Phylogenetics of Puya (Bromeliaceae): Placement, major lineages, and evolution of Chilean species

Floral pigments and their perception by avian pollinators in three Chilean Puya species

The Chilean Puya species, Puya coerulea var. violacea and P. chilensis bear blue and pale-yellow flowers, respectively, while P. alpestris considered to be their hybrid-derived species has unique turquoise flowers. In this study, the chemical basis underlying the different coloration of the three Puya species was explored. We first isolated and identified three anthocyanins: delphinidin 3,3',5'-tri-O-glucoside, delphinidin 3,3'-di-O-glucoside and delphinidin 3-O-glucoside; seven flavonols: quercetin 3-O-rutinoside-3'-O-glucoside, quercetin 3,3'-di-O-glucoside, quercetin 3-O-rutinoside, isorhamnetin 3-O-rutinoside, myricetin 3,3',5'-tri-O-glucoside, myricetin 3,3'-di-O-glucoside and laricitrin 3,5'-di-O-glucoside; and six flavones: luteolin 4'-O-glucoside, apigenin 4'-O-glucoside, tricetin 4'-O-glucoside, tricetin 3',5'-di-O-glucoside, tricetin 3'-O-glucoside and selagin 5'-O-glucoside, which is a previously undescribed flavone, from their petals. We also compared compositions of floral flavonoid and their aglycone among these species, which suggested that the turquoise species P. alpestris has an essentially intermediate composition between the blue and pale-yellow species. The vacuolar pH was relatively higher in the turquoise (pH 6.2) and pale-yellow (pH 6.2) flower species, while that of blue flower species was usual (pH 5.2). The flower color was reconstructed in vitro using isolated anthocyanin, flavonol and flavone at neutral and acidic pH, and its color was analyzed by reflectance spectra and the visual modeling of their avian pollinators. The modeling demonstrated that the higher pH of the turquoise and pale-yellow species enhances the chromatic contrast and spectral purity. The precise regulation of flower color by flavonoid composition and vacuolar pH may be adapted to the visual perception of their avian pollinator vision.

Ecogeography of Dioscorea remotiflora Kunth: An Endemic Species from Mexico

Dioscorea remotiflora, a perennial climbing herbaceous plant native to Mexico, produces tubers with great nutritional and ethnobotanical value. However, most ecological aspects of this plant remain unknown, which limits its cultivation and use. This is why the objective of this research was to characterize the ecogeography of D. remotiflora as a source to determine its edaphoclimatic adaptability and current and potential distribution. A comprehensive database encompassing 480 geo-referenced accessions was assembled from different data sources. Using the Agroclimatic Information System for México and Central America (SIAMEXCA), 42 environmental variables were formulated. The MaxEnt model within the Kuenm R package was employed to predict the species distribution. The findings reveal a greater presence of D. remotiflora in harsh environments, characterized by arid to semiarid conditions, poor soils, and hot climates with long dry periods. Niche modeling revealed that seven key variables determine the geographical distribution of D. remotiflora: precipitation of the warmest quarter, precipitation of the driest month, minimum temperature of the coldest month, November-April solar radiation, annual mean relative humidity, annual moisture availability index, and May-October mean temperature. The current potential distribution of D. remotiflora is 428,747.68 km2. Favorable regions for D. remotiflora coincide with its current presence sites, while other suitable areas, such as the Yucatán Peninsula, northeast region, and Gulf of Mexico, offer potential expansion opportunities for the species distribution. The comprehensive characterization of Dioscorea remotiflora, encompassing aspects such as its soil habitats and climate adaptation, becomes essential not only for understanding its ecology but also for maximizing its economic potential. This will enable not only its sustainable use but also the exploration of commercial applications in sectors such as the pharmaceutical and food industries, thus providing a broader approach for its conservation and optimal utilization in the near future.

