Biology subjects

Schiestl, F. P.

Publications and source records attributed to Schiestl, F. P..

7 recordsLinked to original sources

bioRxiv2026

Abiotic and biotic ecological factors affect the genomic consequences of plant-butterfly coevolution

Variation in abiotic and biotic factors drives unique coevolutionary trajectories, yet we know little about how individual and interactive effects from such environmental factors alter the genomic basis of coadaptation. As a follow-up study after 6 generations of experimental coevolution, we analyzed whole-genome re-sequencing data from fast-cycling Brassica rapa plants that coevolved with a pollinating herbivore (Pieris rapae butterflies) in two different temperature environments (ambient/elevated) and in the presence/absence of bumblebees that did not coevolve. We found that genomic divergence between plant populations coevolving in the presence or absence of bumblebees was larger relative to plant populations coevolving in different temperature environments. Next, we found that the presence of bumblebees affected the number of genomic regions under selection differently depending on which temperature environment plants coevolved in. More specifically, we found no genomic regions under selection when plants coevolved in elevated temperatures and in the absence of bumblebees, but the most genomic regions under selection when plants coevolved in elevated temperatures and in the presence of bumblebees. Finally, genomic evolution underlying defense traits was larger when plants coevolved in the presence of bumblebees relative to when plants coevolved in the absence of bumblebees, which fits the prediction of coevolution being more antagonistic in the presence of a non-herbivorous co-pollinator. Overall, our results highlight how modifications in temperature and community context, potentially stemming from global environmental change, will affect the genomic basis of coevolution.

evolutionary biology↗

bioRxiv2024

Selection for later flowering time in an orchid through frost damage and pollinator activity

Flowering time is a key trait for plant reproductive success ensuring both overlap with pollinator activity and favorable conditions for fruit development. To quantify selection on flowering time, we individually marked 1250 plants of the Small Spider Orchid, Ophrys araneola RchB., in six populations in Northern Switzerland and surveyed them during three years. We recorded the date of first flowering, frost damage, and fruiting success of individual plants. In addition, we analyzed historical records of the orchid and its only verified pollinator, the solitary bee Andrena combinata in Northern Switzerland, to estimate potential desynchronization due to climate change. We documented strong selection for later flowering driven by frost damage, with all populations showing significant selection for later flowering in at least one year. Selection for later flowering driven by pollination (fruit set) could only be analyzed in one population due to the overall low fruit set, where it was significant in one year. The historical data from between 1970 and 2019 indicated low synchronization between orchid flowering and bee occurrence, with mean flowering three weeks earlier than the mean peak of bee occurrence, corroborating selection for later flowering through fruit set. The data also showed a significant advance of flowering time and bee-occurrence in the last decades, but to a similar degree in orchids and bees, hence without an indication of increasing desynchronization through climate change. Our study shows that selection for later flowering is mostly caused by frost damage, but also by the little synchronized flowering and pollinator activity, which is however unlikely to be a consequence of climate change in this orchid.

evolutionary biology↗

bioRxiv2023

Uncovering genes involved in pollinator-driven mating system shifts and selfing syndrome evolution in Brassica rapa

BackgroundShifts in pollinator occurrence and their pollen transport effectiveness drive the evolution of mating systems in flowering plants. A decline in pollinator numbers can lead to the phenotypic evolution of floral traits favoring self-pollination (selfing syndrome). Understanding the genomic basis involved in such shifts of the mating system is crucial for predicting a species persistence or extinction under changing biotic and abiotic stressors in natural populations. We investigated loci showing high genetic differentiation before and after selection in fast-cycling Brassica rapa that were associated with rapid phenotypic evolution toward the selfing syndrome (reduction in petal width, stamen and pistil length, and herkogamy). Combining a genotyping-by-sequencing (GBS) approach with a genome-wide association study (GWAS), we shed light onto the genetic basis associated with the mating system shift over nine generations of pollination by Episyphrus balteatus (hoverflies), an abundant pollinator of B. rapa. Moreover, we functionally validated the involvement of candidate genes associated with changes in floral morphology by studying corresponding mutants in the model plant Arabidopsis thaliana. ResultsWe found that the mating system of B. rapa shifted from predominantly outcrossing to mixed mating with high rates of autonomous selfing, accompanied by a rapid reduction of floral morphological traits and herkogamy involving many loci. We found 31 candidate genes associated with the affected traits that were involved in a wide range of functions from DNA/RNA binding to transport. Our functional validation in A. thaliana confirmed that four of the identified genes are indeed involved in regulating the size of floral organs. Interestingly, two genes, both coding for the same protein complex responsible for active DNA methylation were successfully validated and closely linked to two correlated phenotypic traits, namely pistil and stamen length. ConclusionsAltogether, our study shows that hoverfly pollination leads to rapid evolutionary changes of the mating system through polygenic changes, highlighting the importance of using genomic approaches to understand pollinator-driven plant adaptation.

plant biology↗

bioRxiv2022

Genomic local adaptation of a generalist plant species to pollinator communities and abiotic factors

