34 research outputs found
Phylogenomic insight into dysploidy, speciation, and plastome evolution of a small Mediterranean genus Reichardia (Cichorieae; Asteraceae)
Reichardia Roth is a small Mediterranean genus comprising ten homogeneous species with basic
chromosome numbers of 7, 8, and 9. To assess the plastid genome evolution and diferentiation of
Reichardia species, we assembled the complete plastome sequences of seven Reichardia and two
Launaea species and conducted various phylogenomic analyses comparatively with nuclear ribosomal
DNA ITS sequences. Reichardia and Launaea plastomes were highly conserved in gene content and
order, containing 130 genes. Plastid phylogenomic reconstruction strongly suggested that Reichardia
was a sister to Launaea, and its common ancestor initially diverged into two major lineages: the
frst containing species with n= 8 chromosomes exclusively, and the other with n= 9, 8, and 7
chromosomes. Although the ancestral Reichardia karyotype was suggested to most likely be n= 9 from
ancestral chromosome number reconstruction, the pattern of descending dysploidy indicated by the
phylogenetic trees based on nuclear ribosomal DNA ITS was less evident in the trees based on the
plastome. Possible reasons for these fndings are discussed
Sow Thistle Chloroplast Genomes: Insights into the Plastome Evolution and Relationship of Two Weedy Species, Sonchus asper and Sonchus oleraceus (Asteraceae)
Prickly sow thistle, Sonchus asper (L.) Hill, and common sow thistle, Sonchus oleraceus L., are
noxious weeds. Probably originating from the Mediterranean region, they have become widespread
species. They share similar morphology and are closely related. However, they differ in their
chromosome numbers and the precise relationship between them remains uncertain. Understanding
their chloroplast genome structure and evolution is an important initial step toward determining
their phylogenetic relationships and analyzing accelerating plant invasion processes on a global scale.
We assembled four accessions of chloroplast genomes (two S. asper and two S. oleraceus) by the next
generation sequencing approach and conducted comparative genomic analyses. All the chloroplast
genomes were highly conserved. Their sizes ranged from 151,808 to 151,849 bp, containing 130 genes
including 87 coding genes, 6 rRNA genes, and 37 tRNA genes. Phylogenetic analysis based on the
whole chloroplast genome sequences showed that S. asper shares a recent common ancestor with
S. oleraceus and suggested its likely involvement in a possible amphidiploid origin of S. oleraceus.
In total, 79 simple sequence repeats and highly variable regions were identified as the potential
chloroplast markers to determine genetic variation and colonization patterns of Sonchus species
Plastid Phylogenomics of Dendroseris (Cichorieae; Asteraceae): Insights Into Structural Organization and Molecular Evolution of an Endemic Lineage From the Juan Fernández Islands
This work is licensed under a Creative Commons Attribution 4.0 International License.Dendroseris D. Don comprises 11 species endemic to the Juan Fernández islands in Chile. They demonstrate spectacular and unusual growth forms of rosette trees with extremely variable morphology and occupy wide ecological ranges on the islands. These unique plants are now highly threatened with extinction with very small population sizes, typically consisting of 10 or fewer individuals in wild. Despite morphological and ecological divergence among species of Dendroseris, their monophyly has been supported in previous studies, but with little resolution among subgeneric groups. We assembled seven complete plastome sequences from seven species of Dendroseris, including representatives from three subgenera, and carried out comparative phylogenomic analyses. The plastomes are highly conserved in gene content and order, with size ranging from 152,199 to 152,619 bp and containing 130 genes (87 coding genes, 6 rRNA genes, and 37 tRNA genes). Plastid phylogenomic analyses based on both the complete plastome sequences and 81 concatenated coding genes only show Dendroseris nested within Sonchus sensu lato, and also that inter-subgeneric relationships are fully resolved. Subg. Phoenicoseris is resolved as sister to the remaining species of the genus and a sister relationship between the two subgenera Dendroseris and Rea. Ten mutation hotspots from LSC and SSC regions and variable SSRs are identified as potential chloroplast markers for future phylogenetic and phylogeographic studies of Sonchus and related groups.Basic Science Research Program through the National Research Foundation of Korea (NRF) (NRF-2019R1A2C2009841
