Project description:The genus Flaveria has been extensively used as a model to study the evolution of C4 photosynthesis as it contains both C3 and C4 species as well as a number of species that exhibit intermediate types of photosynthesis. The current phylogenetic tree of the Flaveria genus contains 21 of the 23 known Flaveria species and has been constructed using a combination of morphologicial data and three non-coding DNA sequences (nuclear encoded ETS, ITS and chloroplast encoded trnl-F). However, recent studies have suggested that phylogenetic trees inferred using a small number of molecular sequences may often be incorrect. Moreover, studies in other genera have often shown substantial differences between trees inferred using morphological data and those using molecular sequence. To provide new insight into the phylogeny of the genus Flaveria we utilize RNA-Seq data to construct a multi-gene concatenated phylogenetic tree of 17 Flaveria species. Furthermore, we use this new data to identify 14 C4 specific non-synonymous mutation sites, 12 of which (86%) can be independently verified by public sequence data. We propose that the data collection method provided in this study can be used as a generic method for facilitating phylogenetic tree reconstruction in the absence of reference genomes for the target species. 18 Flaveria sample including 11 species are sequenced, other three samples were also sequenced as out-group. In all, 21 samples.
Project description:The genus Flaveria has been extensively used as a model to study the evolution of C4 photosynthesis as it contains both C3 and C4 species as well as a number of species that exhibit intermediate types of photosynthesis. The current phylogenetic tree of the Flaveria genus contains 21 of the 23 known Flaveria species and has been constructed using a combination of morphologicial data and three non-coding DNA sequences (nuclear encoded ETS, ITS and chloroplast encoded trnl-F). However, recent studies have suggested that phylogenetic trees inferred using a small number of molecular sequences may often be incorrect. Moreover, studies in other genera have often shown substantial differences between trees inferred using morphological data and those using molecular sequence. To provide new insight into the phylogeny of the genus Flaveria we utilize RNA-Seq data to construct a multi-gene concatenated phylogenetic tree of 17 Flaveria species. Furthermore, we use this new data to identify 14 C4 specific non-synonymous mutation sites, 12 of which (86%) can be independently verified by public sequence data. We propose that the data collection method provided in this study can be used as a generic method for facilitating phylogenetic tree reconstruction in the absence of reference genomes for the target species.
Project description:Diversification of defense-related compounds is a plant defense mechanism against the diverse array of natural enemies in the course of evolution, and is known to involve various sources of tissue. Here a large-scale survey of gene expression is conducted from three different sources of tissue; needles, phloem with the attached bark, and xylem, with an emphasis on the expression of the secondary metabolites of the core phenylpropanoid pathway and derivative pathways, taken together as phenolic defense-related compounds. Five species of spruce; P. abies, P. glauca, P. jezoensis, P. mariana, and P. omorika, spanning much of their known phylogeny, are chosen for cross-species microarray hybridizations. The objectives are: first) to explore the tissue-related differences in the expression of phenolic genes and their coherent role in tree defense; second) to describe the diversification trends in the expression of phenolic gene families with respect to their position in the pathway; and third) to infer the mode of evolution underlying the expression of the selected genes.
