Novas ocorrências e distribuição do gênero Passiflora L. no Rio Grande do Sul, Brasil

The Passiflora L. genus is the most diversified of the Passifloraceae family, with at least 525 species. Up to now 140 species were identified in Brazil, of which 17 were previously reported as occurring in Rio Grande do Sul state (RS). With the objective of sampling these species several regions of the State were investigated through field work, species identification being performed by morphological analyses. Samples from 18 putative species were obtained in several regions of RS, and P. urnaefolia Rusby and P. urubiciensis Cervi were recorded for the first time in the State, while P. tricuspis Mast., described as occurring in the region, was not found. The results indicated that new collections should be made to found other species of Passiflora in RS.O gênero Passiflora L. é o mais diversificado da família Passifloraceae, com pelo menos 525 espécies. Até agora já foram identificadas 140 espécies para o Brasil, sendo que foram 17 espécies previamente registradas como ocorrendo no Rio Grande do Sul (RS). Objetivando amostrar essas espécies, foram investigadas diversas regiões do Estado através de saídas a campo, sendo a identificação das espécies feita através de análises morfológicas. Foram coletadas amostras de 18 espécies putativas em diversas regiões do RS, sendo que P. urnaefolia Rusby e P. urubiciensis Cervi tiveram sua ocorrência observada pela primeira vez para o Estado, e P. tricuspis Mast., descrita na literatura como ocorrendo na região, não foi encontrada. Os resultados indicaram que novas coletas devem ser feitas com a finalidade de melhor conhecer a distribuição de Passiflora no RS e até mesmo encontrar outras espécies

The use and limits of ITS data in the analysis of intraspecific variation in Passiflora L. (Passifloraceae)

The discovery and characterization of informative intraspecific genetic markers is fundamental for evolutionary and conservation genetics studies. Here, we used nuclear ribosomal ITS sequences to access intraspecific genetic diversity in 23 species of the genus Passiflora L. Some degree of variation was detected in 21 of these. The Passiflora and Decaloba (DC.) Rchb. subgenera showed significant differences in the sizes of the two ITS regions and in GC content, which can be related to reproductive characteristics of species in these subgenera. Furthermore, clear geographical patterns in the spatial distribution of sequence types were identified in six species. The results indicate that ITS may be a useful tool for the evaluation of intraspecific genetic variation in Passiflora

Efficiency of ITS Sequences for DNA Barcoding in Passiflora (Passifloraceae)

DNA barcoding is a technique for discriminating and identifying species using short, variable, and standardized DNA regions. Here, we tested for the first time the performance of plastid and nuclear regions as DNA barcodes in Passiflora. This genus is a largely variable, with more than 900 species of high ecological, commercial, and ornamental importance. We analyzed 1034 accessions of 222 species representing the four subgenera of Passiflora and evaluated the effectiveness of five plastid regions and three nuclear datasets currently employed as DNA barcodes in plants using barcoding gap, applied similarity-, and tree-based methods. The plastid regions were able to identify less than 45% of species, whereas the nuclear datasets were efficient for more than 50% using “best match” and “best close match” methods of TaxonDNA software. All subgenera presented higher interspecific pairwise distances and did not fully overlap with the intraspecific distance, and similarity-based methods showed better results than tree-based methods. The nuclear ribosomal internal transcribed spacer 1 (ITS1) region presented a higher discrimination power than the other datasets and also showed other desirable characteristics as a DNA barcode for this genus. Therefore, we suggest that this region should be used as a starting point to identify Passiflora species

Genetic diversity in Calibrachoa pygmaea (Solanaceae): A hawkmoth-pollinated nightshade from the Pampas

ABSTRACT Calibrachoa pygmaea is a unique species of Calibrachoa, especially concerning its flower morphology and the environment where it occurs. The species is self-incompatible and is narrowly distributed in wet and flooded fields of the Pampas region. We characterize the genetic diversity of the species based on traditional plastid markers and newly developed nuclear microsatellites to identify drivers that guide its evolution. Our results identified markers that are informative and useful for studying the population structure of C. pygmaea, as well as that of other species of Calibrachoa. Both marker sets were congruent in developing conclusions regarding the evolutionary scenario of C. pygmaea, and revealed that the genetic variability and population structure of the species could be explained by common allele fixation or shared ancestral polymorphism, while its diversification can be attributed mainly to the species’ dispersal ability and certain ecological features