Efficacy and safety of BVAC-C in HPV type 16- or 18–positive cervical carcinoma who failed 1st platinum-based chemotherapy: a phase I/IIa study
BackgroundBVAC-C, a B cell– and monocyte-based immunotherapeutic vaccine transfected with recombinant HPV E6/E7, was well tolerated in HPV–positive recurrent cervical carcinoma patients in a phase I study. This phase IIa study investigates the antitumor activity of BVAC-C in patients with HPV 16– or 18–positive cervical cancer who had experienced recurrence after a platinum-based combination chemotherapy.Patients and methodsPatients were allocated to 3 arms; Arm 1, BVAC-C injection at 0, 4, 8 weeks; Arm 2, BVAC-C injection at 0, 4, 8, 12 weeks; Arm 3, BVAC-C injection at 0, 4, 8, 12 weeks with topotecan at 2, 6, 10, 14 weeks. Primary endpoints were safety and objective response rate (ORR) as assessed by an independent radiologist according to Response Evaluation Criteria in Solid Tumors version 1.1. Secondary endpoints included the disease control rate (DCR), duration of response (DOR), progression-free survival (PFS), and overall survival (OS).ResultsOf the 30 patients available for analysis, the ORR was 19.2% (Arm 1: 20.0% (3/15), Arm 2: 33.3% (2/6), Arm3: 0%) and the DCR was 53.8% (Arm 1: 57.1%, Arm 2: 28.6%, Arm3: 14.3%). The median DOR was 7.5 months (95% CI 7.1–not reported), the median PFS was 5.8 months (95% CI 4.2–10.3), and the median OS was 17.7 months (95% CI 12.0–not reported). All evaluated patients showed not only inflammatory cytokine responses (IFN-γ or TNF-α) but also potent E6/E7-specific T cell responses upon vaccinations. Immune responses of patients after vaccination were correlated with their clinical responses.ConclusionBVAC-C represents a promising treatment option and a manageable safety profile in the second-line setting for this patient population. Further studies are needed to identify potential biomarkers of response.Clinical trial registrationClinicalTrials.gov, identifier NCT02866006
The complete chloroplast genome of Korean Pyrus ussuriensis Maxim. (Rosaceae): providing genetic background of two types of P. ussuriensis
Pyrus ussuriensis Maxim. is one of the most important pear species cultivated in Asia, grown in northern China, far-east Russia, Korea, and Japan. Here we completed the chloroplast genome of wild P. ussuriensis collected in Bonghwa-gun, Korea, which was 159,986 bp in length consisting of four subregions: 87,947 bp of large single copy (LSC) and 19,255 bp of small single copy (SSC) regions are separated by 26,392 bp of inverted repeat (IR) regions. The genome contained a total of 130 genes including 85 protein-coding genes, eight rRNAs, and 37 tRNAs. The overall GC content was 36.5% and those in the LSC, SSC, and IR regions were 34.2%, 30.4%, and 42.6%, respectively. Phylogenetic analysis of 14 Pyrus chloroplast genomes provided the diverse genetic background for wild P. ussuriensis populations in Korea by confirming that wild P. ussuriensis sequenced in this study contained Pyrus pyrifolia type plastome. It revealed substantial sequence variations up to 121 single nucleotide polymorphisms and 781 insertions and deletions against another wild accession of P. ussuriensis (P. ussuriensis type) collected in Mt. Hambaek, Korea
Phylogeography and Ecological Niche Modeling Reveal Reduced Genetic Diversity and Colonization Patterns of Skunk Cabbage (Symplocarpus foetidus; Araceae) From Glacial Refugia in Eastern North America
Alternating glacial and interglacial periods during the Quaternary have dramatically affected the distribution and population genetic structure of plant and animal species throughout the northern hemisphere. Surprisingly, little is known about the post-glacial recolonization history of wetland herbaceous perennials that are widely distributed in the understory of deciduous or mixed deciduous-evergreen forests in eastern North America. In this study, we investigated infraspecific variation among 32 populations of skunk cabbage, Symplocarpus foetidus, to test the hypothesis that the extant species diversity of skunk cabbage is the result of a post-glacial range expansion from southern refugia during the Quaternary Ice Age. A total of 4041 base pairs (bp) of the chloroplast intergenic spacer region (cpDNA) was sequenced from 485 individuals sampled from glaciated (18 populations, 275 individuals) and unglaciated (14 populations, 210 individuals) regions east and west of the Appalachian Mountains. Haplotype number, haplotype diversity, and nucleotide diversity were calculated, and genetic variation within and among populations was assessed by analysis of molecular variance (AMOVA). The geographic pattern of genetic