Annals of botany最新文献

{"title":"Antibiotic resistance genes detected in lichens: insights from Cladonia stellaris.","authors":"Marta Alonso-García, Paul B L George, Samantha Leclerc, Marc Veillette, Caroline Duchaine, Juan Carlos Villarreal A","doi":"10.1093/aob/mcaf231","DOIUrl":"https://doi.org/10.1093/aob/mcaf231","url":null,"abstract":"<p><strong>Background and aims: </strong>Antibiotics are natural compounds produced by microorganisms that have long existed in ecosystems. However, the widespread clinical and agricultural use of antibiotics has intensified selective pressures on bacteria, leading to the proliferation of antibiotic resistance genes (ARGs). The increasing prevalence of these genetic elements in clinical and environmental settings now poses a major global health threat. While ARGs are well documented in anthropogenically influenced environments, their distribution and origins in remote ecosystems, such as the boreal forests, remain poorly understood. Here, we investigate the occurrence, diversity, and potential origins of ARGs in the boreal lichen Cladonia stellaris.</p><p><strong>Methods: </strong>We conducted the first targeted assessment of ARGs in lichens by analyzing 42 C. stellaris samples from northern and southern lichen woodlands (LWs) in eastern Canada. Using high-throughput quantitative PCR, we screened for 33 ARGs and three mobile genetic elements (MGEs), quantifying their relative abundance. Bacterial community composition was characterized via 16S rRNA gene sequencing. Statistical analyses evaluated geographical patterns, co-occurrence between ARGs and bacterial taxa, and the influence of latitude on ARG distribution.</p><p><strong>Key results: </strong>Ten ARGs conferring resistance to four antibiotic classes (aminoglycosides, beta-lactams, quinolones and sulfonamides), along with one MGE, were detected. The ARGs blaCTX-M-1, qnrB, and qepA were highly prevalent, with qepA often surpassing 16S rRNA gene abundance. Only qnrB showed significantly higher abundance in southern samples. Latitude significantly influenced ARG profiles, whereas bacterial community composition did not.</p><p><strong>Conclusions: </strong>Our findings demonstrate that C. stellaris harbors diverse ARGs in remote boreal ecosystems with limited anthropogenic influence. Proposed explanations for ARG presence include long-distance dispersal via bioaerosols and endogenous development within lichen microbiomes, yet these remain speculative. Future work incorporating bacterial isolation, whole-genome sequencing, metatranscriptomics, air sampling, and metabolomic profiling is necessary to unravel the ecology and evolution of ARGs in natural habitats.</p>","PeriodicalId":8023,"journal":{"name":"Annals of botany","volume":" ","pages":""},"PeriodicalIF":3.6,"publicationDate":"2025-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145111823","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"What are grana in chloroplasts of vascular plants good for?","authors":"Malgorzata Krysiak, Hui Min Olivia Oung, Helmut Kirchhoff","doi":"10.1093/aob/mcaf229","DOIUrl":"https://doi.org/10.1093/aob/mcaf229","url":null,"abstract":"<p><p>All plants and green algae contain stacked grana thylakoid membranes in their chloroplasts, underscoring an evolutionary pressure to maintain this unique structural feature. Furthermore, numerous studies demonstrate that particular lateral and vertical dimensions of grana facilitate the function, regulation, and repair of the photosynthetic machinery responsible for energy conversion. In this review, we present an updated overview of our understanding concerning the structure of grana thylakoids, the forces that contribute to their formation, and their architectural dynamics. After establishing the structural foundation, we will continue reviewing the implications of grana formation on light harvesting, electron transport, and protein maintenance in the thylakoid membranes of vascular plants. Regarding light harvesting, this review will discuss the implications of grana formation on energy spillover, macromolecular crowding, lateral versus vertical excitation energy transfer, and state transition. With respect to electron transport, we will summarize recent findings regarding the functional connectivity of spatially separated photosystems facilitated by grana formation through small mobile electron carriers. Furthermore, we will explore how the dynamic responses of grana architecture regulate electron transport. Finally, we will address how grana formation contributes to the organization of protein repair and biogenesis within thylakoid membranes.</p>","PeriodicalId":8023,"journal":{"name":"Annals of botany","volume":" ","pages":""},"PeriodicalIF":3.6,"publicationDate":"2025-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145091054","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Tracing the Evolution of Dicksoniaceae and Thyrsopteridaceae (Cyatheales) in South America: New Records from the Cretaceous.","authors":"Elizabeth J Hermsen, María A Gandolfo, N Rubén Cúneo, Facundo de Benedetti, María Del Carmen Zamaloa, Ignacio H Escapa","doi":"10.1093/aob/mcaf228","DOIUrl":"https://doi.org/10.1093/aob/mcaf228","url":null,"abstract":"<p><strong>Background and aims: </strong>Two new species of cyathealean ferns are described based on sterile and fertile frond fragments from the Cretaceous of Patagonia, Argentina. The new species are compared with other extant and extinct cyathealean ferns in Dicksoniaceae and Thyrsopteridaceae.