A stepwise route to domesticate rice by controlling seed shattering and panicle shape.

Asian rice (Oryza sativa L.) is consumed by more than half of the world's population. Despite its global importance, the process of early rice domestication remains unclear. During domestication, wild rice (Oryza rufipogon Griff.) acquired non-seed-shattering behavior, allowing humans to increase grain yield. Previous studies argued that a reduction in seed shattering triggered by the sh4 mutation led to increased yield during rice domestication, but our experiments using wild introgression lines show that the domesticated sh4 allele alone is insufficient for shattering loss in O. rufipogon. The interruption of abscission layer formation requires both sh4 and qSH3 mutations, demonstrating that the selection of shattering loss in wild rice was not as simple as previously suggested. Here we identified a causal single-nucleotide polymorphism at qSH3 within the seed-shattering gene OsSh1, which is conserved in indica and japonica subspecies but absent in the circum-aus group of rice. Through harvest experiments, we further demonstrated that seed shattering alone did not significantly impact yield; rather, yield increases were observed with closed panicle formation controlled by SPR3 and further augmented by nonshattering, conferred by integration of sh4 and qSH3 alleles. Complementary manipulation of panicle shape and seed shattering results in a mechanically stable panicle structure. We propose a stepwise route for the earliest phase of rice domestication, wherein selection of visible SPR3-controlled closed panicle morphology was instrumental in the sequential recruitment of sh4 and qSH3, which together led to the loss of shattering.

Contrasting genetic signal of recolonization after rainforest fragmentation in African trees with different dispersal abilities.

Although today the forest cover is continuous in Central Africa, this may have not always been the case, as the scarce fossil record in this region suggests that arid conditions might have significantly reduced tree density during the ice ages. Our aim was to investigate whether the dry ice age periods left a genetic signature on tree species that can be used to infer the date of the past fragmentation of the rainforest. We sequenced reduced representation libraries of 182 samples representing five widespread legume trees and seven outgroups. Phylogenetic analyses identified an early divergent lineage for all species in West Africa (Upper Guinea) and two clades in Central Africa: Lower Guinea-North and Lower Guinea-South. As the structure separating the Northern and Southern clades-congruent across species-cannot be explained by geographic barriers, we tested other hypotheses with demographic model testing using δαδι. The best estimates indicate that the two clades split between the Upper Pliocene and the Pleistocene, a date compatible with forest fragmentation driven by ice age climatic oscillations. Furthermore, we found remarkably older split dates for the shade-tolerant tree species with nonassisted seed dispersal than for light-demanding species with long-distance wind-dispersed seeds. Different recolonization abilities after recurrent cycles of forest fragmentation seem to explain why species with long-distance dispersal show more recent genetic admixture between the two clades than species with limited seed dispersal. Despite their old history, our results depict the African rainforests as a dynamic biome where tree species have expanded relatively recently after the last glaciation.

Spatiotemporal process of long-distance seed dispersal in a pantropically distributed sea hibiscus group.

Long-distance dispersal (LDD) of seeds plays an essential role in the migration of plants to a new habitat and maintaining gene flow among geographically isolated populations. Pantropical plants with sea-drifted seeds, which have one of the largest distributions in all flowering plants, have achieved their global distribution by LDD. However, the spatiotemporal processes to achieve the wide distribution and the role of LDD in it have not yet been elucidated. In this study, we conducted phylogenomic analyses on the plastome, genome-wide nuclear SNP, and low-copy gene data of Hibiscus tiliaceus and its relatives. The dated phylogeny suggested that global expansion started approximately 4 million years ago (Ma), and species diversification occurred 1 Ma. Plastome phylogeny confirmed the nonmonophyly of the haplotypes in the two widely distributed coastal species, H. tiliaceus and H. pernambucensis. In contrast, genome-wide nuclear SNP phylogenies demonstrated clear genetic segregation among species and/or geographical regions. Ancestral polymorphisms in chloroplast genomes shared among widely distributed species have remained below the range of rapid expansion and speciation of marginal populations. This study demonstrated that the LDD of sea-drifted seeds contributed to the rapid expansion and pantropical distribution of sea hibiscus in the last few million years, and adaptation to local environment or isolation by regional effect after LDD promoted speciation, suppressing gene flow.