differentiation was further investigated with a spatial analysis of molecular variance (SAMOVA). A total of eight haplotypes and three genetic groups (SAMOVA) were recovered and a much higher haplotype number (eight haplotypes) and haplotype diversity (0.7425) was observed in unglaciated compared to glaciated populations (five haplotypes, haplotype diversity = 0.6099). All haplotypes found in glaciated regions represented a subset of haplotypes found in unglaciated regions. Haplotypes of S. foetidus likely diverged during the Tertiary (mid-Miocene and late Pliocene), predating the last glacial maximum (LGM). Predictions based on ecological niche modeling (ENM) suggested that there was considerably less suitable habitat for skunk cabbage during the LGM, and the habitat range was further south compared to the current distribution. Reduced variation and a subset of haplotypes in glaciated regions suggest a founder effect associated with range expansion via long-distance seed dispersal. Our results do not support the “Driftless Area” scenario for the northern refugium, rather the data suggest a “Northeastern” refugium near the southernmost extent of the LGM
Characterization of the complete chloroplast genome of the woody sow-thistle, Sonchus leptocephalus (Asteraceae) endemic to the Canary Islands
Sonchus leptocephalus belongs to a core member of the woody Sonchus alliance endemic to the Macaronesian Islands in the Atlantic Ocean. The alliance has been subject to intensive investigations of adaptive radiation on oceanic islands. As an attempt to fully understand the patterns and processes of evolution in this group, we determined the complete chloroplast genome of S. leptocephalus endemic to the Canaries. It was 152,406 bp in length, comprising 84,331 bp of large single copy and 18,583 bp of small single copy separated by 24,746 bp of inverted repeats. A total of 130 genes were determined including 87 protein-coding genes, 6 ribosomal RNA, and 37 transfer RNA genes. Phylogenetic analysis confirmed its position within the woody Sonchus alliance
Table_3_Phylogeography and Ecological Niche Modeling Reveal Reduced Genetic Diversity and Colonization Patterns of Skunk Cabbage (Symplocarpus foetidus; Araceae) From Glacial Refugia in Eastern North America.docx
<p>Alternating glacial and interglacial periods during the Quaternary have dramatically affected the distribution and population genetic structure of plant and animal species throughout the northern hemisphere. Surprisingly, little is known about the post-glacial recolonization history of wetland herbaceous perennials that are widely distributed in the understory of deciduous or mixed deciduous-evergreen forests in eastern North America. In this study, we investigated infraspecific variation among 32 populations of skunk cabbage, Symplocarpus foetidus, to test the hypothesis that the extant species diversity of skunk cabbage is the result of a post-glacial range expansion from southern refugia during the Quaternary Ice Age. A total of 4041 base pairs (bp) of the chloroplast intergenic spacer region (cpDNA) was sequenced from 485 individuals sampled from glaciated (18 populations, 275 individuals) and unglaciated (14 populations, 210 individuals) regions east and west of the Appalachian Mountains. Haplotype number, haplotype diversity, and nucleotide diversity were calculated, and genetic variation within and among populations was assessed by analysis of molecular variance (AMOVA). The geographic pattern of genetic differentiation was further investigated with a spatial analysis of molecular variance (SAMOVA). A total of eight haplotypes and three genetic groups (SAMOVA) were recovered and a much higher haplotype number (eight haplotypes) and haplotype diversity (0.7425) was observed in unglaciated compared to glaciated populations (five haplotypes, haplotype diversity = 0.6099). All haplotypes found in glaciated regions represented a subset of haplotypes found in unglaciated regions. Haplotypes of S. foetidus likely diverged during the Tertiary (mid-Miocene and late Pliocene), predating the last glacial maximum (LGM). Predictions based on ecological niche modeling (ENM) suggested that there was considerably less suitable habitat for skunk cabbage during the LGM, and the habitat range was further south compared to the current distribution. Reduced variation and a subset of haplotypes in glaciated regions suggest a founder effect associated with range expansion via long-distance seed dispersal. Our results do not support the “Driftless Area” scenario for the northern refugium, rather the data suggest a “Northeastern” refugium near the southernmost extent of the LGM.</p