Flora of the Usina São José, Igarassu, Pernambuco State, Brazil: Asteraceae / Flora da Usina São José, Igarassu, Estado de Pernambuco, Brasil: Asteraceae

Asteraceae is one of the largest families among angiosperms, concentrated mainly in open vegetation. This study aims to survey the floristic inventory of Asteraceae in fragments of Atlantic Forest of Usina São José (USJ), Igarassu, Pernambuco State, providing subsidies for an updated taxonomic recognition of species in the region. In total, 32 species from 27 genera and 10 tribes were identifield. The tribes with the greatest number of species are Eupatorieae (8 spp.), Vernonieae (7 spp.) and Heliantheae (6 spp.). The most representative genera were Mikania (3 spp.), Acanthospermum, Elephantopus and Emilia (2 spp. each). Gamochaeta pensylvanica presents here the first occurrence for the State of Pernambuco. Identification key is presented, followed by taxonomic comments and geographic distribution for each taxon, and illustrations are presented.

Asteraceae é uma das maiores famílias dentre as angiospermas, concentrada principalmente em vegetações abertas. O presente trabalho tem como objetivo realizar um inventário florístico de Asteraceae em fragmentos de Mata Atlântica da Usina São José (USJ), Igarassu, Pernambuco, oferecendo subsídios para o reconhecimento das espécies na região.  Foram amostradas 32 espécies circunscritas a 27 gêneros e 10 tribos. As tribos com maior número de espécies são Eupatorieae (8 spp.), Vernonieae (7 spp.) e Heliantheae (6 spp.). Os gêneros mais representativos são Mikania (3 spp.), Acanthospermum, Elephantopus e Emilia (2 spp. cada). Gamochaeta pensylvanica apresenta aqui a primeira ocorrência para o Estado de Pernambuco. São fornecidas chave de identificação, descrições, ilustrações, comentários taxonômicos e de distribuição geográfica para cada espécie.

Comparative analyses of Mikania (Asteraceae: Eupatorieae) plastomes and impact of data partitioning and inference methods on phylogenetic relationships.

We assembled new plastomes of 19 species of Mikania and of Ageratina fastigiata, Litothamnus nitidus, and Stevia collina, all belonging to tribe Eupatorieae (Asteraceae). We analyzed the structure and content of the assembled plastomes and used the newly generated sequences to infer phylogenetic relationships and study the effects of different data partitions and inference methods on the topologies. Most phylogenetic studies with plastomes ignore that processes like recombination and biparental inheritance can occur in this organelle, using the whole genome as a single locus. Our study sought to compare this approach with multispecies coalescent methods that assume that different parts of the genome evolve at different rates. We found that the overall gene content, structure, and orientation are very conserved in all plastomes of the studied species. As observed in other Asteraceae, the 22 plastomes assembled here contain two nested inversions in the LSC region. The plastomes show similar length and the same gene content. The two most variable regions within Mikania are rpl32-ndhF and rpl16-rps3, while the three genes with the highest percentage of variable sites are ycf1, rpoA, and psbT. We generated six phylogenetic trees using concatenated maximum likelihood and multispecies coalescent methods and three data partitions: coding and non-coding sequences and both combined. All trees strongly support that the sampled Mikania species form a monophyletic group, which is further subdivided into three clades. The internal relationships within each clade are sensitive to the data partitioning and inference methods employed. The trees resulting from concatenated analysis are more similar among each other than to the correspondent tree generated with the same data partition but a different method. The multispecies coalescent analysis indicate a high level of incongruence between species and gene trees. The lack of resolution and congruence among trees can be explained by the sparse sampling (~ 0.45% of the currently accepted species) and by the low number of informative characters present in the sequences. Our study sheds light into the impact of data partitioning and methods over phylogenetic resolution and brings relevant information for the study of Mikania diversity and evolution, as well as for the Asteraceae family as a whole.

Asteraceae in the Curimataú Ocidental microregion, Paraíba State, Brazil / Asteraceae na microrregião do Curimataú Ocidental, Estado da Paraíba, Brasil

Caatinga formations comprise the most important vegetation mosaic of the northeastern region. Asteraceae constitutes one of the five richest species families for this area, however, constantly neglected in floristic and taxonomic studies. The aim of this paper was to conduct a floristic survey of this group in the Curimataú Ocidental microregion, Paraíba State, which is considered an area with few information about its biodiversity, especially the flora. We based this study on monthly collections from April/2018 to September/2019 in the most diverse places of the area and consulting collections of the main herbaria of Paraíba and Pernambuco States. We recorded 36 genera and 38 species. Identification keys, descriptions, illustrations and images are presented for the sampled taxa.

As formações de caatinga compreendem o mais importante mosaico vegetacional da região Nordeste. Asteraceae constitui uma das cinco famílias mais ricas em número de espécies para essas áreas, no entanto é constantemente negligenciada em estudos florísticos e taxonômicos. O objetivo deste trabalho foi realizar o levantamento florístico desse grupo na microrregião do Curimataú Ocidental, Estado da Paraíba, considerada uma área com poucas informações acerca da sua biodiversidade, em especial da flora. Baseamos este estudo em coletas mensais entre abril/2018 a setembro/2019 nos mais diversos pontos da área e na consulta às coleções dos principais Herbários dos Estados da Paraíba e de Pernambuco. Registramos 36 gêneros e 38 espécies. São apresentadas chaves de identificação, descrições, ilustrações e imagens para os taxóns amostrados.