Population genetic structure and connectivity of a riparian selfing herb Caulokaempferia coenobialis at a fine-scale geographic level in subtropical monsoon forest.

BACKGROUND: Rivers and streams facilitate movement of individuals and their genes across the landscape and are generally recognized as dispersal corridors for riparian plants. Nevertheless, some authors have reported directly contrasting results, which may be attributed to a complex mixture of factors, such as the mating system and dispersal mechanisms of propagules (seed and pollen), that make it difficult to predict the genetic diversity and population structure of riparian species. Here, we investigated a riparian self-fertilizing herb Caulokaempferia coenobialis, which does not use anemochory or zoochory for seed dispersal; such studies could contribute to an improved understanding of the effect of rivers or streams on population genetic diversity and structure in riparian plants. Using polymorphic ISSR and cpDNA loci, we studied the effect at a microgeographic scale of different stream systems (a linear stream, a dendritic stream, and complex transverse hydrological system) in subtropical monsoon forest on the genetic structure and connectivity of C. coenobialis populations across Dinghu Mountain (DH) and Nankun Mountain (NK). RESULTS: The results indicate that the most recent haplotypes (DH: H7, H8; NK: h6, h7, h11, h12) are not shared among local populations of C. coenobialis within each stream system. Furthermore, downstream local populations do not accumulate genetic diversity, whether in the linear streamside local populations across DH (H: 0.091 vs 0.136) or the dendritic streamside local populations across NK (H: 0.079 vs 0.112, 0.110). Our results show that the connectivity of local C. coenobialis populations across DH and NK can be attributed to historical gene flows, resulting in a lack of spatial genetic structure, despite self-fertilization. Selfing C. coenobialis can maintain high genetic diversity (H = 0.251; I = 0.382) through genetic differentiation (GST = 0.5915; FST = 0.663), which is intensified by local adaptation and neutral mutation and/or genetic drift in local populations at a microgeographic scale. CONCLUSION: We suggest that streams are not acting as corridors for dispersal of C. coenobialis, and conservation strategies for maintaining genetic diversity of selfing species should be focused on the protection of all habitat types, especially isolated fragments in ecosystem processes.

Dispersal as a result of asymmetrical hybridization between two closely related oak species in China.

Hybridization has played an important role in plant evolution. Less attention has been paid, however, to its role in dispersal. In this study, historical divergence and hybridization were investigated in two closely related Chinese oaks, Quercus mongolica and Q. liaotungensis, to estimate the role that hybridization played in their dispersal. We genotyped 27 Q. mongolica and Q. liaotungensis populations throughout the distributional range of the two oak species, using 14 single-copy nuclear genes and four noncoding chloroplast DNA regions. Bayesian cluster and population tree analyses indicated that there were three groups over all oak populations, namely, Q. mongolica, northwest-northern China (NW-NC) Q. liaotungensis, and northeastern China (NEC) Q. liaotungensis. Approximate Bayesian computation simulation supported an asymmetrical hybridization origin of NEC Q. liaotungensis, after a previous divergence between NW-NC Q. liaotungensis and Q. mongolica. IMa3 analyses suggested that Q. liaotungensis and Q. mongolica diverged in the NW-NC and NEC regions, respectively, and that NEC Q. liaotungensis arose from Q. mongolica, not from NW-NC Q. liaotungensis, and was greatly introgressed by NW-NC Q. liaotungensis. Oak populations in NW-NC and NEC regions held different chloroplast DNA haplotypes, and Q. liaotungensis in NEC shared most haplotypes with Q. mongolica populations, but none with NW-NC Q. liaotungensis populations, suggesting the maternal origin of NEC Q. liaotungensis from Q. mongolica. This study found clear signals of isolation divergence of Q. liaotungensis in NW-NC and Q. mongolica in NEC, and the results suggest that asymmetrical hybridization and introgression from Q. liaotungensis to Q. mongolica, mostly likely via pollen flow, facilitated Q. liaotungensis dispersal to NEC.

