39 research outputs found

    De novo sequencing and characterization of floral transcriptome in two species of buckwheat (Fagopyrum)

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    <p>Abstract</p> <p>Background</p> <p>Transcriptome sequencing data has become an integral component of modern genetics, genomics and evolutionary biology. However, despite advances in the technologies of DNA sequencing, such data are lacking for many groups of living organisms, in particular, many plant taxa. We present here the results of transcriptome sequencing for two closely related plant species. These species, <it>Fagopyrum esculentum </it>and <it>F. tataricum</it>, belong to the order Caryophyllales - a large group of flowering plants with uncertain evolutionary relationships. <it>F. esculentum </it>(common buckwheat) is also an important food crop. Despite these practical and evolutionary considerations <it>Fagopyrum </it>species have not been the subject of large-scale sequencing projects.</p> <p>Results</p> <p>Normalized cDNA corresponding to genes expressed in flowers and inflorescences of <it>F. esculentum </it>and <it>F. tataricum </it>was sequenced using the 454 pyrosequencing technology. This resulted in 267 (for <it>F. esculentum</it>) and 229 (<it>F. tataricum</it>) thousands of reads with average length of 341-349 nucleotides. <it>De novo </it>assembly of the reads produced about 25 thousands of contigs for each species, with 7.5-8.2× coverage. Comparative analysis of two transcriptomes demonstrated their overall similarity but also revealed genes that are presumably differentially expressed. Among them are retrotransposon genes and genes involved in sugar biosynthesis and metabolism. Thirteen single-copy genes were used for phylogenetic analysis; the resulting trees are largely consistent with those inferred from multigenic plastid datasets. The sister relationships of the Caryophyllales and asterids now gained high support from nuclear gene sequences.</p> <p>Conclusions</p> <p>454 transcriptome sequencing and <it>de novo </it>assembly was performed for two congeneric flowering plant species, <it>F. esculentum </it>and <it>F. tataricum</it>. As a result, a large set of cDNA sequences that represent orthologs of known plant genes as well as potential new genes was generated.</p

    One thousand plant transcriptomes and the phylogenomics of green plants

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    Abstract: Green plants (Viridiplantae) include around 450,000–500,000 species1, 2 of great diversity and have important roles in terrestrial and aquatic ecosystems. Here, as part of the One Thousand Plant Transcriptomes Initiative, we sequenced the vegetative transcriptomes of 1,124 species that span the diversity of plants in a broad sense (Archaeplastida), including green plants (Viridiplantae), glaucophytes (Glaucophyta) and red algae (Rhodophyta). Our analysis provides a robust phylogenomic framework for examining the evolution of green plants. Most inferred species relationships are well supported across multiple species tree and supermatrix analyses, but discordance among plastid and nuclear gene trees at a few important nodes highlights the complexity of plant genome evolution, including polyploidy, periods of rapid speciation, and extinction. Incomplete sorting of ancestral variation, polyploidization and massive expansions of gene families punctuate the evolutionary history of green plants. Notably, we find that large expansions of gene families preceded the origins of green plants, land plants and vascular plants, whereas whole-genome duplications are inferred to have occurred repeatedly throughout the evolution of flowering plants and ferns. The increasing availability of high-quality plant genome sequences and advances in functional genomics are enabling research on genome evolution across the green tree of life

    Tulipa toktogulica (Liliaceae), a cryptic, endangered new species from the western Tien-Shan, Kyrgyzstan

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    Tulipa toktogulica (T. sect. Kolpakowskianae; Liliaceae) is a cryptic new species from the Toktogul area of the Jalal-Abad Region, Kyrgyzstan. It is similar to T. talassica, with which it shares the characteristically elongated tunic, but it is genetically and geographically distinct. It has a combination of morphological traits shared between the closely related species T. talassica, T. tetraphylla and T. ferganica, but the combination of its traits is unique. Unlike most other members of the genus, this new species has a scent. It is here also assessed as endangered due to its narrow range and continuing threats from overgrazing.</jats:p
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