Biology subjects

Orsucci, M.

Publications and source records attributed to Orsucci, M..

9 recordsLinked to original sources

bioRxiv2026

Living in a metal-rich world: Enhanced growth and reduced metal accumulation in Fusarium fungi from the Kiirunavaara iron ore mine

BackgroundHuman activities such as mining generally lead to increased heavy metal concentrations in the environment. While traditional remediation techniques are often costly, the use of fungi as bioremediators, known as mycoremediation, is increasingly gaining attention as a sustainable approach for removal of heavy metals. Here, we evaluated heavy metal levels inside the Kiirunavaara iron ore mine in Northern Sweden and analysed fungal responses to various metal concentrations by comparing growth and metal uptake in mine-derived isolates and closely related control isolates. ResultsSediments inside the mine were enriched in heavy metals compared to those from the outlet of the mine to natural lakes. Six Fusarium isolates were recovered from contaminated mining environments: five isolates from inside the mine were identified as Fusarium oxysporum, and one isolate from the outlet was identified as Fusarium tricinctum. Isolates from the mine and outlet showed overall higher survival and biomass production in presence of copper, iron, and zinc across a range of concentrations (up to 1000 mg/L) compared to control isolates. At the same time, these isolates often exhibited reduced relative metal uptake. As a result, mycoremediation potential, assessed as total uptake in the grown mycelium, was isolate-dependent. ConclusionsBased on these results, we conclude that Fusarium isolates from the Kiirunavaara mine show increased growth in media enriched with heavy metals compared to closely related control isolates. We additionally show that mycoremediation potential is not necessarily associated with environmental origin. Instead, mycoremediation potential should be evaluated on a case-by-case basis for each isolate and based on specific needs for mycoremediation.

microbiology↗

bioRxiv2022

Convergence and molecular evolution of floral fragrance after independent transitions to self fertilization

The study of the independent evolution of similar characters can highlight important ecological and genetic factors that drive phenotypic evolution. The transition from reproduction by outcrossing to self-fertilization has occurred frequently throughout plant evolution. A common trend in this transition is the reduction of flower features in the selfing lineages, including display size, flower signals and pollinators rewards. These changes are believed to evolve because resources invested in building attractive flowers are reallocated to other fitness functions as the pressures to attract pollinators decrease. We investigated the similarities in the evolution of flower fragrance after independent transitions to self-fertilization in Capsella. We identified a large number of compounds that are similarly changed in different selfer lineages, such that the composition of the flower scent can predict the mating system in this genus. We further demonstrate that the emission of some of these compounds convergently evolved based on mutations in different genes. In one of the Capsella selfing lineages, the loss of {beta}-ocimene emission was caused by a mutation altering subcellular localization of the ortholog of TERPENE SYNTHASE 2 without apparent effects on its biosynthetic activity. This mutation appears to have been selected at the early stage of this selfing lineage establishment through the capture of a variant segregating in the ancestral outcrossing population. The large extent of convergence in the independent evolution of flower scent, together with the evolutionary history and molecular consequences of a causal mutation, suggest that the emission of specific volatiles has important fitness consequences in self-fertilizing plants without obvious energetic benefits.

plant biology↗

bioRxiv2020

Phenotypic plasticity, population structure and adaptation in a young weed species with a worldwide distribution

The colonization success of a species depends on phenotypic plasticity, adaptive potential and population structure. Assessing their relative contributions during a colonization process is challenging, and a large-scale experiment had yet to be done. In this study, we attempted to tease apart their effects on the fitness of one of the most common plant on Earth, the shepherds purse (Capsella bursa-pastoris), a self-fertilizing and allopolyploid weed, with a worldwide distribution. The overarching goal is to eventually understand how the shepherds purse extensive distribution range was established so rapidly. To do so, we carried out three common gardens, located in Europe, Asia and North America, and measured several life-history traits on field-collected accessions belonging to three distinct genetic clusters (Middle East, Europe, and Asia). Our experiment showed that (i) the success of C. bursa-pastoris is mainly due to its high degree of phenotypic plasticity; and (ii), genetic cluster effect reflected a classic pattern observed in core vs marginal populations, with the Middle Eastern cluster (putative core population) outperforming the European and Asian clusters. This study therefore revealed, in a model species, different relative contributions of plasticity and adaptation to fitness, depending on the population and the time since colonization occurred.