Associated evolution of fruit size, fruit colour and spines in Neotropical palms.

Understanding how ecological interactions have shaped the evolutionary dynamics of species traits remains a challenge in evolutionary ecology. Combining trait evolution models and phylogenies, we analysed the evolution of characters associated with seed dispersal (fruit size and colour) and herbivory (spines) in Neotropical palms to infer the role of these opposing animal-plant interactions in driving evolutionary patterns. We found that the evolution of fruit colour and fruit size was associated in Neotropical palms, supporting the adaptive interpretation of seed-dispersal syndromes and highlighting the role of frugivores in shaping plant evolution. Furthermore, we revealed a positive association between fruit size and the presence of spines on palm leaves, bracteas and stems. We hypothesize that interactions between palms and large-bodied frugivores/herbivores may explain the evolutionary relationship between fruit size and spines. Large-bodied frugivores, such as extinct megafauna, besides consuming the fruits and dispersing large seeds, may also have consumed the leaves or damaged the plants, thus simultaneously favouring the evolution of large fruits and defensive structures. Our findings show how current trait patterns can be understood as the result of the interplay between antagonistic and mutualistic interactions that have happened throughout the evolutionary history of a clade.

Seed abscission and fruit dehiscence required for seed dispersal rely on similar genetic networks.

Seed dispersal is an essential trait that enables colonization of new favorable habitats, ensuring species survival. In plants with dehiscent fruits, such as Arabidopsis, seed dispersal depends on two processes: the separation of the fruit valves that protect the seeds (fruit dehiscence) and the detachment of the seeds from the funiculus connecting them to the mother plant (seed abscission). The key factors required to establish a proper lignin pattern for fruit dehiscence are SHATTERPROOF 1 and 2 (SHP1 and SHP2). Here, we demonstrate that the SHP-related gene SEEDSTICK (STK) is a key factor required to establish the proper lignin pattern in the seed abscission zone but in an opposite way. We show that STK acts as a repressor of lignin deposition in the seed abscission zone through the direct repression of HECATE3, whereas the SHP proteins promote lignin deposition in the valve margins by activating INDEHISCENT. The interaction of STK with the SEUSS co-repressor determines the difference in the way STK and SHP proteins control the lignification patterns. Despite this difference in the molecular control of lignification during seed abscission and fruit dehiscence, we show that the genetic networks regulating these two developmental pathways are highly conserved.

Seed and pollen dispersal distances in two African legume timber trees and their reproductive potential under selective logging.

The natural regeneration of tree species depends on seed and pollen dispersal. To assess whether limited dispersal could be critical for the sustainability of selective logging practices, we performed parentage analyses in two Central African legume canopy species displaying contrasted floral and fruit traits: Distemonanthus benthamianus and Erythrophleum suaveolens. We also developed new tools linking forward dispersal kernels with backward migration rates to better characterize long-distance dispersal. Much longer pollen dispersal in D. benthamianus (mean distance dp  = 700 m, mp  = 52% immigration rate in 6 km2 plot, s = 7% selfing rate) than in E. suaveolens (dp  = 294 m, mp  = 22% in 2 km2 plot, s = 20%) might reflect different insect pollinators. At a local scale, secondary seed dispersal by vertebrates led to larger seed dispersal distances in the barochorous E. suaveolens (ds  = 175 m) than in the wind-dispersed D. benthamianus (ds  = 71 m). Yet, seed dispersal appeared much more fat-tailed in the latter species (15%-25% seeds dispersing >500 m), putatively due to storm winds (papery pods). The reproductive success was correlated to trunk diameter in E. suaveolens and crown dominance in D. benthamianus. Contrary to D. benthamianus, E. suaveolens underwent significant assortative mating, increasing further the already high inbreeding of its juveniles due to selfing, which seems offset by strong inbreeding depression. To achieve sustainable exploitation, seed and pollen dispersal distances did not appear limiting, but the natural regeneration of E. suaveolens might become insufficient if all trees above the minimum legal cutting diameter were exploited. This highlights the importance of assessing the diameter structure of reproductive trees for logged species.