Genetic diversity and population structure of naturally rare Calibrachoa species with small distribution in southern Brazil

Abstract Calibrachoa is a South-American genus comprising 27 species, several considered endemic or rare; few were subjects in genetic studies. We attempted to generate new data about the phylogenetically related and rare species C. eglandulata, C. sendtneriana, C. serrulata, and C. spathulata concerning their genetic diversity and population structure, which, coupled with their known restricted distribution, could help access their conservation status and contribute to the study of the Brazilian biodiversity. We sequenced 88 individuals for plastid intergenic spacers and genotyped 186 individuals for five microsatellite loci. Compared among each other, C. sendtneriana and C. serrulata presented the highest values of genetic diversity [π% (sd) = 0.23 (0.14) and 0.43 (0.25), respectively], followed by C. spathulata [π% (sd) = 0.19 (0.12)] and C. eglandulata [π% (sd) = 0.02 (0.03)]. Population differentiation was evident for these latter species, whereas it was not significant for C. sendtneriana and C. serrulata. Factors such as habitat specificity and fragmentation, pollination syndrome, and life history could explain the observed patterns. Based on the new genetic data and the species’ biology, a conservation status was assigned for C. sendtneriana and the status of the other three species was reviewed

Data from: Geological and climatic changes in quaternary shaped the evolutionary history of Calibrachoa heterophylla, an endemic South-Atlantic species of petunia

Background: The glacial and interglacial cycles that characterized the Quaternary greatly affected the distribution and genetic diversity of plants. In the Neotropics, few phylogeographic studies have focused on coastal species outside of the Atlantic Rainforest. Climatic and sea level changes during the Quaternary played an important role in the evolutionary history of many organisms found in coastal regions. To contribute to a better understanding of plant evolution in this environment in Southern South America, we focused on Calibrachoa heterophylla (Solanaceae), an endemic and vulnerable wild petunia species from the South Atlantic Coastal Plain (SACP). Results: We assessed DNA sequences from two cpDNA intergenic spacers and analyzed them using a phylogeographic approach. The present phylogeographic study reveals the influence of complex geologic and climatic events on patterns of genetic diversification. The results indicate that C. heterophylla originated inland and subsequently colonized the SACP; the data show that the inland haplogroup is more ancient than the coastal one and that the inland was not affected by sea level changes in the Quaternary. The major diversification of C. heterophylla that occurred after 0.4 Myr was linked to sea level oscillations in the Quaternary, and any diversification that occurred before this time was obscured by marine transgressions that occurred before the coastal sand barrier’s formation. Results of the Bayesian skyline plot showed a recent population expansion detected in C. heterophylla seems to be related to an increase in temperature and humidity that occurred at the beginning of the Holocene. Conclusions: The geographic clades have been formed when the coastal plain was deeply dissected by paleochannels and these correlate very well with the distributional limits of the clades. The four major sea transgressions formed a series of four sand barriers parallel to the coast that progressively increased the availability of coastal areas after the regressions and that may have promoted the geographic structuring of genetic diversity observed today. The recent population expansion for the entire species may be linked with the event of marine regression after the most recent sea transgression at ~5 kya

Alignment

trnH-psbA - trnS-trnG alignment [trnh-psba:1-457pb; trns-trng:458-1243pb

Secondary structure of nrDNA Internal Transcribed Spacers as a useful tool to align highly divergent species in phylogenetic studies

Abstract Recently, it has been suggested that internal transcribed spacer (ITS) sequences are under selective constraints to preserve their secondary structure. Here, we investigate the patterns of the ITS nucleotide and secondary structure conservation across the Passiflora L. genus to evaluate the potential use of secondary structure data as a helpful tool for the alignment in taxonomically complex genera. Considering the frequent use of ITS, this study also presents a perspective on future analyses in other plant groups. The ITS1 and ITS2 sequences presented significant differences for mean values of the lowest energy state (LES) and for number of hairpins in different Passiflora subgenera. Statistical analyses for the subgenera separately support significant differences between the LES values and the total number of secondary structures for ITS. In order to evaluate whether the LES values of ITS secondary structures were related to selective constraints, we compared these results among 120 ITS sequences from Passiflora species and 120 randomly generated sequences. These analyses indicated that Passiflora ITS sequences present characteristics of a region under selective constraint to maintain the secondary structure showing to be a promising tool to improve the alignments and identify sites with non-neutral substitutions or those correlated evolutionary steps