</p><p><strong>Methods: </strong>The fern foliage macrofossils came from the Lower Cretaceous (Albian) Kachaike Formation, Santa Cruz Province, and the Upper Cretaceous (Maastrichtian) La Colonia Formation, Chubut Province. They were studied and photographed using standard techniques. Spores were also macerated from four fertile Kachaike Formation specimens and examined using light and scanning electron microscopy. Spores from a fertile La Colonia Formation specimen were described and figured in previous studies.</p><p><strong>Key results: </strong>The frond material from the Kachaike Formation is placed in the new species Dicksonia hallei; it is morphologically consistent with the modern genus Dicksonia, although its spores are distinct and conform to the dispersed spore species Cyathidites minor. The material from the La Colonia Formation cannot be placed in an existing genus and is assigned to the new genus and species Rhabdopteris chubutensis; its spores are also similar to the dispersed spore species Cyathidites minor. Cyathidites minor-type spores are known from several other Mesozoic cyathealean foliage taxa.</p><p><strong>Conclusions: </strong>Dicksonia hallei is currently the oldest credible macrofossil record of Dicksonia and Dicksoniaceae in South America, indicating that Dicksonia has been present on the continent at least since the Early Cretaceous. Because it has fertile pinnae and pinnules with highly reduced laminar tissue (skeletonized pinnae and pinnules) bearing Cyathidites minor-type spores, Rhabdopteris likely has affinities to the family Thyrsopteridaceae. The Thyrsopteridaceae have an extensive fossil record worldwide encompassing several fossil foliage genera.</p>","PeriodicalId":8023,"journal":{"name":"Annals of botany","volume":" ","pages":""},"PeriodicalIF":3.6,"publicationDate":"2025-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145091081","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Recruitment in Variable Environments: Plasticity and Bet-Hedging in the Timing of Seed Germination in Three Closely-Related Habitat Specialists.","authors":"Courtney L Van Den Elzen, Nancy C Emery","doi":"10.1093/aob/mcaf227","DOIUrl":"https://doi.org/10.1093/aob/mcaf227","url":null,"abstract":"<p><strong>Background and aims: </strong>Phenotypic plasticity and bet hedging are mechanisms that can facilitate population persistence in variable environments. In plants, the timing of seed germination can be responsive to reliable environmental cues as well as a mechanism for spreading risk when post-germination conditions are difficult to predict. The goal of this study was to quantify and compare plasticity and potential bet hedging in the timing of seed germination in three closely-related species that segregate across a fine-scale gradient in hydrological variability.</p><p><strong>Methods: </strong>We conducted a growth chamber experiment that measured variation in seed germination within and among three species of Lasthenia (Asteraceae) that occupy different microhabitats along gradients in soil moisture variability in California vernal pool grasslands. We measured the timing of germination in sibling seed groups from each species under two different moisture regimes to characterize the mean and variability in seed germination timing in response to consistent, high moisture and low, variable moisture conditions.</p><p><strong>Key results: </strong>Germination of viable seeds was extremely high (∼98%) across all species and treatments. All three taxa showed strong plasticity in response to water treatment by germinating faster with higher, more consistent moisture availability. The two species from higher topographic positions in vernal pool grasslands had greater within-season variance in germination timing, consistent with increased bet hedging, than the deep pool specialist. The extent of within-season bet hedging in these two species was largest in the drier and more variable water treatment, revealing phenotypic plasticity in the extent of bet hedging expressed by these species.</p><p><strong>Conclusions: </strong>This work supports the hypothesis that plasticity and bet hedging in seed germination timing are favored in variable and unpredictable environments, and that these strategies can evolve rapidly in association with habitat divergence among closely related species.</p>","PeriodicalId":8023,"journal":{"name":"Annals of botany","volume":" ","pages":""},"PeriodicalIF":3.6,"publicationDate":"2025-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145091065","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Seed dispersal as a backup system to resprouting and seeding during post-fire regeneration.","authors":"José M Costa, Ruben H Heleno, Pedro Lopes, Jaime A Ramos, Elizabete Marchante, Pablo Vargas, Sérgio Timóteo","doi":"10.1093/aob/mcaf230","DOIUrl":"https://doi.org/10.1093/aob/mcaf230","url":null,"abstract":"<p><strong>Background and aims: </strong>Plant populations can recover from wildfires through resprouting (resprouters), by recruiting from in situ surviving seed banks (seeders), or recolonization via seed dispersal. However, it is unclear how complementary these mechanisms can be, especially whether and how specific seed dispersal syndromes are associated with resprouter or seeder potential. In particular, it is unknown whether the occurrence of traits that facilitate seed dispersal and post-fire recolonization are disproportionately frequent among plants that lack other fire-coping strategies (i.e., colonizers).