Phylogeny of the "orchid-like" bladderworts (gen. Utricularia sect. Orchidioides and Iperua : Lentibulariaceae) with remarks on the stolon-tuber system

Background and Aims The "orchid-like" bladderworts (Utricularia) comprise 15 species separated into two sections: Orchidioides and Iperua. These robust and mostly epiphytic species were originally grouped within the section Orchidioides by the first taxonomical systems. These species were later split into two sections when sect. Iperua was proposed. Due to the lack of strong evidence based on a robust phylogenetic perspective, this study presents a phylogenetic proposal based on four different DNA sequences (plastid and nuclear) and morphology to test the monophyly of the two sections. Methods In comparison with all previous phylogenetic studies, the largest number of species across the sections was covered: 11 species from sections Orchidioides and Iperua with 14 species as an external group. Maximum likelihood and Bayesian inferences were applied to DNA sequences of rps16, trnL-F, matK, the internal transcribed spacer (ITS) and three morphological characters: (1) the crest of the corolla; (2) the primary organs in the embryo; and (3) tubers. Additionally, a histochemical analysis of the stolons and tubers is presented from an evolutionary perspective. Key Results The analyses showed the paraphyly of sect. Iperua, since Utricularia humboldtii is more related to the clade of sect. Orchidioides. Utricularia cornigera is grouped in the sect. Iperua clade based on chloroplast DNA sequences, but it is nested to sect. Orchidioides according to ITS dataset. Morphological characters do not support the breaking up of the 'orchid-like' species into two sections, either. Moreover, the stolon-tuber systems of both sections serve exclusively for water storage, according to histological analyses. Conclusions This study provides strong evidence, based on DNA sequences from two genomic compartments (plastid and nucleus) and morphology to group the Utricularia sect. Orchidioides into the sect. Iperua. The tubers are important adaptations for water storage and have been derived from stolons at least twice in the phylogenetic history of 'orchid-like' bladderworts

Polimorfismos no rDNA em uma planta de genoma reduzido Utricularia gibba L. (LENTIBULARIACEAE): evolução em concerto incompleta e sua implicação na inferência filogenética

A planta carnívora Utricularia gibba (Lentibulariaceae) apresenta um genoma reduzido de aproximadamente 82 Mpb e foi empregada no presente estudo para se investigar a diversidade de cópias da região ITS (nrDNA). Uma das características do nrDNA é que suas cópias em tandem apresentam alto grau de similaridade pela ação homogeneizadora da evolução em concerto. Porém, neste estudo foram encontradas variações intragenômicas, intra e interpopulacionais nas regiões ITS em U. gibba. Com o objetivo de elucidar o impacto dos polimorfismos nos espaçadores ITS1, ITS2 e no gene 5,8S nas análises filogenéticas e filogeográficas, foi clonada a região ITS completa de 25 indivíduos de 5 populações, assim obtidos 292 cópias as quais foram analisadas isoladamente cada região (ITS1, 5,8S e ITS2) e em conjunto. Desta forma foram avaliados o comprimento e o conteúdo das regiões, as variações nucleotídicas e haplotípicas e realizadas análises filogenéticas e filogeográficas. Para determinar a funcionalidade das sequências obtidas foram identificados motifs conservados das regiões ITS1 e 5,8S e para os haplótipos da região ITS2 foi confirmada a sua estrutura secundária por transferibilidade das hélices em estruturas secundárias conhecidas de espécies filogeneticamente relacionadas. Assim, as três regiões apresentaram polimorfismos representados em haplótipos para cada sequência. Os resultados sugerem que todos os diferentes haplótipos presentes em U. gibba são cópias funcionais que podem ser usadas como marcadores filogenéticos para o nível de espécie, seja de forma isolada ou a região completa (ITS1+5,8S+ITS2). Entretanto, em análises filogenéticas e filogeográficas podem ser gerados artefatos e histórias evolutivas errôneas quando comparadas populações dentro de uma mesma espécie, dada à presença de haplótipos compartilhados por indivíduos de diferentes populações.The aquatic carnivorous plant, Utricularia gibba (Lentibulariaceae) has a small genome of with approximately 82 Mpb and was used in this work for the variance analysis of the copies diversity of the ribosomal DNA ITS region (nrDNA). One of the nrDNA features is that its its copies in tandem ys have present a high degree of similarity in intra individual and interspecies genomes due the homogenizing action of concerted evolution. However, in this study intragenomic, intra, and inter-populational variations were found in ITS1 + 5.8S + ITS2 ITS regions in individuals and populations evaluated. U. gibba. With the main objectiveaim of to elucidate the impact of polymorphisms of thein the intergenic spacers ITS1, ITS2, and gene 5.8S and ITS2 regions in phylogenetic and phylogeographic analyszes, we was cloned the complete ITS region of 25 individuals from 5 populations, thereby obtained 292 clones copies and internal spacers ITS1 and ITS2 and the 5.8S gene were identified, which were analyzed individually (ITS1, 5.8S, and ITS2) and togetherconcatenated. Thus we evaluate the length and GC concentration of the regions, the nucleotide and haplotype variations and achieved phylogenetic and phylogeographic analyzes were madedinferences. To determine test the functionality of the sequences obtained we were searched and compared conserved motifs in spacer ITS1 and 5.8S gene and the haplotypes of spacer ITS2 was evaluated the ITS2 its secondary structure by transferability of helices in known secondary structures known of closely phylogenetically related species. Thus, the three regions showed polymorphisms represented by generating haplotypes for each region. Thise results suggest that the all different haplotypes present in U. gibba are functional copies that can should be used as phylogenetic markers for species studies, either alone each isolated or the complete ITS region (ITS1 + 5.8S + ITS2). But in phylogenetic and phylogeographical analyszes artifacts and erroneous evolutionary histories can be generated when populations from the same species were compared, in population studies due the presence of haplotypes shared by individuals from different populations. Hence, the present results show the need to analyze the variability of the ITS region before its use as a molecular marker.Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES