Genus

About: Genus is a research topic. Over the lifetime, 68921 publications have been published within this topic receiving 590966 citations. The topic is also known as: monospecies genus & genus (zoology).

A Three-Gene Phylogeny of the Genus Solanum (Solanaceae)

Abstract: Solanum, with approximately 1,500 species, is the largest genus in the Solanaceae and includes economically important species such as the tomato, potato, and eggplant. In part due to its large size and tropical center of diversity, resolving evolutionary relationships across Solanum as a whole has been challenging. In order to identify major clades within Solanum and to gain insight into phylogenetic relationships among these clades, we sampled 102 Solanum species and seven outgroup taxa for three DNA sequence regions (chloroplast ndhF and trnT- F, and nuclear waxy) and analyzed the data using parsimony and Bayesian methods. The same major Solanum clades were identified by each data partition, and the combined analysis provided the best resolved hypothesis of relationships within the genus. Our data suggest that most traditionally recognized Solanum subgenera are not monophyletic. The Thelopodium clade is sister to the rest of Solanum, which is split into two large clades. These two large clades are further divided into at least 10 subclades, for which informal names are provided and morphological synapomorphies are proposed. The identification of these subclades provides a framework for directed sampling in further phylogenetic studies, and identifies natural groups for focused revisionary work.

Cacao and Its Allies, a Taxonomic Revision of the Genus Theobroma

Abstract: "Celebrem etiam per universam Americam multique usua fructum Cacao appellatum." Clusius, 1605. "Cacao nomen barbarum, quo rejecto Theobroma dicta est arbor, cum fructus basin sternat potioni delicatissimae, Baluberrimae, maxime nutrienti, chocolate mexicanis, Europaeis quondam folis Magnatis propriae (ffpotfta rwf 8&av, Vos Deos feci dixit Deus de imperantibus), licet num vilior fact a." Linnaeus, Hort. Cliff. 379. 1737.

The Genus Lactobacillus: A Taxonomic Update

Abstract: Lactic Acid Bacteria (LAB) are a functional group of microorganisms comprising Gram-positive, catalase negative bacteria that produce lactic acid as the major metabolic end-product of carbohydrate fermentation. Among LAB, Lactobacillus is the genus including a high number of GRAS species (Generally Recognized As Safe) and many strains are among the most important bacteria in food microbiology and human nutrition, due to their contribution to fermented food production or their use as probiotics. From a taxonomic point of view, the genus Lactobacillus includes at present (October 2012), 152 validly described species, and it belongs to the family Lactobacillaceae together with genus Pediococcus, with whom it is phylogenetically intermixed. The updated phylogenetic analysis based on 16S rRNA gene sequence revealed that the family is divided into 15 groups of three or more species, 4 couples and 10 single lines of descents. In addition, other taxonomically relevant information for Lactobacillus species was collected. This study aims at updating the taxonomy of the genus Lactobacillus, presenting the phylogenetic structure of the Lactobacillaceae and discussing the clusters as possible nuclei of genera to be described in the future. It is expected that scientists and producers in the field of probiotics could benefit from information reported here about the correct identification procedures and nomenclature of beneficial strains of lactobacilli.

Phylogeny and patterns of floral diversity in the genus Piper (Piperaceae).

Abstract: With ∼1000 species distributed pantropically, the genus Piper is one of the most diverse lineages among basal angiosperms. To rigorously address the evolution of Piper we use a phylogenetic analysis of sequences of the internal transcribed spacers (ITS) of nuclear ribosomal DNA based on a worldwide sample. Sequences from a total of 51 species of Piper were aligned to yield 257 phylogenetically informative sites. A single unrooted parsimony network suggested that taxa representing major geographic areas could potentially form three monophyletic groups: Asia, the South Pacific, and the Neotropics. The position of Pothomorphe was well supported among groups of New World taxa. Simultaneous phylogenetic analysis of an expanded alignment including outgroups suggested that taxa from the South Pacific and Asia formed a monophyletic group, provisionally supporting a single origin of dioecy. Within the Neotropical sister clade, resolution was high and strong bootstrap support confirmed the monophyly of several traditionally recognized infrageneric groups (e.g., Enckea [including Arctottonia], Ottonia, Radula, Macrostachys). In contrast, some of the species representing the highly polytypic subgroup Steffensia formed a clade corresponding to the previously recognized taxon Schilleria, while others were strongly associated with several of the more specialized groups of taxa. The distribution of putatively derived inflorescence and floral character states suggested that both umbellate and solitary axillary inflorescences have multiple origins. Reduction in anther number appears to be associated with highly packaged inflorescences or with larger anther primordia per flower, trends that are consistent with the suppression of later stages of androecial development.