Genetic markers in Andean Puya species (Bromeliaceae) with implications on plastome evolution and phylogeny

The Andean plant endemic Puya is a striking example of recent and rapid diversification from central Chile to the northern Andes, tracking mountain uplift. This study generated 12 complete plastomes representing nine Puya species and compared them to five published plastomes for their features, genomic evolution, and phylogeny. The total size of the Puya plastomes ranged from 159,542 to 159,839 bp with 37.3%–37.4% GC content. The Puya plastomes were highly conserved in organization and structure with a typical quadripartite genome structure. Each of the 17 consensus plastomes harbored 133 genes, including 87 protein‐coding genes, 38 tRNA (transfer RNA) genes, and eight rRNA (ribosomal RNA) genes; we found 69–78 tandem repeats, 45–60 SSRs (simple sequence repeats), and 8–22 repeat structures among 13 species. Four protein‐coding genes were identified under positive site‐specific selection in Puya. The complete plastomes and hypervariable regions collectively provided pronounced species discrimination in Puya and a practical tool for future phylogenetic studies. The reconstructed phylogeny and estimated divergence time for the lineage suggest that the diversification of Puya is related to Andean orogeny and Pleistocene climatic oscillations. This study provides plastome resources for species delimitation and novel phylogenetic and biogeographic studies.

Cytotoxic Effect of Puya chilensis Collected in Central Chile

This study sought to evaluate the pharmacological activity of metabolites isolated from the dried and lyophilized ethanol extracts as well as other solvent fractions of the currently endangered Puya chilensis Molina (Chagual) by analyzing their effects on a human hepatocellular carcinoma (HCC) cell line. We identified several active metabolites from Chagual extracts and two, in particular, carnosol, were found in all the prepared fractions. In addition, Chagual exhibited considerable cytotoxicity against the cancer cell line used in this study, with a half-maximal inhibitory concentration (IC50) of 0.44 ± 0.11 and 0.27 ± 0.04 after a 72-hour treatment and, therefore, has the potential for further investigation as a source of candidate therapeutic agents.

Draft genome of Puya raimondii (Bromeliaceae), the Queen of the Andes

Puya raimondii, the Queen of the Andes, is an endangered high Andean species in the Bromeliaceae family. Here, we report its first genome to promote its conservation and evolutionary study. Comparative genomics showed P. raimondii diverged from Ananas comosus about 14.8 million years ago, and the long terminal repeats were likely to contribute to the genus diversification in last 3.5 million years. The gene families related to plant reproductive development and stress responses significantly expanded in the genome. At the same time, gene families involved in disease defense, photosynthesis and carbohydrate metabolism significantly contracted, which may be an evolutionary strategy to adapt to the harsh conditions in high Andes. The demographic history analysis revealed the P. raimondii population size sharply declined in the Pleistocene and then increased in the Holocene. We also designed and tested 46 pairs of universal primers for amplifying orthologous single-copy nuclear genes in Puya species.

Genome Skimming Reveals Widespread Hybridization in a Neotropical Flowering Plant Radiation

The tropics hold at least an order of magnitude greater plant diversity than the temperate zone, yet the reasons for this difference are still subject to debate. Much of tropical plant diversity is in highly speciose genera and understanding the drivers of such high species richness will help solve the tropical diversity enigma. Hybridization has recently been shown to underlie many adaptive radiations, but its role in the evolution of speciose tropical plant genera has received little attention. Here, we address this topic in the hyperdiverse Bromeliaceae genus Vriesea using genome skimming data covering the three genomic compartments. We find evidence for hybridization in ca. 11% of the species in our dataset, both within the genus and between Vriesea and other genera, which is commensurate with hybridization underlying the hyperdiversity of Vriesea, and potentially other genera in Tillandsioideae. While additional genomic research will be needed to further clarify the contribution of hybridization to the rapid diversification of Vriesea, our study provides an important first data point suggesting its importance to the evolution of tropical plant diversity.