Phylotranscriptomics resolves interspecific relationships and indicates multiple historical out-of-North America dispersals through the Bering Land Bridge for the genus Picea (Pinaceae).

A robust phylogeny is prerequisite to understand the evolution and biogeography of organisms. However, ancient and recent evolutionary radiations occurred in many plant lineages, which pose great challenges for phylogenetic analysis, especially for conifers characterized by large effective population sizes and long generation times. Picea is an important component of the dark coniferous forests in the Northern Hemisphere. Previous studies improved our understanding of its evolutionary history, but its interspecific relationships and biogeographic history remain largely unresolved. In the present study, we reconstructed a well-resolved phylogeny of Picea by comparative transcriptomic analysis based on a complete species sampling. The phylogenetic analysis, together with molecular dating and ancestral area reconstruction, further supports the North American origin hypothesis for Picea, and indicates that this genus experienced multiple out-of-North America dispersals by the Bering Land Bridge. We also found that spruces in the Japanese Archipelago have multiple origins, and P. morrisonicola from the Taiwan Island has a close relationship with species from the Qinghai-Tibetan Plateau and adjacent regions. Our study provides the first complete phylogeny of Picea at the genomic level, which is important for future studies of this genus.

Placing the regionally threatened moss Orthodontium gracile in the big picture - Phylogeny, genome incongruence and anthropogenic dispersal in the order Orthodontiales.

The Orthodontiaceae is a small family of predominantly Southern Hemisphere temperate and South East Asian mosses that has a key phylogenetic position for research into the evolution of pleurocarpy. In the United Kingdom it is represented by the rare conservation priority species Orthodontium gracile and the abundant exotic O. lineare, introduced from the Southern Hemisphere around a century ago. Although the two species are superficially very similar and difficult to tell apart in the field, very little is known about how closely they are related or about the phylogeny, biogeography and evolutionary history of the genus Orthodontium as a whole. Phylogenetic inference and divergence time estimation were used to explore relationships within the genus globally, date major lineage splits, detect reticulate evolutionary processes and test monophyly of taxa. It was shown that Orthodontium gracile belongs to a Holarctic and Asian clade that diverged from the exclusively southern temperate lineage of O. lineare approximately 53 Ma and that it is sister to the Himalayan and South Siberian bispecific genus Orthodontopsis, which we now recognise as a single species within Orthodontium, O. lignicola. Orthodontium lignicola is quite distinct from O. gracile morphologically but may have a closely overlapping centre of extant diversity in the Himalaya, in contrast to O. lineare which is morphologically similar but biogeographically dissimilar. The introduced European populations of Orthodontium lineare were shown to share plastid and nuclear haplotypes with four collections from Tasmania and Southern Chile, but to be distinct from other Chilean and South African haplotypes. Finally, well-supported incongruence between nuclear and plastid sequences in some Western North American populations of Orthodontium gracile strongly implies one or more chloroplast capture or horizontal genome transfer events involving this species and the regionally sympatric O. pellucens. An appeal is made for targeting phylogenetic research at the intersection points of practical conservation, taxonomic uncertainty and wider biological questions and for the factoring of historical evolutionary and phylogenetic diversity into conservation assessments.

Complex fine-scale spatial genetic structure in Epidendrum rhopalostele: an epiphytic orchid.

Orchid seeds are presumably dispersed by wind due to their very small size and thus can potentially travel long distances. However, the few related studies indicate that seeds fall close to their mother plants. Because seed dispersal and colonization patterns can have relevant consequences for long-term species persistence, we assessed the fine-scale genetic structure of the epiphytic orchid Epidendrum rhopalostele to provide insight into these patterns. All individuals in the studied population were georeferenced and genotyped with AFLP-markers. Genetic structure was evaluated at two levels (forest and tree) using three approaches: principal coordinates analysis, model-based clustering, and spatial autocorrelation analysis. Results showed two genetic groups, composed of individuals from almost every tree with orchids. Spatial autocorrelation analysis at the forest level found no significant genetic structure when all individuals were considered, but a pattern of genetic patches was revealed when the analysis was performed separately for each group. Genetic patches had an estimated diameter of 4 m and were composed of individuals from more than one tree. A weak genetic structure was detected at the tree level at distances less than 1.5 m. These results suggest that many seeds fall close to the mother plant and become established in the same host tree. Additionally, a sequential colonization process seems to be the predominant mode of expansion, whereby progeny from orchids in one tree colonize neighboring trees. Thus, the existence of two distinct genetic groups and the presence of genetic patches should be considered when seed sampling for ex situ conservation.

