Biology subjects

Pascual-Diaz, J. P.

Publications and source records attributed to Pascual-Diaz, J. P..

3 recordsLinked to original sources

bioRxiv2026

Cytogenomic signatures of hybridisation in the genus Carpobrotus reveal biased parental dominance

O_LIHybridisation is frequently associated with plant invasions; however, its consequences for genome organisation and chromosome evolution remain poorly understood in invasive species. We investigated the extent of hybridisation in the invasive Carpobrotus edulis--acinaciformis hybrid complex and determined the cytogenomic contribution of parental species in hybrid accessions. C_LIO_LIWe combined whole-genome sequencing, population genomic analyses, genome size estimation, repeatome characterisation, chromosome counting and fluorescence in situ hybridisation to compare parental species and hybrid accessions from South Africa and the Mediterranean Basin. C_LIO_LIPopulation genomic analyses revealed widespread hybridisation and introgression, with most invasive accessions showing admixed ancestries. Pattersons D-statistic supported asymmetric allele sharing towards C. edulis. Hybrid accessions displayed genome sizes indistinguishable from C. edulis, whereas C. acinaciformis possessed significantly larger genomes. Repeatome analyses identified marked differences in repetitive DNA composition, particularly in satellite DNA abundance and chromosomal distribution. A newly identified satellite repeat (CarpoSat) showed contrasting chromosomal patterns between parental species, whereas hybrids resembled C. edulis satellite pattern. C_LIO_LIOur results demonstrate that Carpobrotus hybrid accessions are a swarm of later-generation hybrids and backcrosses showing a strong bias towards C. edulis, indicating asymmetric introgression. These findings highlight the value of integrating cytogenetic and genomic approaches to understand genome evolution in invasive hybrid complexes. C_LI

plant biology↗

bioRxiv2025

The impact of the invasive Kalanchoe xhoughtonii on vegetated sea cliffs of the Mediterranean coasts with endemic Limonium species

Invasive alien plant species pose a serious threat to biodiversity, especially in ecologically rich regions such as the Mediterranean Basin. Among the most affected habitats are coastal communities, which host many endemic taxa and provide valuable ecosystem services. One such invasive taxa is Kalanchoe xhoughtonii, an allegedly artificial hybrid. This plant, although having demonstrated strong invasive potential, still largely remains unrecognised as a taxon of concern in Mediterranean countries, at least in national official catalogues. In this study, we assess the impact of this hybrid on coastal communities, focusing on the European Union Habitat of Community Interest (HCI) 1240--"vegetated cliffs with endemic statices (Limonium spp.)"--at two sites along the southern coast of Catalonia (NE Iberian Peninsula). Between 2022 and 2025, we conducted field surveys to document the population size, growth stages, and spatial competition with native species. Additionally, we gathered 1,422 iNaturalist occurrences of K. xhoughtonii to map its distribution across the Mediterranean Basin, assess its presence within Natura 2000 protected sites and within protected areas, including the HCI 1240, and determine its potential spread using ensemble ecological niche modelling with bioclimatic variables. Our results show that K. xhoughtonii forms dense monospecific patches in the surveyed areas that compete for space with two native Limonium species in southern Catalonia. Moreover, we confirmed 713 naturalised occurrences in the Mediterranean area, 107 were located within Natura 2000 protected sites and 58 within the HCI 1240 included in protected sites. Ecological niche modelling indicates high climatic suitability across 93% of western and 59% of eastern Mediterranean Natura 2000 sites containing the HCI 1240. The findings of this study highlight the invasive potential of K. xhoughtonii and support its inclusion in national catalogues of invasive species across Mediterranean basin countries. The study calls for systematic monitoring of the spread and ecological impact of this hybrid species in coastal community habitats.

ecology↗

bioRxiv2025

The Winner Takes It All: a single genotype of Kalanchoe xhoughtonii is a global invader

Background and AimsInvasive alien plant species pose a global challenge, and their impact is amplified by globalisation and the accelerating pace of climate change. In mild-climate regions, drought-tolerant invasive plants showing broad environmental tolerance have a competitive advantage. One example is Kalanchoe xhoughtonii (Crassulaceae), popularly known as "mother of millions". It is a hybrid resulting from the interploid cross between K. daigremontiana and K. delagoensis, both native to Madagascar. Kalanchoe xhoughtonii, propagated as an ornamental plant, has emerged as a global invader in less than a century. Four morphotypes of this hybrid have been identified, with different ploidy levels and varying invasive capacities. Here we aim to investigate the genomic variability behind the invasion success of Kalanchoe xhoughtonii. MethodsWe sampled 57 accessions of Kalanchoe xhoughtonii, K. daigremontiana, K. delagoensis and closely related taxa, including old herbarium materials, from all over the world. We analysed genome size, chromosome numbers, sequenced the whole genome, analysed the complete plastome sequence of each accession, and studied the diversity of the ribosomal RNA genes. We also performed a detailed phylogenomic study using nuclear BUSCO genes. Key ResultsOur study reveals the genetic and cytogenetic variability between morphotypes, and shows that a single tetraploid genotype (morphotype A) dominates all populations, emerging as the first reported clonal hybrid capable of worldwide colonisation. Morphotype A shows a striking genetic uniformity, high phenotypic plasticity, and extremely high rates of vegetative reproduction, representing an example of a "general-purpose genotype". ConclusionsThe astonishing reproductive capacity, broad adaptability and the speed at which K. xhoughtonii is colonising new regions by clonal spread highlight the importance of understanding hybridisation and polyploidy in the invasion of ecosystems. Our findings call for the need for risk assessments before developing new hybrids for ornamental plant breeding that may exhibit invasive characteristics.

plant biology↗