Identification of anthocyanin and other flavonoids from the green-blue petals of Puya alpestris (Bromeliaceae) and a clarification of their coloration mechanism

To understand the unique green-blue color of Puya alpestris (Bromeliaceae) flowers, we investigated their constituent anthocyanin and related compounds. An anthocyanin, two undescribed flavonols, and two flavones were isolated and identified as delphinidin 3,3',5'-tri-O-β-glucopyranoside, myricetin 3-O-[α-rhamnopyranosyl-(1 → 6)-β-glucopyranoside]-3',5'-di-O-β-glucopyranoside, myricetin 3,3',5'-tri-O-β-glucopyranoside, luteolin 4'-O-glucoside, and apigenin 4'-O-glucoside. Furthermore, the presence of chlorophyll has also been revealed. P. alpestris petals show a gradient color appearance: Green-blue at the tip and blue at the base. This color difference between the tip and base was used to analyze the pigment components underlying the green-blue color expression. It was found that the petal tip contains the anthocyanin, flavonols, flavones, and chlorophyll in high quantities. Furthermore, the pH of petal juice was 6.2 and 5.6 at the tip and base, respectively. In vitro reconstruction revealed the blue color expression occurred via an intermolecular copigmentation between the anthocyanin and flavones, as well as yellow color expression, which was due to an increase in the absorption at 400-450 nm of the flavonols under the higher pH conditions. Furthermore, we found that the petal extract obtaining using 50% acetone containing chlorophyll showed the same absorption spectrum as that observed for the raw petal. These results indicate that the green-blue color of P. alpestris flowers is developed via an intermolecular co-pigmentation of the anthocyanin (delphinidin 3,3',5'-tri-O-β-glucopyranoside) with flavones, such as luteolin 4'-O-glucoside, the yellow color expression of flavonols, such as myricetin 3,3',5'-tri-O-glucoside under relatively high pH conditions in the cell sap, and the presence of chlorophyll.

Microsatellite markers for the endangered Puya raimondii in Peru

PREMISE

Microsatellite primers were developed for Puya raimondii (Bromeliaceae), an endangered species distributed in the Andean Mountains of Bolivia and Peru.

METHODS AND RESULTS

Genome skimming of P. raimondii, P. macrura, and P. hutchisonii resulted in the selection of 46 pairs of cross-species microsatellite markers. Of these, 12 microsatellite primer pairs produced clear and polymorphic bands in P. raimondii. These primer sets were then used for the detection of potential polymorphisms in 84 P. raimondii individuals collected from four populations in Peru. The number of alleles per locus ranged from one to six, and the observed and expected levels of heterozygosity ranged from 0.000 to 0.8929 and from 0.000 to 0.7662, respectively.

CONCLUSIONS

The microsatellite markers developed in this study will be useful for future population genetic analyses and breeding system studies in P. raimondii.

What Do Nectarivorous Bats Like? Nectar Composition in Bromeliaceae With Special Emphasis on Bat-Pollinated Species

Floral nectar is the most important reward for pollinators and an integral component of the pollination syndrome. Nectar research has mainly focused on sugars or amino acids, whereas more comprehensive studies on the nectar composition of closely related plant species with different pollination types are rather limited. Nectar composition as well as concentrations of sugars, amino acids, inorganic ions, and organic acids were analyzed for 147 species of Bromeliaceae. This plant family shows a high diversity in terms of floral morphology, flowering time, and predominant pollination types (trochilophilous, trochilophilous/entomophilous, psychophilous, sphingophilous, chiropterophilous). Based on the analyses, we examined the relationship between nectar traits and pollination type in this family. Nectar of all analyzed species contained high amounts of sugars with different proportions of glucose, fructose, and sucrose. The total concentrations of amino acids, inorganic cations, and anions, or organic acids were much lower. The analyses revealed that the sugar composition, the concentrations of inorganic cations and anions as well as the concentration of malate in nectar of bat-pollinated species differed significantly from nectar of species with other pollination types. Flowers of bat-pollinated species contained a higher volume of nectar, which results in a total of about 25-fold higher amounts of sugar in bat-pollinated species than in insect-pollinated species. This difference was even higher for amino acids, inorganic anions and cations, and organic acids (between 50 and 100-fold). In general, bat-pollinated plant species invest large amounts of organic and inorganic compounds for their pollinators. Furthermore, statistical analyses reveal that the characteristics of nectar in Bromeliaceae are more strongly determined by the pollinator type rather than by taxonomic groups or phylogenetic relations. However, a considerable part of the variance cannot be explained by either of the variables, which means that additional factors must be responsible for the differences in the nectar composition.