Rare genotype advantage promotes survival and genetic diversity of a tropical palm.

Negative density dependence, where survival decreases as density increases, is a well-established driver of species diversity at the community level, but the degree to which a similar process might act on the density or frequency of genotypes within a single plant species to maintain genetic diversity has not been well studied in natural systems. In this study, we determined the maternal genotype of naturally dispersed seeds of the palm Oenocarpus bataua within a tropical forest in northwest Ecuador, tracked the recruitment of each seed, and assessed the role of individual-level genotypic rarity on survival. We demonstrate that negative frequency-dependent selection within this species conferred a survival advantage to rare maternal genotypes and promoted population-level genetic diversity. The strength of the observed rare genotype survival advantage was comparable to the effect of conspecific density regardless of genotype. These findings corroborate an earlier, experimental study and implicate negative frequency-dependent selection of genotypes as an important, but currently underappreciated, determinant of plant recruitment and within-species genetic diversity. Incorporating intraspecific genetic variation into studies and theory of forest dynamics may improve our ability to understand and manage forests, and the processes that maintain their diversity.

Habitat loss and fragmentation reduce effective gene flow by disrupting seed dispersal in a neotropical palm.

Habitat loss and fragmentation often reduce gene flow and genetic diversity in plants by disrupting the movement of pollen and seed. However, direct comparisons of the contributions of pollen vs. seed dispersal to genetic variation in fragmented landscapes are lacking. To address this knowledge gap, we partitioned the genetic diversity contributed by male gametes from pollen sources and female gametes from seed sources within established seedlings of the palm Oenocarpus bataua in forest fragments and continuous forest in northwest Ecuador. This approach allowed us to quantify the separate contributions of each of these two dispersal processes to genetic variation. Compared to continuous forest, fragments had stronger spatial genetic structure, especially among female gametes, and reduced effective population sizes. We found that within and among fragments, allelic diversity was lower and genetic structure higher for female gametes than for male gametes. Moreover, female gametic allelic diversity in fragments decreased with decreasing surrounding forest cover, while male gametic allelic diversity did not. These results indicate that limited seed dispersal within and among fragments restricts genetic diversity and strengthens genetic structure in this system. Although pollen movement may also be impacted by habitat loss and fragmentation, it nonetheless serves to promote gene flow and diversity within and among fragments. Pollen and seed dispersal play distinctive roles in determining patterns of genetic variation in fragmented landscapes, and maintaining the integrity of both dispersal processes will be critical to managing and conserving genetic variation in the face of continuing habitat loss and fragmentation in tropical landscapes.

The relative contributions of seed and pollen dispersal to gene flow and genetic diversity in seedlings of a tropical palm.

Seed and pollen dispersal shape patterns of gene flow and genetic diversity in plants. Pollen is generally thought to travel longer distances than seeds, but seeds determine the ultimate location of gametes. Resolving how interactions between these two dispersal processes shape microevolutionary processes is a long-standing research priority. We unambiguously isolated the separate and combined contributions of these two dispersal processes in seedlings of the animal-dispersed palm Oenocarpus bataua to address two questions. First, what is the spatial extent of pollen versus seed movement in a system characterized by long-distance seed dispersal? Second, how does seed dispersal mediate seedling genetic diversity? Despite evidence of frequent long-distance seed dispersal, we found that pollen moves much further than seeds. Nonetheless, seed dispersal ultimately mediates genetic diversity and fine-scale spatial genetic structure. Compared to undispersed seedlings, seedlings dispersed by vertebrates were characterized by higher female gametic and diploid seedling diversity and weaker fine-scale spatial genetic structure for female gametes, male gametes and diploid seedlings. Interestingly, the diversity of maternal seed sources at seed deposition sites (Nem ) was associated with higher effective number of pollen sources (Nep ), higher effective number of parents (Ne ) and weaker spatial genetic structure, whereas seed dispersal distance had little impact on these or other parameters we measured. These findings highlight the importance maternal seed source diversity (Nem ) at frugivore seed deposition sites in driving emergent patterns of fine-scale genetic diversity and structure.