</p><p><strong>Methods: </strong>Here, we compiled information on the presence of post-fire regeneration mechanisms: resprouting potential, seeding capacity, and presence of traits that facilitate seed dispersal, for 705 species from the European Mediterranean Basin. Three-way contingency tables were built and analysed using log-linear models to assess associations between the three mechanisms.</p><p><strong>Key results: </strong>We found a negative association between resprouting and seeding capacity, and observed that these mechanisms were independent from having any traits related to seed dispersal. However, traits facilitating endozoochory (fleshy fruits) were more common among resprouters than expected by chance.</p><p><strong>Conclusions: </strong>Our results show that traits enhancing seed dispersal are widespread among post-fire resprouters and seeding species in the Mediterranean Basin flora. We conclude that seed dispersal traits are mostly an independent backup system assisting the recovery of burned sites rather than an alternative to resprouting or post-fire seeding.</p>","PeriodicalId":8023,"journal":{"name":"Annals of botany","volume":" ","pages":""},"PeriodicalIF":3.6,"publicationDate":"2025-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145091078","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Seed fatty acid composition and physical dormancy in fire-prone ecosystems.","authors":"Sarah J McInnes, Ryan Tangney, Mark K J Ooi","doi":"10.1093/aob/mcaf225","DOIUrl":"https://doi.org/10.1093/aob/mcaf225","url":null,"abstract":"<p><strong>Background and aims: </strong>The maintenance of seed banks and timing of germination are fundamental to ensuring population persistence. Physical dormancy (PY) in disturbance-prone environments contributes to these processes via an impermeable seed coat. Dormancy is broken often by heating, which in fire-prone regions is determined by species-specific threshold temperatures. However, the mechanisms by which seeds persist or control dormancy-breaking thresholds in such environments is unclear. We determined whether unsaturated and saturated fatty acids (FAs; within triacylglycerols), a common lipid linked to heat-stress resilience, might contribute to seed coat dormancy and overall seed persistence, and whether fire selects for different FA compositions and drives PY function in fire-prone regions.</p><p><strong>Methods: </strong>We characterised seed FA compositions of 26 Fabaceae species from fire-prone and fire-free ecosystems through gas chromatography-mass spectrometry. We compared FA saturation, total relative FA content and the highest melting point FA of each species across seed tissues (seed coat vs internal tissues) and habitat type (fire-prone vs fire-free) and, for fire-prone species, tested for a relationship with species-specific dormancy-breaking thresholds.</p><p><strong>Key results: </strong>No relationship between FA composition and species-specific dormancy-breaking thresholds was found. Seeds of fire-free species had more saturated FAs than fire-prone species, particularly for internal tissues. FA saturation was higher in seed coats than internal tissues across both habitat types. Relative FA content was similar in internal tissues across habitat type but differed for seed coats, with fire-prone species having marginally more FAs.</p><p><strong>Conclusions: </strong>While no correlation existed between FA composition and dormancy-breaking thresholds in fire-prone species, the consistent differences between seed tissue types we found highlights a similar role for FAs in seed coats across habitats, likely linked to maintaining impermeability. Some evidence supports fire selecting for greater total FA content in seed coats, however further work is needed to test its relationship with temperature thresholds.</p>","PeriodicalId":8023,"journal":{"name":"Annals of botany","volume":" ","pages":""},"PeriodicalIF":3.6,"publicationDate":"2025-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145091044","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Morphological innovation and lineage-specific history drive disparification in the aggregated pollen of mimosoid plants.","authors":"Rafael F Barduzzi, Stefany Liau-Kang, Ana Flávia Trabuco Duarte, Francisco de Assis Ribeiro Dos Santos, Leonardo M Borges","doi":"10.1093/aob/mcaf213","DOIUrl":"https://doi.org/10.1093/aob/mcaf213","url":null,"abstract":"<p><strong>Background and aims: </strong>The study of morphological diversity (i.e., disparity) offers unique opportunities to understand evolutionary patterns and processes. Plant disparity studies reveal that morphological disparification can be related to factors such as secondary woodiness or to pollination niche, for example. Similarly, some pollen traits are known to be shaped by environmental pressures, but this influence has only been evaluated in monads, never in multi-grained dispersal units. In this study, we investigated the disparity of aggregated dispersal units in two lineages of Neotropical mimosoid legumes. The Mimosa and Stryphnodendron clades are independent lineages that share similarities in pollen morphology and biome shifts. In this context, we asked: What are the patterns of pollen disparity in these lineages, and are these patterns similar between lineages occurring in the same biomes?