Concerted anatomical change associated with crassulacean acid metabolism in the Bromeliaceae

Crassulacean acid metabolism (CAM) is a celebrated example of convergent evolution in plant ecophysiology. However, many unanswered questions surround the relationships among CAM, anatomy and morphology during evolutionary transitions in photosynthetic pathway. An excellent group in which to explore these issues is the Bromeliaceae, a diverse monocot family from the Neotropics in which CAM has evolved multiple times. Progress in the resolution of phylogenetic relationships among the bromeliads is opening new and exciting opportunities to investigate how evolutionary changes in leaf structure has tracked, or perhaps preceded, photosynthetic innovation. This paper presents an analysis of variation in leaf anatomical parameters across 163C3 and CAM bromeliad species, demonstrating a clear divergence in the fundamental aspects of leaf structure in association with the photosynthetic pathway. Most strikingly, the mean volume of chlorenchyma cells of CAM species is 22 times higher than that of C3 species. In two bromeliad subfamilies (Pitcairnioideae and Tillandsioideae), independent transitions from C3 to CAM are associated with increased cell succulence, whereas evolutionary trends in tissue thickness and leaf air space content differ between CAM origins. Overall, leaf anatomy is clearly and strongly coupled with the photosynthetic pathway in the Bromeliaceae, where the independent origins of CAM have involved significant anatomical restructuring.

Geography, environment and organismal traits in the diversification of a major tropical herbaceous angiosperm radiation

The generation of plant diversity involves complex interactions between geography, environment and organismal traits. Many macroevolutionary processes and emergent patterns have been identified in different plant groups through the study of spatial data, but rarely in the context of a large radiation of tropical herbaceous angiosperms. A powerful system for testing interrelated biogeographical hypotheses is provided by the terrestrial bromeliads, a Neotropical group of extensive ecological diversity and importance. In this investigation, distributional data for 564 species of terrestrial bromeliads were used to estimate variation in the position and width of species-level hydrological habitat occupancy and test six core hypotheses linking geography, environment and organismal traits. Taxonomic groups and functional types differed in hydrological habitat occupancy, modulated by convergent and divergent trait evolution, and with contrasting interactions with precipitation abundance and seasonality. Plant traits in the Bromeliaceae are intimately associated with bioclimatic differentiation, which is in turn strongly associated with variation in geographical range size and species richness. These results emphasize the ecological relevance of structural-functional innovation in a major plant radiation.

Comparative Analysis of Four Buckwheat Species Based on Morphology and Complete Chloroplast Genome Sequences

Buckwheat is a nutritional and economically crop belonging to Polygonaceae, Fagopyrum. To better understand the mutation patterns and evolution trend in the chloroplast (cp) genome of buckwheat, and found sufficient number of variable regions to explore the phylogenetic relationships of this genus, two complete cp genomes of buckwheat including Fagopyrum dibotrys (F. dibotrys) and Fagopyrum luojishanense (F. luojishanense) were sequenced, and other two Fagopyrum cp genomes were used for comparative analysis. After morphological analysis, the main difference among these buckwheat were height, leaf shape, seeds and flower type. F. luojishanense was distinguishable from the cultivated species easily. Although the F. dibotrys and two cultivated species has some similarity, they different in habit and component contents. The cp genome of F. dibotrys was 159,320 bp while the F. luojishanense was 159,265 bp. 48 and 61 SSRs were found in F. dibotrys and F. luojishanense respectively. Meanwhile, 10 highly variable regions among these buckwheat species were located precisely. The phylogenetic relationships among four Fagopyrum species based on complete cp genomes was showed. The results suggested that F. dibotrys is more closely related to Fagopyrum tataricum. These data provided valuable genetic information for Fagopyrum species identification, taxonomy, phylogenetic study and molecular breeding.

