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Pollinators are important drivers of angiosperm diversification at both micro- and macroevolutionary scales. Both hummingbirds and bats pollinate the species-rich and morphologically diverse genus Vriesea across its distribution in the Brazilian Atlantic Forest. Here, we (i) determine if floral traits predict functional groups of pollinators as documented, confirming the pollination syndromes in Vriesea and (ii) test if genetic structure in Vriesea is driven by geography (latitudinal and altitudinal heterogeneity) or ecology (pollination syndromes). We analysed 11 floral traits of 58 Vriesea species and performed a literature survey of Vriesea pollination biology. The genealogy of haplotypes was inferred and phylogenetic analyses were performed using chloroplast (rps16-trnk and matK) and nuclear (PHYC) molecular markers. Floral traits accurately predict functional groups of pollinators in Vriesea. Genetic groupings match the different pollination syndromes. Species with intermediate position were found between the groups, which share haplotypes and differ morphologically from the typical hummingbird- and bat-pollinated flowers of Vriesea. The phylogeny revealed moderately to well-supported clades which may be interpreted as species complexes. Our results suggest a role of pollinators driving ecological isolation in Vriesea clades. Incipient speciation and incomplete lineage sorting may explain the overall low genetic divergence within and among morphologically defined species, precluding the identification of clear species boundaries. The intermediate species with mixed floral types likely represent a window into shifts between pollinator syndromes. This study reports the morphological-genetic continuum that may be typical of ongoing pollinator-driven speciation in biodiversity hotspots.

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Leaf and stripe rust are major threats to wheat production worldwide. The effective, multiple rust resistances present in the Brazilian cultivar Toropi makes it an excellent choice for a genetic study of rust resistance. Testing of DNA from different seed lots of Toropi with 2,194 polymorphic 90K iSelect single nucleotide polymorphism markers identified significant genetic divergence, with as much as 35% dissimilarity between seed lots. As a result, further work was conducted with a single plant line derived from Toropi variant Toropi-6.4. A double haploid population with 168 lines derived from the cross Toropi-6.4 × Thatcher was phenotyped over multiple years and locations in Canada, New Zealand, and Kenya, with a total of seven field trials undertaken for leaf rust and nine for stripe rust. Genotyping with the 90K iSelect array, simple sequence repeat and Kompetitive allele-specific polymerase chain reaction markers resulted in a genetic map of 3,043 cM, containing 1,208 nonredundant markers. Significant quantitative trait loci (QTL) derived from Toropi-6.4 were identified in multiple environments on chromosomes 1B (QLr.crc-1BL/QYr.crc-1BL), 3B (QLr.crc-3BS), 4B (QYr.crc-4BL), 5A (QLr.crc-5AL and QYr.crc-5AL), and 5D (QLr.crc-5DS). The QTL QLr.crc-1BL/QYr.crc-1BL colocated with the multi-rust resistance locus Lr46/Yr29, while the QTL QLr.crc-5DS located to the Lr78 locus previously found in a wheat backcross population derived from Toropi. Comparisons of QTL combinations showed QLr.crc-1BL to contribute a significantly enhanced leaf rust resistance when combined with QLr.crc-5AL or QLr.crc-5DS, more so than when QLr.crc-5AL and QLr.crc-5DS were combined. A strong additive effect was also seen when the stripe rust resistance QTL QYr.crc-1BL and QYr.crc-5AL were combined.

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PREMISE: Despite the efforts to understand the processes that shape neotropical biodiversity, the complexity of certain biomes, such as the Atlantic Forest (AF), prevents the generalization of patterns. Initially, ecological niche modeling (ENM), with phylogeographic studies, identified past stable areas in the central and northern portions of the AF, while the southern portion was thought to be highly fragmented. Here, we examined the phylogeography, historical patterns, genetic diversity, and population structure of Vriesea incurvata, an endemic species of the southern portion of the AF. METHODS: We evaluated 149 individuals using two plastid DNA regions (cpDNA) and 13 nuclear microsatellite markers (nuSSRs) to access the historical patterns, genetic diversity, and structure of V. incurvata populations. We also conducted historical demography and ENM analyses. RESULTS: We found moderate to high genetic diversity and low population structure for both genomes. The cpDNA network revealed high haplotype sharing. The ENM suggested no drastic changes in suitable areas for V. incurvata occurrence, corroborating the finding of no phylogeographic structure. CONCLUSIONS: Contrary to some studies, our results indicate that the southern AF was a historically stable climate region for V. incurvata occupation after southward colonization by the species. Past climatic changes probably did not cause structuring among its populations.