</p><p><strong>Methods: </strong>To answer these questions, we compiled data from the literature on pollen morphology and biomes of occurrence for a phylogenetically representative set of taxa in the Mimosa and Stryphnodendron clades. With these data, we calculated morphospaces and disparity metrics, and tested whether the pollen morphology of distinct lineages occurring in the same biome differs significantly.</p><p><strong>Key results: </strong>Our results show that Mimosa and Stryphnodendron clades exhibit distinct patterns of pollen disparity, as do independent lineages occurring in the same biomes. Additionally, we observed that certain biomes support greater or lesser levels of morphological disparity.</p><p><strong>Conclusions: </strong>We conclude that (1) the Mimosa clade has greater disparity, possibly due to evolution of novel pollen morphologies in the genus Mimosa, (2) there is a maintenance of similarities in the pollen of the Stryphnodendron clade, Adenopodia and Piptadenia, and (3) the evolution of pollen grains in these groups appears to be primarily shaped by phylogeny and developmental constraints, with environmental pressures playing a comparatively smaller role.</p>","PeriodicalId":8023,"journal":{"name":"Annals of botany","volume":" ","pages":""},"PeriodicalIF":3.6,"publicationDate":"2025-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145091093","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Spinning together agricultural and evo-devo research for Gynandropsis gynandra (spider plant).","authors":"Brandi Zenchyzen, Jocelyn C Hall","doi":"10.1093/aob/mcaf205","DOIUrl":"https://doi.org/10.1093/aob/mcaf205","url":null,"abstract":"<p><strong>Background: </strong>Gynandropsis gynandra (Cleomaceae; formerly Cleome gynandra) is a leafy vegetable widely cultivated across Africa, uniquely positioned at the intersection of agricultural and evo-devo research. It is gaining recognition as an \"opportunity crop\", valued locally for its nutritional and medicinal properties with ongoing agricultural research aimed at the development of improved cultivars and agronomic practices. Concurrently, its close evolutionary proximity to Arabidopsis thaliana, combined with its contrasting traits, positions G. gynandra as a model for studying C₄ photosynthesis and floral development. Despite its relevance to both agricultural and evo-devo research, integration of findings between disciplines remains limited, hindered in part by inconsistent nomenclature and the lack of standardized morphological descriptors.</p><p><strong>Scope: </strong>To address this disconnect, this review synthesizes findings from agricultural and evo-devo research on G. gynandra. We provide an overview of its phylogenetic placement, geographical distribution, agricultural and medicinal applications, phytochemical profile, genomic and genetic resources, and morphological traits. In doing so, we emphasize the duality of G. gynandra as both a crop of agronomic interest and a model for evo-devo studies. Finally, we propose future research directions to promote cross-disciplinary collaboration and expedite progress in G. gynandra research.</p><p><strong>Conclusions: </strong>Advances in molecular tools have improved our understanding of the developmental mechanisms underlying key traits and physiological adaptations in G. gynandra, including C4 photosynthesis and antiherbivore defenses. Simultaneously, morphological studies have revealed distinctive floral features and substantial phenotypic diversity, offering valuable insights for both breeding initiatives and investigations into floral development. Integrating data and resources from agricultural and evo-devo research will accelerate the improvement of G. gynandra and broaden its utility as a model for understanding trait evolution and development.</p>","PeriodicalId":8023,"journal":{"name":"Annals of botany","volume":" ","pages":""},"PeriodicalIF":3.6,"publicationDate":"2025-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145091048","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Development of the embryo and ruminate endosperm in an early-divergent angiosperm, Asimina triloba (Annonaceae).","authors":"C Ferrer-Blanco, J I Hormaza, J Lora","doi":"10.1093/aob/mcaf026","DOIUrl":"10.1093/aob/mcaf026","url":null,"abstract":"<p><strong>Background and aims: </strong>Embryo and seed development are essential for the reproductive success of flowering plants. However, these processes remain underexplored in the family Annonaceae, which belongs to the early-divergent angiosperm Magnoliid clade, and is characterized by the distinctive feature of ruminations in the seeds. To fill this knowledge gap, we conducted a study to characterize the embryogeny and seed development of Asimina triloba ('pawpaw'), the northernmost species of the mainly tropical family Annonaceae.