Biology subjects

Balao, F.

Publications and source records attributed to Balao, F..

8 recordsLinked to original sources

bioRxiv2026

Eco-physiological and transcriptomic plasticity of Dianthus inoxianus in response to drought

Phenotypic plasticity is a key mechanism by which plants adjust their traits to environmental changes. These phenotypic adjustments are driven by plastic changes in gene expression regulated by gene regulatory networks. Drought, a major selective force in Mediterranean ecosystems, provides a powerful context to examine how genomic plasticity translates into phenotypic responses. Here, we used Dianthus inoxianus, a drought-tolerant Mediterranean carnation, in order to characterize the phenotypic and transcriptomic plasticity in response to drought stress combining ecophysiological measurements with RNA-seq, gene co-expression and gene regulatory network analyses. Most of the phenotypic traits exhibited low plasticity in response to drought, except water and osmotic potential. At transcriptome level, we identified 57 plastic genes, suggesting that drought tolerance in D. inoxianus relies predominantly on constitutive gene expression. These plastic genes were enriched in processes typically related to drought response, such as cell wall components and abscisic acid (ABA) signaling. Some plastic genes belonged to drought-responsive modules, while others were hubs in different modules acting as inter-modular connectors. Furthermore, the regulatory network revealed that these plastic genes were strongly regulated by multiple stress-responsive transcription factors, and that drought-associated modules were regulated through both ABA-dependent and ABA-independent pathways. In addition, we identified contrasting patterns of canalization and decanalization, with immune and post-transcriptional regulation remaining canalized under drought, whereas photosynthesis and amino acid metabolism became decanalized, potentially releasing cryptic genetic variation. Overall, our results emphasise that drought tolerance in D. inoxianus emerges from a strategy combining preadaptation with targeted plasticity in key molecular pathways.

genomics↗

bioRxiv2024

Small RNAs regulation and genomic harmony: insights into allopolyploid evolution in marsh orchids (Dactylorhiza)

O_LIHybridization and polyploidy are major drivers of plant diversification, often accompanied by shifts in gene expression and genome composition. Small RNAs (smRNAs) are thought to influence such genomic changes, particularly through their interactions with transposable elements (TEs). C_LIO_LIWe comparatively quantified smRNAs in established sibling allopolyploids Dactylorhiza majalis and D. traunsteineri and their diploid progenitors to assess how independent allopolyploidization events shaped smRNA landscapes. C_LIO_LIDespite independent origins, the allotetraploids exhibited substantial overlap in smRNA composition, including transgressive accumulation of smRNA near genes related to transcriptional regulation, cell division and stress response. Consistently, TE-associated 24 nt smRNAs more closely resembled the paternal and larger genome, while shorter smRNAs typically reflected the maternal and smaller genome. Nevertheless, distinct patterns were also evident: the older D. majalis showed greater accumulation of smRNAs near genes involved in transcriptional and translational regulation, while the younger D. traunsteineri displayed stronger non-additive patterns, suggesting ongoing resolution of post-polyploid meiotic and mitotic instability. C_LIO_LIOur results reveal both convergence and divergence in smRNA landscapes among independently formed allopolyploids. Our study highlights the central role of smRNAs in resolving genomic conflict, with possible implications for functional divergence and ecological innovation during polyploid evolution. C_LI Plain-language summaryWe studied two sibling marsh orchid species that arose through hybridization and genome doubling. By comparing their small RNA molecules and how these associate with genes, we found both shared and species-specific patterns. These differences reflect how the orchids genomes have changed since formation, and may explain how repeated polyploidy events contribute to genetic and ecological diversity in plants.

evolutionary biology↗

bioRxiv2024

Postglacial Genetic Legacies, Demography, and Climate Change: Setting Conservation Priorities for Silver Fir

AimClimate change challenges the adaptive capacity of several tree species. This study explores the genetic diversity and past range dynamics of silver fir (Abies alba) with the objective of set hotspots of population diversity and priorities for conservation based on climate change-induced dieback. LocationMediterranean, Europe MethodsWe perform genome-wide analysis by RAD-seq to range-wide 26 A. alba populations. ResultsWe identified two lineages in the southern range, formed by populations from the Apennine chain, from the west side, and those from the Balkans and Carpathians, from the east side. Northern range populations showed two lineages, with definite genetic differences between the westernmost populations from those from the eastern. Populations from the Northern Balkans and the NE Apennine were situated in the intermediate positions. Regarding demographics, southern populations remained stable as glacial refuges, while northern populations experienced a population decline during the middle Pleistocene due to glaciations. Although the demographic events that shaped the current spatial structure of genetic diversity of silver fir go back to the Pleistocene, human pressure during the Holocene likely led to an abrupt range decline, while recent drought events have caused widespread dieback. Main ConclusionsWe provide a generic framework for setting silver fir conservation priorities based on the phylogeographical lineages and current dieback symptoms induced by climate change. Our results support that rear edge populations might be disproportionately important for the adaptive capacity of silver fir under a climate change scenario.