Diversification of Bromelioideae (Bromeliaceae) in the Brazilian Atlantic rainforest: A case study in Aechmea subgenus Ortgiesia

Aechmea subgenus Ortgiesia comprises ca. 20 species distributed in Brazil, Argentina, Paraguay, and Uruguay, with a center of diversity in the Brazilian Atlantic rainforest. We examined interspecific relationships of Ortgiesia based on Amplified Fragment Length Polymorphisms (AFLP). Ninety-six accessions belonging to 14 species of Ortgiesia were sampled, and genotyped with 11 AFLP primer combinations. The neighbor joining (NJ) tree depicted two main genetic groups within Aechmea subgenus Ortgiesia, and four subgroups. The NJ tree showed short internal branches, indicating an overall shallow genetic divergence among Ortgiesia species as expected for the recently radiated subfamily Bromelioideae. Our results suggest that hybridization and/or incomplete lineage sorting may have hampered the reconstruction of interspecific relationships in Aechmea subgenus Ortgiesia. The mapping of petal color (yellow, blue, pink, or white), inflorescence type (simple or compound), and inflorescence shape (ellipsoid, subcylindric, cylindric, or pyramidal) against the NJ tree indicated that these characters are of limited taxonomic use in Aechmea subgenus Ortgiesia due to homoplasy. An analysis of the current distribution of Ortgiesia identified the southern region of the Brazilian Atlantic rainforest, between latitudes of 26° and 27°S, as the center of diversity for the subgenus.

Munroa argentina, a Grass of the South American Transition Zone, Survived the Andean Uplift, Aridification and Glaciations of the Quaternary

The South American Transition Zone (SATZ) is a biogeographic area in which not only orogeny (Andes uplift) and climate events (aridification) since the mid-Miocene, but also Quaternary glaciation cycles had an important impact on the evolutionary history of the local flora. To study this effect, we selected Munroa argentina, an annual grass distributed in the biogeographic provinces of Puna, Prepuna and Monte. We collected 152 individuals from 20 localities throughout the species' range, ran genetic and demographic analyses, and applied ecological niche modeling. Phylogenetic and population genetic analyses based on cpDNA and AFLP data identified three phylogroups that correspond to the previously identified subregions within the SATZ. Molecular dating suggests that M. argentina has inhabited the SATZ since approximately 3.4 (4.2-1.2) Ma and paleomodels predict suitable climate in these areas during the Interglacial period and the Last Glacial Maximum. We conclude that the current distribution of M. argentina resulted from the fragmentation of its once continuous range and that climate oscillations promoted ecological differences that favored isolation by creating habitat discontinuity.

The temporal build-up of hummingbird/plant mutualisms in North America and temperate South America

Background

The 361 species of hummingbirds that occur from Alaska to Patagonia pollinate ~7,000 plant species with flowers morphologically adapted to them. To better understand this asymmetric diversity build-up, this study analyzes the origin of hummingbird/plant mutualisms in North America and temperate South America, based on new compilations of the 184 hummingbird-adapted species in North America, the 56 in temperate South America, and complete species-level phylogenies for the relevant hummingbirds in both regions, namely five in temperate South America and eight in North America. Because both floras are relatively well sampled phylogenetically, crown or stem ages of many representative clades could be inferred. The hummingbird chronogram was calibrated once with fossils, once with substitutions rates, while plant chronograms were taken from the literature or in 13 cases newly generated.