The reproductive success of generalist flowering plants is influenced by a complex ecological network that includes interactions with a diverse pollinator community and abiotic factors. However, knowledge about of the adaptative potential of plants to complex ecological networks and the underlying genetic mechanisms is still limited. Based on a pool-sequencing approach of 21 natural populations of Brassica incana in Southern Italy, we combined a genome-environmental association analysis with a genome scan for signature of selection to discover genetic variants associated with ecological variation. We demonstrated that B. incana is locally adapted both to the identity of functional categories and overall pollinator interactions. Interestingly, we observed only few shared candidate genes associated with long-tongue bees, soil texture, and temperature variation. Our results highlight the genomic architecture of generalist flowering plant adaptation to complex biotic interactions, and the importance of considering multiple environmental factors to describe the adaptive landscape of plant populations.

plant biology↗

bioRxiv2022

Plant phenotypic plasticity changes pollinator-mediated selection

Many organisms change their phenotype in response to the environment, a phenomenon called phenotypic plasticity. Yet we hardly understand how such plasticity can affect biotic interactions and the resulting phenotypic selection. Here we use fast cycling Brassica rapa plants in a proof-of-concept experiment in the greenhouse to study the link between plasticity and selection. We detected strong plasticity in morphology, nectar, and floral scent in response to different soil types and aphid herbivory. We found positive selection on nectar and several morphological traits. Bumblebee-mediated selection on a principle component representing plant height, flower number, and flowering time (mPC3) differed depending on soil type and herbivory. For plants growing in richer soil, selection was stronger in the absence of herbivores, whereas for plants growing in poorer soil selection was stronger with herbivory. We showed that bumblebees visited tall plants with many flowers over-proportionally when they were rare (i.e. in plants in poor soil with herbivory), thus causing stronger positive selection on this trait-combination. We suggest that with strong plasticity under most stressful conditions, a shift in pollinator behavior may speed up adaptation to local environmental factors.

evolutionary biology↗

bioRxiv2021

Rapid genomic evolution in Brassica rapa with bumblebee selection in experimental evolution

BackgroundInsect pollinators shape rapid phenotypic evolution of traits related to floral attractiveness and plant reproductive success. However, the underlying genomic changes remain largely unknown despite their importance in predicting adaptive responses to natural or to artificial selection. Based on a nine-generation experimental evolution study with fast cycling Brassica rapa plants adapting to bumblebees, we investigate the genomic evolution associated with the previously observed parallel phenotypic evolution. In this current evolve and resequencing (E&R) study, we conduct a genomic scan of the allele frequency changes along the genome in bumblebee-pollinated and hand-pollinated plants and perform a genomic principal component analysis (PCA). ResultsWe highlight rapid genomic evolution associated with the observed phenotypic evolution mediated by bumblebees. Controlling for genetic drift, we observe significant changes in allelic frequencies at multiple loci. However, this pattern differs according to the replicate of bumblebee-pollinated plants, suggesting putative non-parallel genomic evolution. Finally, our study underlines an increase in genomic differentiation implying the putative involvement of multiple loci in short-term pollinator adaptation. ConclusionsOverall, our study enhances our understanding of the complex interactions between pollinator and plants, providing a steppingstone towards unravelling the genetic basis of plant genomic adaptation to biotic factors in the environment.

evolutionary biology↗

bioRxiv2019

Floral signals evolve in a predictable way under artificial and pollinator selection in Brassica rapa using a G-matrix

BackgroundAngiosperms employ an astonishing variety of visual and olfactory floral signals that are generally thought to evolve under natural selection. Those morphological and chemical traits can form highly correlated sets of traits. It is not always clear which of these are used by pollinators as primary targets of selection and which would be indirectly selected by being linked to those primary targets. Quantitative genetics tools for predicting multiple traits response to selection have been developed since long and have advanced our understanding of evolution of genetically correlated traits in various biological systems. We use these tools to predict the evolutionary trajectories of floral traits and understand the selection pressures acting on them. ResultsWe used data from an artificial and a pollinator (bumblebee, hoverfly) selection experiment with fast cycling Brassica rapa plants to predict evolutionary changes of 12 floral volatiles and 4 morphological floral traits in response to selection. Using the observed selection gradients and the genetic variance-covariance matrix (G-matrix) of the traits, we showed that the responses of most floral traits including volatiles were predicted in the right direction in artificial- and bumblebee-selection experiment, revealing direct and indirect targets of bumblebee selection. Genetic covariance had a mix of constraining and facilitating effects on evolutionary responses. We further revealed how G-matrices evolved in the selection processes. ConclusionsOverall, our integrative study shows that floral signals, and especially volatiles, evolve under selection in a mostly predictable way, at least during short term evolution. Evolutionary constraints stemming from genetic covariance affected traits evolutionary trajectories and thus it is important to include genetic covariance for predicting the evolutionary changes of a comprehensive suite of traits. Other processes such as resource limitation and selfing also needs to be considered for a better understanding of floral trait evolution.

evolutionary biology↗