RESUMO

The plastid genome of flowering plants generally shows conserved structural organization, gene arrangement, and gene content. While structural reorganizations are uncommon, examples have been documented in the literature during the past years. Here we assembled the entire plastome of Bignonia magnifica and compared its structure and gene content with nine other Lamiid plastomes. The plastome of B. magnifica is composed of 183,052 bp and follows the canonical quadripartite structure, synteny, and gene composition of other angiosperms. Exceptionally large inverted repeat (IR) regions are responsible for the uncommon length of the genome. At least four events of IR expansion were observed among the seven Bignoniaceae species compared, suggesting multiple expansions of the IRs over the SC regions in the family. A comparison with 6,231 other complete plastomes of flowering plants available on GenBank revealed that the plastome of B. magnifica is the longest Lamiid plastome described to date. The newly generated plastid genome was used as a source of selected genes. These genes were combined with orthologous regions sampled from other species of Bignoniaceae and all gene alignments concatenated to infer a phylogeny of the family. The tree recovered is consistent with known relationships within the Bignoniaceae.

Assuntos

RESUMO

The plant family Bignoniaceae is a conspicuous and charismatic element of the tropical flora. The family has a complex taxonomic history, with substantial changes in the classification of the group during the past two centuries. Recent re-classifications at the tribal and generic levels have been largely possible by the availability of molecular phylogenies reconstructed using Sanger sequencing data. However, our complete understanding of the systematics, evolution, and biogeography of the family remains incomplete, especially due to the low resolution and support of different portions of the Bignoniaceae phylogeny. To overcome these limitations and increase the amount of molecular data available for phylogeny reconstruction within this plant family, we developed a bait kit targeting 762 nuclear genes, including 329 genes selected specifically for the Bignoniaceae; 348 genes obtained from the Angiosperms353 with baits designed specifically for the family; and, 85 low-copy genes of known function. On average, 77.4% of the reads mapped to the targets, and 755 genes were obtained per species. After removing genes with putative paralogs, 677 loci were used for phylogenetic analyses. On-target genes were compared and combined in the Exon-Only dataset, and on-target + off-target regions were combined in the Supercontig dataset. We tested the performance of the bait kit at different taxonomic levels, from family to species-level, using 38 specimens of 36 different species of Bignoniaceae, representing: 1) six (out of eight) tribal level-clades (e.g., Bignonieae, Oroxyleae, Tabebuia Alliance, Paleotropical Clade, Tecomeae, and Jacarandeae), only Tourrettieae and Catalpeae were not sampled; 2) all 20 genera of Bignonieae; 3) seven (out of nine) species of Dolichandra (e.g., D. chodatii, D. cynanchoides, D. dentata, D. hispida, D. quadrivalvis, D. uncata, and D. uniguis-cati), only D. steyermarkii and D. unguiculata were not sampled; and 4) three individuals of Dolichandra unguis-cati. Our data reconstructed a well-supported phylogeny of the Bignoniaceae at different taxonomic scales, opening new perspectives for a comprehensive phylogenetic framework for the family as a whole.

RESUMO

The chloroplast genome of Tabebuia nodosa is described and characterized here. This species is endemic to the Chaco and the first species of Tabebuia to have its organelle genome sequenced, providing a genomic resource for phylogenetic inferences. The plastome of T. nodosa is 158,454 bp in length, with a large single-copy of 85,406 bp, a small single-copy of 12,785 bp, and inverted repeats of 30,116 bp each. It contains 131 genes, with 86 protein-coding genes, 37 tRNA, and 8 rRNA. Overall, the GC content is 38.2%. The T. nodosa plastome resembles the structural organization of plastomes commonly found in flowering plants, including those of other genera of Bignoniaceae. A phylogenetic analysis combining a subset of Bignoniaceae plastomes confirms the placement of T. nodosa within the Tabebuia alliance with maximum support.

RESUMO

Dolichandra is a genus of lianas found in dry and wet Neotropical forests. The genus currently includes eight species and is well characterized by molecular and morphological synapomorphies. Here, Macfadyenahispida (DC.) Seemann is removed from synonomy with Dolichandrauncata (Andrews) L.G. Lohmann based on the presence of the hispid indument, vinaceus ovary, long fruits, and winged seeds. The combination Dolichandrahispida (DC.) L.H. Fonseca & L.G. Lohmann, comb. nov. is proposed, increasing the number of accepted species of Dolichandra to nine. A taxonomic key for all species of Dolichandra is presented.

RESUMO

PREMISE OF THE STUDY: New primers were developed for Bignonieae to enable phylogenetic studies within this clade using herbarium samples. • METHODS AND RESULTS: Internal primers were designed based on available sequences of the plastid ndhF gene and the rpl32-trnL intergenic spacer region, and the nuclear gene PepC. The resulting primers were used to amplify DNA extracted from herbarium materials. High-quality data were obtained from herbarium samples up to 53 yr old. • CONCLUSIONS: The standardized methodology allows the inclusion of herbarium materials as alternative sources of DNA for phylogenetic studies in Bignonieae.