evolutionary biology↗

bioRxiv2024

Functional traits and soil water availability shape competitive interactions in a diploid-polyploid complex

O_LIEven within those polyploid plant species that become established initially, only a few persist in the long term. Competitive interactions between polyploids and their ancestral cytotypes in secondary contact zones can contribute to local extinctions. Environmental factors such as water availability and functional trait divergence may influence these interactions. C_LIO_LIWe conducted a greenhouse competition experiment with four cytotypes (2x, 4x, 6x, and 12x) of Dianthus broteri under two contrasting irrigation regimes. We estimated niche and fitness differences and predicted the pairwise competitive outcomes. Additionally, we explored the influence of leaf physiological functional traits (SLA, AN, gs, LDMC, Fv/Fm, and iWUE) on competitive interactions. C_LIO_LISoil water availability modified the competitive dynamics between cytotypes and predicted competitive exclusion. Under high water availability, lower ploidy levels (2x and 4x) outcompeted higher ploidy cytotypes (12x, 6x), while the latter exhibited greater competitive abilities under low water availability. These differences were explained by functional traits related to competitive effects (SLA) and competition tolerance (AN, Fv/Fm, and iWUE). C_LIO_LISynthesis: Our study emphasizes that the long-term fate of polyploids largely depends on water availability, with high polyploids having a competitive advantage in arid environments. This ultimately highlights the role of functional traits in shaping the competitive dynamics between cytotypes. C_LI

ecology↗

bioRxiv2024

Decoupled genetic and epigenetic variation at local scale in an endemic and a widespread Erodium (Geraniaceae) species

Epigenetic states offer an additional layer of variation besides genetic polymorphism that contribute to phenotypic variation and may arise either randomly or in response to environmental factors. We hypothesize that closely related species with different life-histories and habitat requirements could show distinct patterns of intraspecific epigenetic variation. We used Restriction-site Associated DNA sequencing (RADseq) and its bisulfite-converted variant (bsRADseq) to investigate in Sierra de Cazorla (SE Spain) the genetic and epigenetic population structure of two congeneric species, the endemic woody perennial Erodium cazorlanum and the widely distributed annual herb E. cicutarium. Population genomics analyses revealed no structure in either E. cazorlanum and E. cicutarium, suggesting substantial gene flow between the study populations. In contrast, we found that the mean proportion of global DNA methylation was different between populations and species, with E. cazorlanum DNA showing higher methylation average and across-individuals variation. For each species, we searched for the loci with the strongest epigenetic differentiation between populations (differentially methylated cytosines, DMCs), and summarized them across regions (differentially methylated regions, DMRs). Multivariate analysis and hierarchical clustering of single cytosines methylation percentages did not group individuals by population, pointing to high epigenetic variation within populations. DMRs were enriched in Copia transposable elements, putatively associated with stress response in plants. Our results suggest that variation at both genetic and epigenetic levels in our study area occur mainly within natural populations of E. cazorlanum and E. cicutarium, with stronger population structure in E. cicutarium, and highlight the relevance of analyzing short distance spatial patterns.

genomics↗

bioRxiv2023

Genomic-guided conservation actions to restore the most endangered conifer in the Mediterranean Basin