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The Southern Brazilian Highlands are composed by a mosaic of Mixed Ombrophilous Forest (MOF) and grassland formations, an interesting landscape for the study of population structure. We analyzed the genetic diversity within and among populations of the MOF-endemic bromeliad Vriesea reitzii by genotyping seven nuclear microsatellite loci in 187 individuals from six populations. We characterized levels of genetic diversity and assessed the genetic structure among populations. Vriesea reitzii populations showed high levels of genetic variation (number of alleles 28 - 43, allelic richness 3.589 - 5.531) and moderate levels of genetic differentiation (FST = 0.123, RST = 0.096). The high levels of genetic diversity may be explained by species life-history traits, such as habit and mating system. The moderate structure may be a product of the combination of ancient and contemporary gene flow, resulting from the expansion of the forest in the Holocene, and/or due to facilitated dispersal mediated by the MOF's mosaic landscape. The genetic results indicated no imminent threat to this bromeliad. However, the species is highly associated with the MOF, putting landscape conservation at the center of conservation efforts for the species' maintenance.

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Abstract The Southern Brazilian Highlands are composed by a mosaic of Mixed Ombrophilous Forest (MOF) and grassland formations, an interesting landscape for the study of population structure. We analyzed the genetic diversity within and among populations of the MOF-endemic bromeliad Vriesea reitzii by genotyping seven nuclear microsatellite loci in 187 individuals from six populations. We characterized levels of genetic diversity and assessed the genetic structure among populations. Vriesea reitzii populations showed high levels of genetic variation (number of alleles 28 - 43, allelic richness 3.589 - 5.531) and moderate levels of genetic differentiation (FST = 0.123, RST = 0.096). The high levels of genetic diversity may be explained by species life-history traits, such as habit and mating system. The moderate structure may be a product of the combination of ancient and contemporary gene flow, resulting from the expansion of the forest in the Holocene, and/or due to facilitated dispersal mediated by the MOF's mosaic landscape. The genetic results indicated no imminent threat to this bromeliad. However, the species is highly associated with the MOF, putting landscape conservation at the center of conservation efforts for the species' maintenance.

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PREMISE OF THE STUDY: The yellow-flowered Aechmea subgenus Ortgiesia (yfAsO) (Bromeliaceae) is a group of seven morphologically similar bromeliads found mostly in the southern Brazilian Atlantic rainforest. The recent origin of this group probably contributes to its taxonomic complexity. The aims of this study were to investigate the levels of genetic diversity and structure at the population and species levels, to gain insight into the processes behind the diversification of the group, and to contribute to the establishment of species boundaries. METHODS: We sequenced two noncoding regions of the chloroplast genome (rpl32-trnL and rps16-trnK) and the nuclear phyC gene in 204 and 153 individuals, respectively, representing the seven species of the group. Phylogeographical and population genetics approaches were used. KEY RESULTS: Three of the seven yfAsO showed some degree of genetic differentiation among species. Divergence time for the group was dated to around 4 million years ago. Areas of conservation value were identified, and a scenario of multiple refugia in the southern Brazilian Atlantic rainforest during the Pleistocene climatic oscillations is suggested. CONCLUSIONS: We hypothesized that incomplete lineage sorting and localized hybridization events are responsible for the low levels of genetic differentiation and the taxonomic complexity observed among and within the seven yfAsO species. Further studies on Aechmea comata and Aechmea kertesziae will be necessary to clarify the boundary between these two species. Most of the populations sampled showed high genetic diversity and/or unique haplotypes; they should be prioritized for conservation purposes.

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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.

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Bromeliaceae is a morphologically distinctive and ecologically diverse family originating in the New World. Three centers of diversity, 58 genera, and about 3,140 bromeliad species are currently recognized. We compiled all of the studies related to the reproductive biology, genetic diversity, and population structure of the Bromeliaceae, and discuss the evolution and conservation of this family. Bromeliads are preferentially pollinated by vertebrates and show marked variation in breeding systems, from predominant inbreeding to predominant outcrossing, as well as constancy in chromosome number (2n = 2x = 50). Autogamous or mixed mating system bromeliads have a high inbreeding coefficient (F(IS)), while outcrossing species show low F(IS). The degree of differentiation among populations (F(ST))of species ranges from 0.043 to 0.961, which can be influenced by pollen and seed dispersal effects, clonal growth, gene flow rates, and connectivity among populations. The evolutionary history of the Bromeliaceae is poorly known, although some studies have indicated that the family arose in the Guayana Shield roughly 100 Mya. We believe that genetic, cytogenetic, and reproductive data will be essential for diagnosing species status and for assisting conservation programs.

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Microsatellite markers were isolated in Dyckia distachya, an endangered bromeliad from southern Brazil, which will be useful to assess the population genetic structure and reproductive success in introduced and natural populations of this species. Twenty microsatellite loci were developed from an enriched genomic library, and nine of these were amplified. The loci were characterized in 43 individuals from introduced and wild D. distachya populations. All nine loci were polymorphic, with four to ten alleles per locus. In an introduced population the observed and expected heterozygosities ranged from 0.136-0.667 and 0.543-0.877, respectively, while in a wild population it ranged from 0.000 to 0.895 and from 0.050 to 0.811, respectively. The development of these microsatellite markers will contribute to investigations of the reproductive potential and viability of introduced populations of D. distachya as well as the single known wild population. Cross-amplification in other Bromeliaceae species was successful, with high rates in four loci, demonstrating the applicability of these microsatellite markers in other taxa.

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