Extremely low nucleotide diversity among thirty-six new chloroplast genome sequences from Aldama (Heliantheae, Asteraceae) and comparative chloroplast genomics analyses with closely related genera.

Aldama (Heliantheae, Asteraceae) is a diverse genus in the sunflower family. To date, nearly 200 Asteraceae chloroplast genomes have been sequenced, but the plastomes of Aldama remain undescribed. Plastomes in Asteraceae usually show little sequence divergence, consequently, our hypothesis is that species of Aldama will be overall conserved. In this study, we newly sequenced 36 plastomes of Aldama and of five species belonging to other Heliantheae genera selected as outgroups (i.e., Dimerostemma asperatum, Helianthus tuberosus, Iostephane heterophylla, Pappobolus lanatus var. lanatus, and Tithonia diversifolia). We analyzed the structure and gene content of the assembled plastomes and performed comparative analyses within Aldama and with other closely related genera. As expected, Aldama plastomes are very conserved, with the overall gene content and orientation being similar in all studied species. The length of the plastome is also consistent and the junction between regions usually contain the same genes and have similar lengths. A large ∼20 kb and a small ∼3 kb inversion were detected in the Large Single Copy (LSC) regions of all assembled plastomes, similarly to other Asteraceae species. The nucleotide diversity is very low, with only 1,509 variable sites in 127,466 bp (i.e., 1.18% of the sites in the alignment of 36 Aldama plastomes, with one of the IRs removed, is variable). Only one gene, rbcL, shows signatures of positive selection. The plastomes of the selected outgroups feature a similar gene content and structure compared to Aldama and also present the two inversions in the LSC region. Deletions of different lengths were observed in the gene ycf2. Multiple SSRs were identified for the sequenced Aldama and outgroups. The phylogenetic analysis shows that Aldama is not monophyletic due to the position of the Mexican species A. dentata. All Brazilian species form a strongly supported clade. Our results bring new understandings into the evolution and diversity of plastomes at the species level.

Phylogenomics Yields New Insight Into Relationships Within Vernonieae (Asteraceae).

Asteraceae, or the sunflower family, is the largest family of flowering plants and is usually considered difficult to work with, not only due to its size, but also because of the abundant cases of polyploidy and ancient whole-genome duplications. Traditional molecular systematics studies were often impaired by the low levels of variation found in chloroplast markers and the high paralogy of traditional nuclear markers like ITS. Next-generation sequencing and novel phylogenomics methods, such as target capture and Hyb-Seq, have provided new ways of studying the phylogeny of the family with great success. While the resolution of the backbone of the family is in progress with some results already published, smaller studies focusing on internal clades of the phylogeny are important to increase sampling and allow morphological, biogeography, and diversification analyses, as well as serving as basis to test the current infrafamilial classification. Vernonieae is one of the largest tribes in the family, accounting for approximately 1,500 species. From the 1970s to the 1990s, the tribe went through several reappraisals, mainly due to the splitting of the mega genus Vernonia into several smaller segregates. Only three phylogenetic studies focusing on the Vernonieae have been published to date, both using a few molecular markers, overall presenting low resolution and support in deepest nodes, and presenting conflicting topologies when compared. In this study, we present the first attempt at studying the phylogeny of Vernonieae using phylogenomics. Even though our sampling includes only around 4% of the diversity of the tribe, we achieved complete resolution of the phylogeny with high support recovering approximately 700 nuclear markers obtained through target capture. We also analyzed the effect of missing data using two different matrices with different number of markers and the difference between concatenated and gene tree analysis.

Comprehensive untargeted metabolomics of Lychnnophorinae subtribe (Asteraceae: Vernonieae) in a phylogenetic context.

Members of the subtribe Lychnophorinae occur mostly within the Cerrado domain of the Brazilian Central Plateau. The relationships between its 11 genera, as well as between Lychnophorinae and other subtribes belonging to the tribe Vernonieae, have recently been investigated upon a phylogeny based on molecular and morphological data. We report the use of a comprehensive untargeted metabolomics approach, combining HPLC-MS and GC-MS data, followed by multivariate analyses aiming to assess the congruence between metabolomics data and the phylogenetic hypothesis, as well as its potential as a chemotaxonomic tool. We analyzed 78 species by UHPLC-MS and GC-MS in both positive and negative ionization modes. The metabolic profiles obtained for these species were treated in MetAlign and in MSClust and the matrices generated were used in SIMCA for hierarchical cluster analyses, principal component analyses and orthogonal partial least square discriminant analysis. The results showed that metabolomic analyses are mostly congruent with the phylogenetic hypothesis especially at lower taxonomic levels (Lychnophora or Eremanthus). Our results confirm that data generated using metabolomics provide evidence for chemotaxonomical studies, especially for phylogenetic inference of the Lychnophorinae subtribe and insight into the evolution of the secondary metabolites of this group.