Candidate genes and traits
A1: Adaptive potential of the leaf economics spectrum in the Brassicaceae
Photosynthesis is the primary source of chemical energy for plants and, as such, crucial for plant fitness and ecology. Variation in leaf structure and anatomy influences the photosynthetic efficiency and carbon assimilation under different environmental conditions. This project will link intra- and inter-specific genetic variation in leaf traits with variation in photosynthetic efficiency under stress in all Brassicaceae species studied in the CRC. This project aims to unravel the contribution of leaf-trait-variation and photosynthetic performance to the genetic basis of ecological specialization in the Brassicaceae.
A2: Fitness effects of molecular variants affecting leaf area and economics spectrum of Hordeum vulgare
The leaf is the most important photosynthetic organ and has a major impact on energy assimilation, growth and fitness of plants. In this project, we propose to characterize natural variation in leaf shape and photosynthesis (leaf economics spectrum) of barley under diverse environmental conditions, clarify its association with plant performance and fitness, and isolate genetic variants controlling these traits. We will thus reveal genetic and environmental factors controlling leaf-level resource economics in a species and how this is linked to whole-plant physiology, plant performance, and ultimately, fitness.
A3: Adaptive potential of temperature mediated plasticity in Cardamine hirsuta
Leaves are of considerable ecophysiological significance because they fix carbon via photosynthesis but also release water through evapotranspiration. Consequently, leaf shape can influence both plant growth and abiotic stress responses. Although differences in leaf form show high heritability, the environment, too, can influence leaf form, resulting in phenotypic plasticity in this trait. We will study the genetic basis for this plasticity and its physiological consequences in the small ruderal plant species Cardamine hirsuta, an emerging model for comparative ecological genetics.
A4: Genetic basis and ecological importance of adaptive myxospermic strategies to drought stress in the Camelineae tribe and the Brassicaceae family
The ability of seeds to survive and germinate under varying environmental conditions is crucial for the survival of plant populations. This project will evaluate the ecological role of seed mucilage composition, and link the trait to seed quality and germination in Camelina sativa, a species adapted to semiarid environments and frequently described as a competing weed. We will compare the role of mucilage synthesis and regulation genes in seed germination ability under adverse conditions in C. sativa and ruderal A. thaliana with the aim to identify and compare adaptive gene effects across these related species with different ecologies.
A5: Genetic basis of ecological variation in meiotic recombination rates
Recombination of standing variation in adapting populations is an important factor for the emergence of genotypes with improved fitness. Recently, we have developed an efficient method that enables us to characterize genetic variation in recombination rates using parallel single-cell sequencing of thousands of pollen genomes within a single sequencing experiment. We will apply this method to study variation in genome-wide meiotic recombination rates and unravel the genetic diversity of recombination in plant genomes in benign and challenging environments.
A6: Ecological importance of multi-trait regulation by a gene regulatory network
Evolutionary adaptation to environmental change often involves complex coordinated biological responses, such as the co-regulation of genes underpinning stress adaptation of multiple traits. This project assesses the ecological importance of the MBW (MYB, bHLH, WD40) pathway, a genetic network coregulating five traits that are relevant for abiotic stress resistance at different stages of a plant's life cycle. We aim to understand how genes in the network integrate responses to different environmental stresses and thus modulate phenotypic adaptation to fluctuating environments during the life time of the plant.
A7: Adaptive potential of light-signalling genes in Arabidopsis thaliana
Competition for resources is a prevalent force in structuring plant communities and natural selection, yet the mechanisms that underlie resource competition are not well understood. This project will unravel the role of light-signalling for plant competitive ability and thus the ability to survive and reproduce in dense plant stands. Experiments on light-signalling mutants and natural variants with divergent competitive ability will determine the diversity of ecological strategies associated with the ability to compete for light.