evolutionary biology↗

bioRxiv2020

The selfing syndrome overshadows other differences when comparing fitness across Capsella species

Self-fertilization has recurrently evolved from outcrossing. Self-fertilization provides an advantage in the short-term as individuals do not require a mate to reproduce, but self-fertilization is also associated with both decreased genetic diversity and accumulation of weakly deleterious mutations, which could, however, be alleviated in polyploid selfers. If pollinators are not limited, individual fitness is thus expected to be higher in outcrossers than in selfers. We measured several life history traits in four Capsella species under two different treatments (disturbed and undisturbed) to assess the effects of mating system and ploidy level on reproductive, vegetative and phenological traits. The experiment was carried out outdoor in Northwest Greece, within the range of the obligate outcrossing species, C. grandiflora, so it could be naturally pollinated and its fitness directly compared to that of its self-fertilizing relatives. Disturbance of the environment did not affect the phenotype in any of the four species. However, for most traits the obligate outcrossing species performed better than all selfing ones. In contrast, polyploidy did not seem to confer an advantage in terms of survival or reproduction compared to diploidy. Finally, plants from Asia and northern Europe had lower performances than accessions from southern Europe and the Middle-East.

evolutionary biology↗

bioRxiv2019

Ecological strategy and genetic load in the shepherd's purse (Capsella bursa-pastoris) from the core and the limit of its natural range.

Species range expansion is a complex process whose outcome depends on the interplay of demographic, environmental and genetic factors. In plants, self-fertilizing species that do not require a mate to reproduce usually show higher invasive ability. However, this comes at a cost as both selfing and bottlenecks occurring during colonization lead to an increase in deleterious mutations accumulation (genetic load). Although they are theoretically clearly spelled out, the relationships between genomic and phenotypic characteristics of expanding populations have hitherto rarely been characterized. In the present study we analyzed how different accessions of the shepherds purse, C. bursa-pastoris, coming from the front of colonization or from the core of the natural range performed under increasing density of competitors. We first showed that, as expected, accessions from the front of colonization performed the worst for most life history traits compared with accessions from core populations. Second, competitor density had a negative impact on both vegetative growth and reproductive output in term of fruits production for all accessions. However, somewhat unexpectedly given their higher genetic load and their lower absolute performance, accessions from the front of colonization were less affected by competition than accessions from the core of the species range. This could be due to phenotypic tradeoffs and a shift in phenology that allow the accessions from the front of colonization to avoid competition. These results are discussed in terms of ecological strategies of expanding populations.

evolutionary biology↗

bioRxiv2018

Assessing the potential for assisted gene flow using past introduction of Norway spruce in Southern Sweden: Local adaptation and genetic basis of quantitative traits in trees.

Norway spruce (Picea abies) is a dominant conifer species of major economic importance in Northern Europe. Extensive breeding programs were established to improve phenotypic traits of interest. In southern Sweden seeds used to create progeny tests were collected on about 3000 trees of outstanding phenotype (\"plus\" trees) across the region. Some were of local origin but many were recent introductions from the rest of the natural range. The mixed origin of the trees together with partial sequencing of the exome of >1,500 of these trees and phenotypic data retrieved from the Swedish breeding program offered us a unique opportunity to dissect the genetic basis of local adaptation of three quantitative traits (height, diameter and budburst). Through a combination of multivariate analyses and genome-wide association studies, we showed that there was a very strong effect of geographical origin on growth (height and diameter) and phenology (budburst) with trees from southern origins outperforming local provenances. Association studies also indicated that growth traits were highly polygenic and budburst somewhat less. Hence, our results suggest that assisted gene flow and genomic selection approaches could help alleviating the effect of climate change on P. abies breeding programs in Sweden.

evolutionary biology↗

bioRxiv2018

Towards the new normal: Transcriptomic and genomic changes in the two subgenomes of a 100,000 years old allopolyploid, Capsella bursa-pastoris