Results

The 184 North American hummingbird-adapted species belong to ca. 70 lineages for 19 of which (comprising 54 species) we inferred divergence times. The 56 temperate South American hummingbird-adapted species belong to ca. 35 lineages, for 17 of which (comprising 25 species) we inferred divergence times. The oldest hummingbirds and hummingbird-adapted plant lineages in the South American assemblage date to 16–17 my, those in the North American assemblage to 6–7 my. Few hummingbird-pollinated clades in either system have >4 species.

Conclusions

The asymmetric diversity build-up between hummingbirds and the plants dependent on them appears to arise not from rapid speciation within hummingbird-pollinated clades, but instead from a gradual and continuing process in which independent plant species switch from insect to bird pollination. Diversification within hummingbird-pollinated clades in the temperate regions of the Americas appears mainly due to habitat specialization and allopatric speciation, not bird pollination per se. Interaction tanglegrams, even if incomplete, indicate a lack of tight coevolution as perhaps expected for temperate-region mutualisms involving nectar-feeding vertebrates.

Electronic supplementary material

The online version of this article (doi:10.1186/s12862-015-0388-z) contains supplementary material, which is available to authorized users.

Latitudinal environmental niches and riverine barriers shaped the phylogeography of the Central Chilean endemic Dioscorea humilis (Dioscoreaceae)

The effects of Pleistocene glaciations and geographical barriers on the phylogeographic patterns of lowland plant species in Mediterranean-climate areas of Central Chile are poorly understood. We used Dioscorea humilis (Dioscoreaceae), a dioecious geophyte extending 530 km from the Valparaíso to the Bío-Bío Regions, as a case study to disentangle the spatio-temporal evolution of populations in conjunction with latitudinal environmental changes since the Last Inter-Glacial (LIG) to the present. We used nuclear microsatellite loci, chloroplast (cpDNA) sequences and environmental niche modelling (ENM) to construct current and past scenarios from bioclimatic and geographical variables and to infer the evolutionary history of the taxa. We found strong genetic differentiation at nuclear microsatellite loci between the two subspecies of D. humilis, probably predating the LIG. Bayesian analyses of population structure revealed strong genetic differentiation of the widespread D. humilis subsp. humilis into northern and southern population groups, separated by the Maipo river. ENM revealed that the ecological niche differentiation of both groups have been maintained up to present times although their respective geographical distributions apparently fluctuated in concert with the climatic oscillations of the Last Glacial Maximum (LGM) and the Holocene. Genetic data revealed signatures of eastern and western postglacial expansion of the northern populations from the central Chilean depression, whereas the southern ones experienced a rapid southward expansion after the LGM. This study describes the complex evolutionary histories of lowland Mediterranean Chilean plants mediated by the summed effects of spatial isolation caused by riverine geographical barriers and the climatic changes of the Quaternary.

Systematics, biogeography, and character evolution of Sparganium (Typhaceae): diversification of a widespread, aquatic lineage

PREMISE OF THE STUDY

Sparganium (Typhaceae) is a genus of aquatic monocots containing ±14 species, with flowers aggregated in unisexual, spherical heads, and habit ranging from floating to emergent. Sparganium presents an opportunity to investigate diversification, character evolution, and biogeographical relationships in a widespread temperate genus of aquatic monocots. We present a fossil-calibrated, molecular phylogeny of Sparganium based on analysis of two chloroplast and two nuclear markers. Within this framework, we examine character evolution in both habit and stigma number and infer the ancestral area and biogeographic history of the genus. •

METHODS

Sequence data from two cpDNA and two nDNA markers were analyzed using maximum parsimony, maximum likelihood, and Bayesian inference. We used the program BEAST to simultaneously estimate phylogeny and divergence times, S-DIVA and Lagrange for biogeographical reconstruction, and BayesTraits to examine locule number and habit evolution. •

KEY RESULTS

Two major clades were recovered with strong support: one composed of S. erectum and S. eurycarpum; and the other containing all remaining Sparganium. We realigned the subgenera to conform to these clades. Divergence time analysis suggests a Miocene crown origin but Pliocene diversification. Importantly, the floating-leaved habit has arisen multiple times in the genus, from emergent ancestors-contrary to past hypotheses. •

CONCLUSIONS

Cooling trends during the Tertiary are correlated with the isolation of temperate Eurasian and North American taxa. Vicariance, long-distance dispersal, and habitat specialization are proposed as mechanisms for Sparganium diversification.