Species with extremely small population sizes are critically endangered due to reduced genetic diversity, increased inbreeding, and the added threat of hybridization. Genomic tools significantly advance conservation by revealing genetic insights into endangered species, notably in monitoring frameworks. Sicilian fir is the most endangered conifer in Europe with only 30 adult trees spread across an 84-hectare area. Using 20,824 SNPs from RAD-seq employing the silver fir genome assembly and a custom 120 SNP-array, we evaluated genetic diversity, mating patterns, and effective population size in adult trees, 118 natural seedlings, and 2,064 nursery seedlings from past conservation actions. We assessed introgression from neighboring non-native fir plantations and established an intra-population assisted gene flow program selecting the most genetically dissimilar individuals and investigating the outcome through simulations. Genomic analysis unveiled significant genetic diversity among adult Sicilian firs, comparable to non-endangered Mediterranean firs with larger populations. However, the genetic diversity of the forthcoming generation declined due to high self-fertilization, leading to marked inbreeding (Fis = 0.38) and an alarmingly low effective population size (Ne = 6). Nursery seedling monitoring revealed similar selfing rates but significant introgression ([~]50%) from non-native firs. Although intra-population assisted gene flow could help to mitigate genetic loss, it may not alleviate the species vulnerability to imminent environmental challenges, perpetuating the risk of an extinction vortex. Hence, investigating the impact of Sicilian fir population decline and selfing on inbreeding depression, along with exploring the potential of hybrids for genetic load alleviation and future adaptation, is crucial for effective conservation strategies. This study stands as a compelling model for guiding conservation strategies in similarly imperiled species characterized by extremely small populations.

genomics↗

bioRxiv2023

Long-term methylome changes after experimental seed demethylation and their interaction with recurrent water stress in Erodium cicutarium (Geraniaceae)

O_LIThe frequency and length of drought periods are increasing in subtropical and temperate regions worldwide. Epigenetic responses to water stress could be key for plant resilience to this largely unpredictable challenge. Experimental DNA demethylation together with application of a stress factor stands as a suitable strategy to uncover the contribution of epigenetics to plant responses to stress. C_LIO_LIWe analysed leaf cytosine methylation changes in adult plants of the Mediterranean weed, Erodium cicutarium, after seed demethylation with 5-Azacytidine and/or recurrent water stress in a greenhouse. We used bisulfite RADseq (BsRADseq) and a newly reported reference genome for E. cicutarium to characterize methylation changes in a 2x2 factorial design, controlling for plant relatedness. C_LIO_LIIn the long-term, 5-Azacytidine treatment alone caused both hypo and hyper-methylation at individual cytosines, with substantial hypomethylation in CG contexts. In control conditions, drought resulted in a decrease in methylation level in all but CHH contexts. In contrast, the genome of plants that experienced recurrent water stress and had been treated with 5-Azacytidine increased DNA methylation level by ca. 5%. C_LIO_LISeed demethylation and recurrent drought exhibited a highly significant interaction in terms of global and context-specific cytosine methylation supporting an epigenetic contribution in response to stress at molecular level. C_LI

ecology↗

bioRxiv2021

Recurrent allopolyploidization events diversify eco-physiological traits in marsh orchids

Whole-genome duplication, in particular allopolyploidy, has shaped the evolution of angiosperms and other organisms. Structural reorganization of chromosomes and repatterning of gene expression is frequently observed in early generation allopolyploids, with potential ecological consequences. The relative contributions of environmental and intrinsic drivers to these changes are unknown. We show here that in marsh orchids (Dactylorhiza, Orchidaceae), recurrently-formed allopolyploids are characterized by distinct eco-physiologies matching their respective environments, providing us with an excellent study system to address this question. Here we integrate eco-physiological and transcriptomic comparative studies to reveal a complex suite of intertwined, pronounced differences between sibling allopolyploids. We show that Dactylorhiza majalis that is distributed in Central and Southern Europe favors meadows with mesic soils. Its sibling allopolyploid D. traunsteineri occurs in fens, characterized by soils depleted by macro- and micronutrients, mainly in previously glaciated European areas. We further uncover distinct features in their nutrient transport, leaf elemental chemistry, light-harvesting, photoprotection, and stomata activity, that appear all linked to their distinct ecologies, in particular soil chemistry differences at their native sites. Recurrent polyploidization hence enriches biodiversity through eco-physiological diversification, providing the opportunity for sibling allopolyploids to evolve as distinct evolutionary units, despite pervasive interspecific gene flow. Significance StatementWhole-genome duplication resulting in polyploidy has underpinned the evolution of flowering plants and other organisms, and is important for many crops. However, the ecological implications of polyploidy remain little understood. Here, we demonstrate that two sibling allopolyploid marsh orchid species prefer distinct habitats, and have evolved a suite of distinctive ecophysiological characters (e.g. nutrient transport, energy harvesting and photoprotection). We argue that the divergence of these characters in the nascent polyploids drove adaptation into distinct ecological niches (low nutrient fens versus meadows with mesic soils), generating ecological barriers that maintains distinct, independent lineages, even in the presence of interspecific gene flow.

evolutionary biology↗