to Szukala, A..

3 recordsLinked to original sources

bioRxiv2024

Limitations of ad hoc genotyping in detecting ash dieback tolerance in Fraxinus excelsior

Ash dieback (ADB), caused by the invasive alien fungal pathogen Hymenoscyphus fraxineus, is an emerging disease that poses major threats to the survival of common ash (Fraxinus excelsior) in Europe. Here, we report on a field trial aiming at the identification of ADB tolerant genotypes while encompassing the genetic diversity of common ash in Austria. Over 35,000 progenies from more than 600 putative tolerant mother trees were assessed for ADB symptoms over a period of three years. One tolerant and one susceptible progeny from a subset of the mother tree range (570 trees) were genotyped using the 4TREE array, a genotyping tool developed specifically to screen common ash provenances for their tolerance to ash dieback. We aimed to (1) better characterize the genetic structure of common ash in Austria, (2) identify hybrids between common ash and F. angustifolia (narrow-leaved ash), (3) detect genetic loci associated with tolerance to ADB, and (4) identify genetic variation associated with abiotic factors such as temperature and precipitation influencing the severity of ADB. We identify ash individuals from Eastern Austria matching putative hybrids with F. angustifolia showing varying degrees of F. angustifolia ancestry in structure analyses. The non-hybrid gene pool is characterized by shallow genetic structure following a west to east geographic pattern. In contrast to our expectations, genotype-damage association analyses overall fail to detect SNPs associated with tolerance to ADB. Our findings underscore that the polygenic architecture governing tolerance and the rapid decay of genomic linkage disequilibrium (LD) (within approximately 10 kb) significantly limit the ability to identify association outliers using the 4TREE SNP array. This highlights the constrained utility of chip genotyping approaches for this specific purpose. In contrast, the array proves successful in detecting hybrids between common ash and narrow-leaved ash, as well as outlier SNPs associated with abiotic predictors (such as annual precipitation and temperature) known to influence the severity of ADB damage.

genetics↗

bioRxiv2022

Parallel adaptation to lower altitudes is associated with enhanced plasticity in Heliosperma pusillum (Caryophyllaceae)

High levels of phenotypic plasticity are thought to be inherently costly in stable or extreme environments, but enhanced plasticity may evolve as a response to novel environments and foster adaptation. Heliosperma pusillum forms pubescent montane and glabrous alpine ecotypes that diverged recurrently and polytopically (parallel evolution). The specific montane and alpine localities are characterized by distinct temperature conditions, available moisture and light. To disentangle the relative contribution of constitutive versus plastic gene expression to altitudinal divergence, we analyze the transcriptomic profiles of two parallely evolved ecotype pairs, grown in reciprocal transplantations at native altitudinal sites. In both ecotype pairs, only a minor proportion of genes appear constitutively differentially expressed between the ecotypes regardless of the growing environment. Both derived, montane populations bear comparatively higher plasticity of gene expression than the alpine populations that can be considered in this system as ancestor-proxies. Genes that change expression plastically and constitutively underlie similar ecologically relevant pathways, related to response to drought and trichome formation. Other relevant processes, such as photosynthesis, seem to rely mainly on plastic changes. The enhanced plasticity consistently observed in the montane ecotype likely evolved as a response to the newly colonized niche. Our findings confirm that directional changes in gene expression plasticity can shape initial stages of phenotypic evolution, likely fostering adaptation to novel environments. Significance StatementUnderstanding the importance of phenotypic plasticity for fast adaptation to stress is very timely for breeding and current environmental challenges. Our study of an alpine plant in the carnation family evidences an increased level of expression plasticity in early stages of adaptation to hotter and drier habitats.

evolutionary biology↗

bioRxiv2021

Polygenic routes lead to parallel altitudinal adaptation in Heliosperma pusillum (Caryophyllaceae)

Understanding how organisms adapt to the environment is a major goal of modern biology. Parallel evolution - the independent evolution of similar phenotypes in different populations - provides a powerful framework to investigate the evolutionary potential of populations, the constraints of evolution, its repeatability and therefore its predictability. Here, we quantified the degree of gene expression and functional parallelism across replicated ecotype formation in Heliosperma pusillum (Caryophyllaceae), and gained insights into the architecture of adaptive traits. Population structure analyses and demographic modelling support a previously formulated hypothesis of parallel polytopic divergence of montane and alpine ecotypes. We detect a large proportion of differentially expressed genes (DEGs) underlying divergence within each replicate ecotype pair, with a strikingly low amount of shared DEGs across pairs. Functional enrichment of DEGs reveals that the traits affected by significant expression divergence are largely consistent across ecotype pairs, in strong contrast to the non-shared genetic basis. The remarkable redundancy of differential gene expression indicates a polygenic architecture for the diverged adaptive traits. We conclude that polygenic traits appear key to opening multiple routes for adaptation, widening the adaptive potential of organisms.

evolutionary biology↗