Isolation by distance and stochastic migration in a fragmented population of Prosopis alba.

PREMISE OF THE STUDY: Gene flow through dispersal of seeds and pollen is a fundamental determinant of spatial genetic structure (SGS) in natural populations of trees at different spatial scales. Within continuous populations, restrictions to gene flow should be manifested in a process of local genetic differentiation, known as isolation by distance. The present work examines the SGS of a Prosopis alba population in a patchy region where urban, forest, and agricultural areas coexist. The analysis discussed here expands our knowledge about the processes affecting the distribution of the genetic variability in populations of disturbed landscapes. METHODS: Three sites with different landscape and demographic characteristics were analyzed. Seven highly variable microsatellite markers were used to survey the relevance of both isolation by distance and stochastic migration in the SGS of the population. KEY RESULTS: The analyses showed that (1) the genetic similarity declined with increasing geographic distance, (2) the population may be conceived as a single genetically continuous unit showing spatial differentiation as consequence of isolation by distance, rather than a structured population following the island model, and (3) there is evidence supporting a past immigration event into one of the study sites, which promoted a local pattern of genetic structure. CONCLUSIONS: These results indicate that in spite of the population fragmentation produced by land-use changes, P. alba maintains the genetic cohesion and a continuous genetic structure in the analyzed area.

Molecular basis of a shattering resistance boosting global dissemination of soybean.

Pod dehiscence (shattering) is essential for the propagation of wild plant species bearing seeds in pods but is a major cause of yield loss in legume and crucifer crops. Although natural genetic variation in pod dehiscence has been, and will be, useful for plant breeding, little is known about the molecular genetic basis of shattering resistance in crops. Therefore, we performed map-based cloning to unveil a major quantitative trait locus (QTL) controlling pod dehiscence in soybean. Fine mapping and complementation testing revealed that the QTL encodes a dirigent-like protein, designated as Pdh1. The gene for the shattering-resistant genotype, pdh1, was defective, having a premature stop codon. The functional gene, Pdh1, was highly expressed in the lignin-rich inner sclerenchyma of pod walls, especially at the stage of initiation in lignin deposition. Comparisons of near-isogenic lines indicated that Pdh1 promotes pod dehiscence by increasing the torsion of dried pod walls, which serves as a driving force for pod dehiscence under low humidity. A survey of soybean germplasm revealed that pdh1 was frequently detected in landraces from semiarid regions and has been extensively used for breeding in North America, the world's leading soybean producer. These findings point to a new mechanism for pod dehiscence involving the dirigent protein family and suggest that pdh1 has played a crucial role in the global expansion of soybean cultivation. Furthermore, the orthologs of pdh1, or genes with the same role, will possibly be useful for crop improvement.

Phylogenetic investigation of the complex evolutionary history of dispersal mode and diversification rates across living and fossil Fagales.

As a primary determinant of spatial structure in angiosperm populations, fruit dispersal may impact large-scale ecological and evolutionary processes. Essential to understanding these mechanisms is an accurate reconstruction of dispersal mode over the entire history of an angiosperm lineage. A total-evidence phylogeny is presented for most fossil fruit and all extant genera in Fagales over its c. 95 million yr history. This phylogeny - the largest of its kind to include plant fossils - was used to reconstruct an evolutionary history directly informed by fossil morphologies and to assess relationships among dispersal mode, biogeographic range size, and diversification rate. Reconstructions indicate four transitions to wind dispersal and seven to biotic dispersal, with the phylogenetic integration of fossils crucial to understanding these patterns. Complexity further increased when more specialized behaviors were considered, with fluttering, gliding, autorotating, and scatter-hoarding evolving multiple times across the order. Preliminary biogeographic analyses suggest larger range sizes in biotically dispersed lineages, especially when pollination mode was held constant. Biotically dispersed lineages had significantly higher diversification rates than abiotically dispersed lineages, although transitions in dispersal mode alone cannot explain all detected diversification rate shifts across Fagales.

