Revised molecular phylogeny, global biogeography, and diversification of palms subfamily Coryphoideae (Arecaceae) based on low copy nuclear and plastid regions.

Coryphoideae are palmate-leaved palms from the family Arecaceae consisting of 46 genera representing 421 species. Although several phylogenetic analyses based on different genomic regions have been carried out on Coryphoideae, a fully resolved molecular phylogenetic tree has not been reported yet. To achieve this, we applied two phylogenetic reconstruction methods: Maximum Likelihood and Bayesian Inference, using amplified sampling by retrieving chloroplast and nuclear DNA sequences from NCBI and adding newly produced sequences from Indian accession into the dataset. The same dataset (chloroplast + nuclear DNA sequences) was used to estimate divergence times and the evolutionary history of Coryphoideae with a Bayesian uncorrelated, lognormal relaxed-clock approach and a Statistical Divergence-Vicariance Analysis method, respectively. The phylogenetic analyses based on a combined chloroplast and nuclear DNA sequence dataset showed well-resolved relationships within the subfamily. Both phylogenetic trees divide Coryphoideae into two main groups: CSPT (Crysophileae, Sabaleae, Phoeniceae, and Trachycarpeae) and the Syncarpous group. These main groups are segregated into eight tribes (Trachycarpeae, Phoeniceae, Sabaleae, Crysophileae, Borasseae, Corypheae, Caryoteae, and Chuniophoeniceae) and four subtribes (Rhapidine, Livistoninae, Hyphaeninae, and Lataniinae) with strong support-values. Most previously unresolved and doubtful relationships within tribes Trachycarpeae and Crysophilieae are now resolved and well-supported. The reconstructed phylogenetic trees support all previous systematic revisions of the subfamily. All Indian sampled species of Arenga, Bentinckia, Hyphaene, and Trachycarpus show close relation with their respective congeneric species. Molecular dating results and integration of biogeography suggest that Coryphoideae originated in Laurasia at ~95.12 Ma and then diverged into the tropical and subtropical regions of the whole world. This study offers the correct combination of nuclear and plastid regions to test the current and future systematic revisions.

Phylogenetic Analysis and Flower Color Evolution of the Subfamily Linoideae (Linaceae).

The taxonomy of the subfamily Linoideae at the intergeneric and section levels has been questioned throughout the years, and the evolution of floral characters remains poorly understood. In particular, the evolution of flower color is still uncertain, despite its ecological importance and being one of the most variable and striking traits in Angiospermae. We evaluated the phylogenetic relationships of the genera and sections and used the phylogeny to reconstruct the ancestral state of flower color. The results suggest reevaluating the taxonomic status of segregated genera and re-incorporating them into Linum. Four of the five sections currently accepted were recovered as monophyletic (Cathartolinum, Dasylinum, Linum, and Syllinum). We propose accepting the section Stellerolinon and reevaluating Linopsis, whose representatives were recovered in three separate clades. The ancestral flower color for Linoideae was yellow-white. The flower colors purple and yellow-white were recovered at the deepest nodes of the two main clades. Pink, blue, and red colors were the most recent to evolve. These results appear to be related to diversification events, biogeographical history, and ecological aspects of the subfamily. Our reconstruction constitutes the first plausible scenario that explores the evolution of flower color, leading to new testable hypotheses for future research on the flax group.

Patterns of Species Richness and Distribution of the Genus Laelia s.l. vs. Laelia s.s. (Laeliinae: Epidendroideae: Orchidaceae) in Mexico: Taxonomic Contribution and Conservation Implications.

Laelia is an endemic genus of the neotropical region, with the greatest richness occurring in Mexico. A recent phylogenetic study transferred some Mexican laelias to the genus Schomburgkia, which has generated debate. The aim of the present study was to analyze the patterns of species richness and endemism and the current and potential geographic distributions of the taxa of Laelia s.l., as well as the putative Laelia s.s., distributed in Mexico as part of an exploratory evaluation of the generic limits to sheds light on the taxonomic debate and generate baselines to guide conservation efforts. A database was generated with information from herbarium specimens and publications. The species richness was estimated by political division, biomes, and elevation. The endemism was analyzed by political division and using the weighted and corrected weighted endemism indices. Geographic data, climatic, and topographic variables were used to predict the distributions with the maximum entropy algorithm. The results supported the proposal to transfer some species to the genus Schomburgkia. Some areas of the Sierra Madre del Sur and Oriental should be included as priority areas in the conservation strategies of Laelia. This study highlights the importance of the taxonomy, distribution, and hotspots in diversity conservation.

Anti-Virulence Properties of Plant Species: Correlation between In Vitro Activity and Efficacy in a Murine Model of Bacterial Infection.

Several plant extracts exhibit anti-virulence properties due to the interruption of bacterial quorum sensing (QS). However, studies on their effects at the preclinical level are scarce. Here, we used a murine model of abscess/necrosis induced by Pseudomonas aeruginosa to evaluate the anti-pathogenic efficacy of 24 plant extracts at a sub-inhibitory concentration. We analyzed their ability to inhibit QS-regulated virulence factors such as swarming, pyocyanin production, and secretion of the ExoU toxin via the type III secretion system (T3SS). Five of the seven extracts with the best anti-pathogenic activity reduced ExoU secretion, and the extracts of Diphysa americana and Hibiscus sabdariffa were identified as the most active. Therefore, the abscess/necrosis model allows identification of plant extracts that have the capacity to reduce pathogenicity of P. aeruginosa. Furthermore, we evaluated the activity of the plant extracts on Chromobacterium violaceum. T3SS (ΔescU) and QS (ΔcviI) mutant strains were assessed in both the abscess/necrosis and sepsis models. Only the ΔescU strain had lower pathogenicity in the animal models, although no activity of plant extracts was observed. These results demonstrate differences between the anti-virulence activity recorded in vitro and pathogenicity in vivo and between the roles of QS and T3S systems as virulence determinants.

Taxonomic revision of the Mesoamerican genus Spathacanthus (Justicieae, Acanthoideae, Acanthaceae).

Spathacanthus is a Mesoamerican genus that occurs in tropical and temperate regions from southern Mexico to Costa Rica; its taxonomy has not been updated for two decades. In view of the fact that a new species has been discovered and that the interspecific affinities in this genus have not been addressed to date, the present study aims to revise the genus Spathacanthus. Specimens of plants of this genus collected from across the distribution range and deposited in herbaria and digital databases were reviewed. In parallel, a cladistic analysis was carried out, based on morphological characters in order to examine relationships between species. Four species of Spathacanthus were recognised: one endemic to Costa Rica, another micro-endemic to Veracruz in Mexico, one more restricted to the forests of Mexico and Guatemala and the last one more widely distributed. Reflecting the previously limited knowledge of the group, many of the specimens that we studied had been misidentified. A key to differentiate these species is provided, supplemented with photographs, drawings and other illustrations, morphological descriptions, synonymy and ecological data. Results, presented here, extend the distribution range of some taxa and a distribution map is presented. The cladistic analysis recovered the genus as monophyletic, showing that S. hoffmannii and S. hahnianus are sister taxa and S. magdalenae was found to be more closely related to S. parviflorus. These plants are vulnerable to degradation and habitat loss.