Biology subjects

Notarnicola, R. F.

Publications and source records attributed to Notarnicola, R. F..

3 recordsLinked to original sources

bioRxiv2025

A key regulator of missing-self innate immunity is polymorphic and under diversifying selection

Host-parasite co-evolution drives the diversification of host immune genes involved in the recognition of pathogen antigens and molecular patterns. In contrast, the immune genes involved in self-recognition and inhibition of immune responses against self-cells (missing-self immunity) are expected to be evolutionarily constrained. However, many pathogens, such as the Lyme disease agent Borrelia, hijack these genes to evade the immune system and may therefore select for their diversification. How these contrasting but concurrent selective forces shape the evolution of missing-self regulators is not clearly understood. To fill this gap, we investigated polymorphism and molecular signatures of selection acting on a missing-self regulator, the Complement Factor H (CFH), in bank vole populations, which are an important wild reservoir for Borrelia. We then compared the geographic structuring in the CFH domain interacting with Borrelia (CCP 20) against a genomic background represented by RAD-seq markers. We found signals of positive and diversifying selection at CCP 20, suggesting that CFH evolved in response to pressures from pathogens. Additionally, we found other innate immunity genes within the alternative complement pathway, which is regulated by CFH, under diversifying selection, highlighting its involvement in host-parasite coevolution. This study demonstrates that an innate missing-self sensor in a wild vertebrate is under diversifying selection, likely driven by pathogens.

evolutionary biology↗

bioRxiv2024

Phenotypic plasticity in response to growth temperature far outweighs other environmental and genetic causes of variation in an alpine plant

Phenotypic plasticity and rapid evolution are fundamental processes by which organisms can maintain their function and fitness in the face of environmental changes. Here we quantified the plasticity and evolutionary potential of an alpine herb Wahlenbergia ceracea. Utilising its mixed-mating system, we generated outcrossed and self-pollinated families that were grown in either cool or warm environments, and that had parents that had also been grown in either cool or warm environments. We then analysed the contribution of environmental and genetic factors to variation in a range of phenotypic traits including phenology, leaf mass per area, photosynthetic function, thermal tolerance, and reproductive fitness. The strongest effect was that of current growth temperature, indicating strong phenotypic plasticity. All traits except thermal tolerance were plastic, whereby warm-grown plants flowered earlier, grew larger, produced more reproductive stems compared to cool-grown plants. Flowering onset and biomass were heritable and under selection, with early flowering and larger plants having higher relative fitness. There was little evidence for transgenerational plasticity, maternal effects, or genotype-by-environment interactions. Inbreeding delayed flowering and reduced reproductive fitness and biomass. Overall, we found that W. ceracea has the capacity to respond rapidly to climate warming via plasticity, and the potential for evolutionary change. HighlightWe found strong plasticity to growth environment in many phenotypic traits, but little effect of parental environment, revealing capacity to respond rapidly to climate warming, and potential for evolutionary change.

ecology↗

bioRxiv2023

Transcriptional acclimation to warming temperatures of the Australian alpine herb Wahlenbergia ceracea

Understanding the molecular mechanisms of heat tolerance could help to predict the impacts of climate change on our native flora. However, much of our current understanding is derived from Arabidopsis thaliana and select crops exposed to short and intense periods of heat stress. Here, we characterise the transcriptomic response of Wahlenbergia ceracea, a perennial herb found in Australias subalpine regions, to sustained moderate warming. We contrasted responses between relatively heat-tolerant and heat-sensitive lines grown under cool (24/15 {o}C day/night) or warm (30/20 {o}C) temperatures. We observed that sustained warming up-regulated genes related to RNA regulation, including modification and splicing, and down-regulated genes associated with photosynthesis and plastid organization. Interestingly, heat-tolerant lines demonstrated a more pronounced repression of photosynthesis-associated genes, compared to heat-sensitive lines, suggesting that the regulation of the light-harvesting machinery may contribute to photosystem thermal tolerance. Co-expression analyses revealed only weak module-level correlations with direct measures of thermal tolerance. However, stronger associations were evident with chlorophyll content and photosynthetic efficiency, which might indirectly influence thermal tolerance. Prediction of transcription factors targeting warming-responsive genes implicated hormone signaling networks, especially ethylene, in contributing to differences in thermal tolerance. In conclusion, we present genomic resources for transcriptome analyses in W. ceracea and highlight the contrasting gene regulatory patterns between relatively heat-tolerant and heat-sensitive W. ceracea lines experiencing sustained moderate warming.

plant biology↗