A phylogenetic study of the tribe Antirrhineae: Genome duplications and long-distance dispersals from the Old World to the New World.

PREMISE OF THE STUDY: Antirrhineae is a large tribe within Plantaginaceae. Mostly concentrated in the Mediterranean Basin, the tribe members are present both in the Old World and the New World. Current Antirrhineae phylogenies have different views on taxonomic relationships, and they lack homogeneity in terms of geographic distribution and ploidy levels. This study aims to investigate the changes in the chromosome numbers along with dispersal routes as definitive characters identifying clades. METHODS: With the use of multiple DNA regions and taxon sampling enriched with de novo sequences, we provide an extensive phylogeny for Antirrhineae. The reconstructed phylogeny was then used to investigate changes in ploidy levels and dispersal patterns in the tribe using ChromEvol and RASP, respectively. KEY RESULTS: Antirrhineae is a monophyletic group with six highly supported clades. ChromEvol analysis suggests the ancestral haploid chromosome number for the tribe is six, and that the tribe has experienced several duplications and gain events. The Mediterranean Basin was estimated to be the origin for the tribe with four long-distance dispersals from the Old World to the New World, three of which were associated with genome duplications. CONCLUSIONS: On an updated Antirrhineae phylogeny, we showed that the three out of four dispersals from the Old World to the New World were coupled with changes in ploidy levels. The observed patterns suggest that increases in ploidy levels may facilitate dispersing into new environments.

An optimised protocol to isolate high-quality genomic DNA from seed tissues streamlines the workflow to obtain direct estimates of seed dispersal distances in gymnosperms.

Genotyping of maternally derived seed tissues from georefered seeds that moved away from their source tree yield direct estimates of seed dispersal distances when the location and the genotype of the fruiting tree are available. These estimates are instrumental in forecasting the response of plant communities to drivers of global change, such as fragmentation or the expansion of invasive species. Obtaining robust assessments of seed dispersal distances requires comparing reliable multilocus genotypes of maternally derived seed tissues and fruiting trees, as previously shown for angiosperm species. However, robust estimates of seed dispersal distances based on direct methods are rare in non-model gymnosperms due to the difficulty in isolating high quality DNA from inconspicuous maternally derived seed tissues. These tissues tend to yield low DNA quantities that increase the frequency of genotyping errors. Here, we deliver a step-by-step visual protocol used to identify and isolate different seed tissues of interest for dispersal studies: embryos (2n, bi-parentally derived), seed coats (2n, maternally derived), and megagametophytes (n, maternally derived). We also provide an optimised lab protocol used to obtain multilocus genotypes from the target seed tissue. These broadly applicable protocols proved successful both in avoiding contamination among different seed tissues and providing reliable multilocus genotypes.

Patterns of gene flow in Encholirium horridum L.B.Sm., a monocarpic species of Bromeliaceae from Brazil.

Encholirium horridum is a bromeliad that occurs exclusively on inselbergs in the Atlantic Forest biome of Brazil. These rock outcrops form natural islands that isolate populations from each other. We investigated gene flow by pollen through paternity analyses of a bromeliad population in an area of approximately 2 ha in Espírito Santo State, Brazil. To that end, seed rosettes and seedlings were genotyped using nuclear microsatellite loci. A plot was also established from the same population and specimens were genotyped to evaluate their fine-scale spatial genetic structure (SGS) through analyses of spatial autocorrelation and clonal growth. Paternity analysis indicated that 80% of the attributed progenitors of the genotyped seedlings were from inside the study area. The pollen dispersal distances within the area were restricted (mean distance of 45.5 m, varying from 3 to 156 m) and fine-scale SGS was weak (F(ij) = 0.0122, P < 0.001; Sp = 0.009). Clonal growth was found to be a rare event, supporting the monocarpy of this species.