Progenitor-derivative speciation in Pozoa (Apiaceae, Azorelloideae) of the southern Andes

BACKGROUND AND AIMS

Studies examining patterns and processes of speciation in South America are fewer than in North America and Europe. One of the least well documented processes has been progenitor-derivative speciation. A particularly instructive example occurs in the southern Andes in the genus Pozoa (Apiaceae, Azorelloideae), which consists of only two diploid outcrossing species, the widespread P. coriacea and the geographically and ecologically restricted P. volcanica. This paper tests the hypothesis that the latter species originated from the former through local geographical and ecological isolation by progenitor-derivative speciation.

METHODS

DNA sequences were analysed from Pozoa and the related South American genera Asteriscium, Eremocharis and Gymnophyton from non-coding regions of the plastid genome, ndhF-rpl32 and rpl32-trnL, plus incorporation of previously reported rpl16 intron and trnD-trnT intergenic spacer sequences. Amplified fragment length polymorphism (AFLP) data from 105 individuals in 21 populations throughout the entire range of distribution of the genus were used for estimation of genetic diversity, divergence and SplitsTree network analysis. Ecological factors, including habitat and associated species, were also examined.

KEY RESULTS

Pozoa coriacea is more similar genetically to the outgroup genera, Asteriscium and Eremocharis, than is P. volcanica. At the population level, only P. volcanica is monophyletic, whereas P. coriacea is paraphyletic. Analyses of genetic differentiation among populations and genetic divergence and diversity of the species show highest values in P. coriacea and clear reductions in P. volcanica. Pozoa coriacea occurs in several types of high elevation habitats, whereas P. volcanica is found only in newly formed open volcanic ash zones.

CONCLUSIONS

All facts support that Pozoa represents a good example of progenitor-derivative speciation in the Andes of southern South America.

Phylogeny, adaptive radiation, and historical biogeography in Bromeliaceae: insights from an eight-locus plastid phylogeny

PREMISE

Bromeliaceae form a large, ecologically diverse family of angiosperms native to the New World. We use a bromeliad phylogeny based on eight plastid regions to analyze relationships within the family, test a new, eight-subfamily classification, infer the chronology of bromeliad evolution and invasion of different regions, and provide the basis for future analyses of trait evolution and rates of diversification.

METHODS

We employed maximum-parsimony, maximum-likelihood, and Bayesian approaches to analyze 9341 aligned bases for four outgroups and 90 bromeliad species representing 46 of 58 described genera. We calibrate the resulting phylogeny against time using penalized likelihood applied to a monocot-wide tree based on plastid ndhF sequences and use it to analyze patterns of geographic spread using parsimony, Bayesian inference, and the program S-DIVA.

RESULTS

Bromeliad subfamilies are related to each other as follows: (Brocchinioideae, (Lindmanioideae, (Tillandsioideae, (Hechtioideae, (Navioideae, (Pitcairnioideae, (Puyoideae, Bromelioideae))))))). Bromeliads arose in the Guayana Shield ca. 100 million years ago (Ma), spread centrifugally in the New World beginning ca. 16-13 Ma, and dispersed to West Africa ca. 9.3 Ma. Modern lineages began to diverge from each other roughly 19 Ma.

CONCLUSIONS

Nearly two-thirds of extant bromeliads belong to two large radiations: the core tillandsioids, originating in the Andes ca. 14.2 Ma, and the Brazilian Shield bromelioids, originating in the Serro do Mar and adjacent regions ca. 9.1 Ma.