Biology subjects

Varone, L.

Publications and source records attributed to Varone, L..

4 recordsLinked to original sources

bioRxiv2026

Contemporary ecological heterogeneity shapes candidate adaptive genomic variation across the native range of an invasive herbivore

Ecological heterogeneity within a species native range can shape genomic variation available for subsequent range expansion and biological invasion. The cactus moth, Cactoblastis cactorum, is a South American oligophagous herbivore on Opuntia that has become an invasive pest outside its native range. In Argentina, populations span wide climatic and geographic gradients and exploit both native Opuntia species and the introduced crop O. ficus-indica. Using ddRADseq data from 136 individuals across 28 populations, we combined genome-wide differentiation scans (XtX), a host-use contrast, and genotype-environment association (GEA) analyses to identify candidate genomic signatures associated with contemporary ecological variation. XtX analyses detected 12 candidate regions, whereas the host-use contrast identified 17 regions differentiating populations sampled from O. ficus-indica and native Opuntia, several of which persisted in a geographically restricted sensitivity analysis. GEA analyses identified 167 covariate-specific loci, including candidate genes associated with detoxification and metabolism (CYP6B2), oxygen-sensing pathways (Egln1), and circadian regulation (TIMELESS). Convergence among analyses was limited but stronger than expected by chance. Temperature-associated loci in fax and Bag6 occurred within an XtX candidate region, whereas Hspg2 was independently recovered in host-use and environmental analyses and retained after geographic restriction. Most candidate variants occurred in non-coding genomic contexts, protein-altering variants were uncommon, and candidate genes spanned diverse functions, consistent with a potentially regulatory and polygenic architecture of adaptation. Overall, our results reveal a heterogeneous genomic landscape associated with climatic variation and introduced-host use, with recurrent loci providing the strongest evidence for localized adaptive differentiation across the native range of C. cactorum.

evolutionary biology↗

bioRxiv2022

Climatic variations along an aridity gradient drive significant trait intraspecific variability in Mediterranean species

Summer drought represents one of the main stress sources stress for plant communities in the Mediterranean region. Plants can adopt several response strategies to cope with stress, reflected in the adoption of specific Plant Functional Traits (PFTs). Trait-based approaches commonly meet three critical issues: they overlook Intraspecific Variability (ITV), they focus on a large spatial scale, or they focus on single trait responses to stress. In this study, we present evidence for a significant amount of ITV in morphological and anatomical trait syndromes observed between three local populations of Phyllirea latifolia, Pistacia lentiscus and Quercus ilex, distributed along an aridity gradient. Thicker, more physiologically expensive leaves and lower heights found in the drier sites mainly conform to drought-resistance strategies. Interestingly, PFTs from Cistus salviifolius were found not to vary between sites. This implies that not all species vary at the same geographical scale, possibly depending on their different successional role. The main implication behind our findings is that climate can easily drive significant ITV in multiple traits among plant populations, even at a local scale, although trait responsiveness might be species-specific. Different plant populations hailing from the same geographical regions might thus respond differently to climate change. HIGHLIGHTVariations in Plant Functional Traits from several Mediterranean species found along an aridity gradient on a local (<60Km radius) scale; responses consistent to reported drought adaptations.

ecology↗

bioRxiv2021

An updated framework to account for inter-individual variability when quantifying phenotypic variation

O_LIIn trait-based ecology, phenotypic variation (PVar) is often quantified with measures that express average differences between populations standardized in the range 0-1. A major problem with these measures is that they disregard the within-population trait variability. In addition, most of these measures cannot be decomposed across scales. This can alter their interpretation, thus limiting their applicability. C_LIO_LITo overcome these problems, we propose a new measure, the Phenotypic Dissimilarity Index (PhD) that is insensitive to the within-population interindividual trait variability. Likewise, PhD can be used to quantify PVar between individuals in a population while accounting for the PVar within individuals. C_LIO_LIUsing simulated and real data, we showed that PhD index correctly quantifies PVar when the within-population trait variability is not negligible, as in many ecological studies. By accounting for within-population trait variability, the PhD index generally provides a more parsimonious quantification of PVar across an environmental gradient compared to other estimators. C_LIO_LITraits sampled within a species have an inherent variability. Accounting for such variability is essential to understand species phenotypic responses to environmental cues. As such, the PhD index will provide ecologists with an asset to reliably quantify and compare PVar within and between species across environmental gradients at different scales. We also provide an R function to calculate the PhD index. C_LI

ecology↗

bioRxiv2017

Leaf Rolling As Indicator Of Water Stress In Cistus incanus From Different Provenances

The relationship between leaf rolling and physiological traits under imposed water stress conditions was analyzed in C. incanus representative saplings collected at different altitudes (i.e. Castelporziano, 41{degrees}45'N, 12{degrees}26'E, 0 m a.s.l. and Natural Park of Monti Lucretili, 42{degrees}33'N, 12{degrees}54'E, 750 m a.s.l) and grown ex-situ. The hypothesis that leaf rolling reflected physiological changes occurring during water stress irrespective to the different acclimation to cope with water stress was tested.\n\nOn the whole, the results show that leaf rolling is associated to an increased sub-stomatal CO2 concentration (Ci) and a decreased carboxylation efficiency (Ce). Moreover, leaf rolling in C. incanus leaves might be involved in protecting the PSII complex under water stress during the progressive inhibition of photosynthetic metabolism.

plant biology↗