Project description:The genomes of three newly isolated Dehalococcoides strains (11a, 11a5 and MB) were compared against known genomes in the Dehalococcoides genus via a microarray targeting four sequenced Dehalococcoides strains (195, CBDB1, BAV1, and VS). All three strains exhibit different dechlorination patterns, with strains 11a dechlorinating TCE to ethene, 11a5 dechlorinating TCE to VC and MB dechlorinating PCE only to isomers of DCE. Hybridization of their respective genomic DNA to the microarrays showed that the genomes of strains 11a and 11a5 show great similarity to each other and to strains CBDB1 and BAV1 of the Pinellas subgroup, while strain MB shows strong genome similarity to members of the Cornell subgroup. All genes within the respective subgroups that were not detected by microarray are within the respective high plasticity regions or integrated elements of the sequenced strains. A large number of reductive dehalogenase (RDase)-encoding genes are present within each genome, and the presence of the vcrA and tceA genes in strains 11a and 11a5 respectively, and the absence of any of the four functionally-characterized chlorinated ethene RDases (pceA, tceA, vcrA, bvcA) within strain MB appear to dictate chlorinated ethene usages regardless of the respective core genome phylogeny of the three strains. Considering the current data set together with previous comparative genomics results from application of the Dehalococcoides genus microarray to two other un-sequenced strains, the observed incongruence between the core genome phylogeny and chlorinated ethene usage of Dehalococcoides strains is likely driven by horizontal gene transfer of functional RDases. The other genomic features that are repeatedly observed in the microarray analyses of all five un-sequenced Dehalococcoides strains as well as the environmental implications on this work are presented in this study. The genomic DNA (gDNA) of each culture was analyzed in triplicate. gDNA from the two newly isolated Dehalococcoides strains 11a and 11a5 were analyzed.
Project description:The páramo ecosystem has the highest rate of diversification across plant lineages on earth, of which the genus Espeletia (Asteraceae) is a prime example. The current distribution and molecular phylogeny of Espeletia suggest the influence of Andean geography and past climatic fluctuations on the diversification of this genus. However, molecular markers have failed to reveal subtle biogeographical trends in Espeletia diversification, and metabolomic evidence for allopatric segregation in plants has never been reported. Here, we present for the first time a metabolomics approach based on liquid chromatography-mass spectrometry for revealing subtle biogeographical trends in Espeletia diversification. We demonstrate that Espeletia lineages can be distinguished by means of different metabolic fingerprints correlated to the country of origin on a global scale and to the páramo massif on a regional scale. Distinctive patterns in the accumulation of secondary metabolites according to the main diversification centers of Espeletia are also identified and a comprehensive phytochemical characterization is reported. These findings demonstrate that a variation in the metabolic fingerprints of Espeletia lineages followed the biogeography of this genus, suggesting that our untargeted metabolomics approach can be potentially used as a model to understand the biogeographic history of additional plant groups in the páramo ecosystem.
Project description:Phylogenetic, microbiological and comparative genomic analysis was used to examine the diversity among members of the genus Caldicellulosiruptor with an eye towards the capacity of these extremely thermophilic bacteria for degrading the complex carbohydrate content of plant biomass. Seven species from this genus (C. saccharolyticus, C. bescii (formerly Anaerocellum thermophilum), C. hydrothermalis, C. owensensis, C. kronotskyensis, C. lactoaceticus, and C. kristjanssonii) were compared on the basis of 16S rRNA phylogeny and cross-species DNA-DNA hybridization to a whole genome C. saccharolyticus oligonucleotide microarray. Growth physiology of the seven Caldicellulosiruptor species on a range of carbohydrates showed that, while all could be cultivated on acid pre-treated switchgrass, only C. saccharolyticus, C. besci, C. kronotskyensis, and C. lactoaceticus were capable of hydrolyzing Whatman No. 1 filter paper. Two-dimensional gel electrophoresis of the secretomes from cells grown on microcrystalline cellulose revealed that species capable of crystalline cellulose hydrolysis also had diverse secretome fingerprints. The two-dimensional secretome of C. saccharolyticus revealed a prominent S-layer protein that appears to be also indicative of highly cellulolytic Caldicellulosiruptor species, suggesting a possible role in cell-substrate interaction. These growth physiology results were also linked to glycoside hydrolase and carbohydrate-binding module inventories for the seven bacteria, deduced from draft genome sequence information. These preliminary inventories indicated that the absence of a single glycoside hydrolase family and carbohydrate binding motif family appear to be responsible for some Caldicellulosiruptor species’ diminished cellulolytic capabilities. Overall, the genus Caldicellulosiruptor appears to contain more genomic and physiological diversity than previously reported, and is well suited for biomass deconstruction applications.