Allopolyploidy has played a major role in plant evolution but its impact on genome diversity and expression patterns remains to be understood. Some studies found important genomic and transcriptomic changes in allopolyploids, whereas others detected a strong parental legacy and more subtle changes. The allotetraploid C. bursa-pastoris originated around 100,000 years ago and one could expect the genetic polymorphism of the two subgenomes to become more similar and their transcriptomes to start functioning together. To test this hypothesis, we sequenced the genomes and the transcriptomes (three tissues) of allote-traploid C. bursa-pastoris and its parental species, the outcrossing C. grandiflora and the self-fertilizing C. orientalis. Comparison of the divergence in expression between subgenomes, on the one hand, and divergence in expression between the parental species, on the other hand, indicated a strong parental legacy with a majority of genes exhibiting a conserved pattern and cis-regulation. However, a large proportion of the genes that were differentially expressed between the two subgenomes, were also under trans-regulation reflecting the establishment of a new regulatory pattern. Parental dominance varied among tissues: expression in flowers was closer to that of C. orientalis and expression in root and leaf to that of C. grandiflora. Since deleterious mutations accumulated preferentially on the C. orientalis subgenome, the bias in expression towards C. orientalis observed in flowers suggests that expression changes could be adaptive and related to the selfing syndrome, while biases in the roots and leaves towards the C. grandiflora subgenome may be reflective of the differential genetic load.

evolutionary biology↗

bioRxiv2018

Transcriptional plasticity evolution in two strains of Spodoptera frugiperda (Lepidoptera: Noctuidae) feeding on alternative host-plants

AO_SCPLOWBSTRACTC_SCPLOWSpodoptera frugiperda, the fall armyworm (FAW), is an important agricultural pest in the Americas and an emerging pest in sub-Saharan Africa, India, East-Asia and Australia, causing damage to major crops such as corn, sorghum and soybean. While FAW larvae are considered polyphagous, differences in diet preference have been described between two genetic variants: the corn strain (sf-C) and the rice strain (sf-R). These two strains are sometimes considered as distinct species, raising the hypothesis that ost plant specialization might have driven their divergence. To test this hypothesis, we irst performed controlled reciprocal transplant (RT) experiments to address the impact of plant diet on several traits linked to the fitness of the sf-C and sf-R strains. The phenotypical data suggest that sf-C is specialized to corn. We then used RNA-Se to identify constitutive transcriptional differences between strains, regardless of diet, in laboratory as well as in natural populations. We found that variations in mitochon rial transcription levels are among the most substantial and consistent differences between the two strains. Since mitochondrial genotypes also vary between the strains, we believe the mitochondria may have a significant role in driving strain divergence.

evolutionary biology↗

bioRxiv2018

Transcriptomic response to host and non-host plants during oviposition in two closely related moth species

We present here a comprehensive analysis of the transcriptomic response to plant environments in ovipositing females of two sibling species of phytophagous moths affiliated to different host ranges: the European corn borer (ECB) and the adzuki bean borer (ABB). We first assembled and annotated a de novo reference transcriptome based on a high throughput RNA sequencing of females placed in different plant environments, then we measured differences in gene expression between ECB and ABB, and also within each moth species between environments. We further related the differentially expressed (DE) genes to the host preference in ECB and ABB and highlighted the functional categories involved. More specifically, we conducted an analysis on chemosensory genes previously characterized in ECB, ABB and other related Ostrinia species, as these genes are considered as good candidates for the host recognition before oviposition.\n\nOverall, we recorded more DE genes in ECB than in ABB samples, what could highlight the higher strength of the host specialization in ECB compared to ABB as observed at the behavioral level. We also noticed that the genes involved in the preference for their respective host were different between ECB and ABB. At the functional level, the response to plant environment in ECB and ABB during oviposition involved many processes, including the chemosensory repertoire as expected, but also metabolism of carbohydrates, lipids, proteins, and amino acids, detoxification mechanisms and immunity.\n\nAll together, our results allowed identifying genes and functions candidates for specialization and also for the species divergence between ECB and ABB. By ad-hoc categorization, we discriminated some genes responding to the environment with similar or divergent pattern in ECB and ABB. Among them, we highlighted new lines of research like carbohydrates metabolism or virus and retrovirus dynamics.

evolutionary biology↗