</p><p><strong>Methods: </strong>We performed a comprehensive histological examination of embryogeny in A. triloba, from fertilization to emergence of the embryo from the seed, in particular the formation of the ruminations in the endosperm.</p><p><strong>Key results: </strong>After a rapid fertilization process, the embryo develops slowly, which may support initial embryo development. Concomitant with this early embryogenesis, a ruminate nucellus develops as the main and primary storage tissue, which is later gradually replaced by the endosperm while still maintaining the ruminations. Finally, in the mature seed, the ruminate endosperm is consumed by the small and relatively underdeveloped embryo, which requires additional growth and development prior to germination.</p><p><strong>Conclusions: </strong>Our study provides a comprehensive overview of the stages from fertilization and early embryogenesis to seed germination of A. triloba. The results reveal both ancestral features, such as a slow embryogenesis and an underdeveloped embryo in the mature seed, and derived features, such as the presence of a ruminate endosperm, which is commonly found in the family Annonaceae. This combination of traits is also observed in other angiosperm families, suggesting a convergent evolutionary solution with adaptive significance, where a ruminate endosperm may evolve in response to specific environmental conditions. These findings contribute to a better understanding of both the diversity of embryological characters and their evolutionary significance across early-divergent and more derived angiosperm lineages.</p>","PeriodicalId":8023,"journal":{"name":"Annals of botany","volume":" ","pages":"297-308"},"PeriodicalIF":3.6,"publicationDate":"2025-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12445850/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143565849","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Homoploid hybrid speciation and recurrent hybridization along the northwestern Iberian mountain chains.","authors":"David Criado-Ruiz, Irene Villa-Machío, Rosalía Piñeiro, Jonathan F Wendel, Gonzalo Nieto Feliner","doi":"10.1093/aob/mcaf086","DOIUrl":"10.1093/aob/mcaf086","url":null,"abstract":"<p><strong>Background and aims: </strong>Natural hybridization can lead to diversification and adaptive introgression, among other outcomes. However, the mechanistic underpinnings of this process are insufficiently understood. A previous study of the Iberian endemic diploid genus Phalacrocarpum (Asteraceae, Anthemideae) identified several homoploid hybridization events and cryptic diversity, but raised questions regarding their evolutionary significance and specific genetic groups involved. This study aimed to clarify the evolutionary history of this genus.</p><p><strong>Methods: </strong>A double-digest restriction-site-associated DNA sequencing approach was used to generate nuclear single nucleotide polymorphisms (SNPs) from 261 samples of this genus and plastid sequences were obtained from 121 samples by genome skimming. Phylogenomic relationships were inferred from each of these two datasets. Bayesian genomic clustering analysis and ABBA-BABA tests were used to explore the population genetic structure and specific introgression hypotheses.</p><p><strong>Key results: </strong>Bayesian clustering analyses identified K = 34 as the best partition for the nuclear SNP data although about half of these groups are minimally represented in each sample and are shared across taxa. The suboptimal partition K = 7 supports the existence of seven lineages. In the nuclear phylogenomic tree, P. oppositifolium subsp. anomalum and subsp. hoffmannseggii are not monophyletic. The latter and the western group of subsp. anomalum consist of several small clades, each showing varying degrees of admixture. Comparison with the plastome tree reveals cytonuclear conflict affecting mainly two taxa, suggesting historical range shifts and different hybrid origins. ABBA-BABA tests found evidence of introgression, supporting the hybrid origin of the Galician-Portuguese border group, and multiple hybridization events between P. oppositifolium subsp. anomalum and subsp. hoffmannseggii.</p><p><strong>Conclusions: </strong>Multiple, partially recurrent, hybridization events, occurring mainly along an L-shaped mountain corridor from the eastern Cantabrian range to the Serra da Estrela in central Portugal, have shaped the genetic structure of Phalacrocarpum diversity. A part of these events has resulted in three homoploid hybrid lineages, which are incipient hybrid species.</p>","PeriodicalId":8023,"journal":{"name":"Annals of botany","volume":" ","pages":"325-342"},"PeriodicalIF":3.6,"publicationDate":"2025-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12445855/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143966334","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}