A8: Adaptive potential of iron (Fe) management in Arabidopsis thaliana in alkaline calcareous soils
Over 30% of soils available for plant growth are alkaline calcareous soils with high pH restricting the availability of iron (Fe), a crucial nutrient in plants. This project will use a large panel of A. thaliana genotypes and mutants to identify genetic variants impacting and improving plant growth in calcareous soil with a focus on the role of iron acquisition and allocation. The project will further explore how the identified genetic variants for Fe management affect tolerance to other nutrient limitations and plant-plant competition. Ultimately, we will elucidate how the plants dynamically adjust Fe homeostasis throughout the life cycle under varying nutrient availabilities and environmental challenges.
A9: Evolutionary adaptation to local soil pH in Arabidopsis halleri
Calcareous soils are characterized by high, alkaline pH levels and low availabilities of iron, a crucial nutrient in plants. Natural populations of the long-lived and stress-tolerant Arabidopsis halleri are well known for their ability to accumulate and tolerate high concentrations of heavy metals that can interfere with iron nutrition, but these populations also inhabit exceptionally diverse soils spanning a wide range of pH values. Our central objective is to decipher the molecular physiological basis of how different populations of the species A. halleri can inhabit soils with contrasting pH and thus varying availability of iron and other minerals.
A10: Adaptive potential of sulfate content in Arabidopsis thaliana and Hordeum vulgare
Resource availability is one of the main factors affecting the ecological dynamics of populations or species. The capacity of plants to preempt resources thus determines the ability of plants to face resource limitations and competition. Sulfate is an essential plant nutrient, but sulfate concentrations in soil strongly fluctuate over the life cycle of plants. This project will examine how ecologically diverse Arabidopsis thaliana and Hordeum species can adjust sulfate uptake and accumulation to fluctuating sulfate concentrations and thus sustain plant performance.
A11: Ecological importance and genetic basis of plant-microbe associations in Brassicaceae and Hordeum species exposed to environmental challenges
Beneficial microbes can increase plant growth in nutrient poor environments and improve their resistance to pathogens. However, plants may also vary in their capacity to benefit from their growth-promoting effects. We will investigate how plant genetic variation impacts on the root associated microbial community, the microbe-mediated growth promotion and stress resistance in ecologically diverse Brassicaceae and Hordeum species grown under nutrient and water limitations. This work will advance our understanding of how beneficial microbes support environmental adaptation in plants and to what extent this is mediated by host genes conserved across species.
A12: Comparative analysis of gene-specific adaptive potentials across changing environments in A. thaliana
Ute Hoecker and Juliette de Meaux
The range of a species is delimited by a set of environmental factors that together define its niche. Here, we ask how individual genes and pathways contribute to defining a species niche. We will quantify the performance of all Arabidopsis mutants studied in the consortium along nutrient, water and competition gradients to compare the relative fitness effects of the candidate genes/pathways along environmental gradients. This project will provide a protocol to annotate genes according to the environments in which they promote plant fitness and compare how the various genetic pathways and traits studied in the consortium shape the breadth of a species’ niche.
A13: Adaptive potential of protein and amino acid metabolism in Arabidopsis thaliana
Proteins and amino acids perform diverse functions in plant cells ranging from structure and metabolism to energy transformation and signaling. They also require a major investment of resources. This project will investigate how genetic control of protein and amino acid metabolic plasticity affects plant performance under changing environmental conditions. The long-term goal is to understand, which parameters of plant protein metabolism contribute to an optimized balance between growth and stress resilience during adaptation to diverse environments and to link genes to these traits.
A14: Adaptive potential of dynamic photosynthesis in Arabidopsis thaliana
The proposed work for TRR 341 seeks to determine the genetic basis of rapid photosynthetic responses in Arabidopsis thaliana and their contribution to fitness. Plants will be grown under light simulations of presence or absence of grass competitors. These will be based on diurnal measurements of light intensity and quality in current common garden experiments. Dynamic photosynthetic and fitness-related traits will be determined in an diversity panel.