Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 20 de 60
Filter
1.
Int J Mol Sci ; 25(13)2024 Jul 05.
Article in English | MEDLINE | ID: mdl-39000487

ABSTRACT

Oestrogen receptor (ER)-positive breast cancer (BC) is generally well responsive to endocrine therapy. Neoadjuvant endocrine therapy (NAET) is increasingly being used for downstaging ER-positive tumours. This study aims to analyse the effect of NAET on a well-characterised cohort of ER-positive BC with particular emphasis on receptor expression. This is a retrospective United Kingdom (UK) multicentre study of 391 patients who received NAET between October 2012 and October 2020. Detailed analyses of the paired pre- and post-NAET morphological changes and hormone receptor (HR) and human epidermal growth factor receptor 2 (HER2) expression were performed. The median duration of NAET was 86 days, with median survival and overall survival rates of 380 days and 93.4%, respectively. A total of 90.3% of cases achieved a pathological partial response, with a significantly higher rate of response in the HER2-low cancers. Following NAET, BC displayed some pathological changes involving the tumour stroma including central scarring and an increase in tumour infiltrating lymphocytes (TILs) and tumour cell morphology. Significant changes associated with the duration of NAET were observed in tumour grade (30.6% of cases), with downgrading identified in 19.3% of tumours (p < 0.001). The conversion of ER status from positive to low or negative was insignificant. The conversion of progesterone receptor (PR) and HER2 status to negative status was observed in 31.3% and 38.1% of cases, respectively (p < 0.001). HER2-low breast cancer decreased from 63% to 37% following NAET in the paired samples. Significant morphological and biomarker changes involving PR and HER2 expression occurred following NAET. The findings support biomarker testing on pre-treatment core biopsies and post-treatment residual carcinoma.


Subject(s)
Breast Neoplasms , Neoadjuvant Therapy , Receptor, ErbB-2 , Receptors, Estrogen , Humans , Breast Neoplasms/pathology , Breast Neoplasms/metabolism , Breast Neoplasms/drug therapy , Female , Neoadjuvant Therapy/methods , Middle Aged , Receptor, ErbB-2/metabolism , Aged , Adult , Receptors, Estrogen/metabolism , Retrospective Studies , Antineoplastic Agents, Hormonal/therapeutic use , Biomarkers, Tumor/metabolism , Aged, 80 and over
2.
Pathobiology ; 90(1): 31-43, 2023.
Article in English | MEDLINE | ID: mdl-35705026

ABSTRACT

INTRODUCTION: Inflammatory breast cancer (IBC) is an aggressive form of breast cancer with a poorly characterized immune microenvironment. METHODS: We used a five-colour multiplex immunofluorescence panel, including CD68, CD4, CD8, CD20, and FOXP3 for immune microenvironment profiling in 93 treatment-naïve IBC samples. RESULTS: Lower grade tumours were characterized by decreased CD4+ cells but increased accumulation of FOXP3+ cells. Increased CD20+ cells correlated with better response to neoadjuvant chemotherapy and increased CD4+ cells infiltration correlated with better overall survival. Pairwise analysis revealed that both ER+ and triple-negative breast cancer were characterized by co-infiltration of CD20 + cells with CD68+ and CD4+ cells, whereas co-infiltration of CD8+ and CD68+ cells was only observed in HER2+ IBC. Co-infiltration of CD20+, CD8+, CD4+, and FOXP3+ cells, and co-existence of CD68+ with FOXP3+ cells correlated with better therapeutic responses, while resistant tumours were characterized by co-accumulation of CD4+, CD8+, FOXP3+, and CD68+ cells and co-expression of CD68+ and CD20+ cells. In a Cox regression model, response to therapy was the most significant factor associated with improved patient survival. CONCLUSION: Those results reveal a complex unique pattern of distribution of immune cell subtypes in IBC and provide an important basis for detailed characterization of molecular pathways that govern the formation of IBC immune landscape and potential for immunotherapy.


Subject(s)
Breast Neoplasms , Inflammatory Breast Neoplasms , Triple Negative Breast Neoplasms , Humans , Female , Inflammatory Breast Neoplasms/metabolism , Inflammatory Breast Neoplasms/pathology , Breast Neoplasms/pathology , Lymphocytes, Tumor-Infiltrating , Fluorescent Antibody Technique , Forkhead Transcription Factors/genetics , Tumor Microenvironment
3.
Case Rep Oncol ; 15(2): 713-719, 2022.
Article in English | MEDLINE | ID: mdl-36157688

ABSTRACT

We report a case of alpelisib-induced uveitis. A 68-year-old female who had recently been given alpelisib for metastatic breast cancer presented with a 2-week history of bilateral worsening vision with a corresponding acute hypermetropic shift. Her unaided visual acuity was 6/60 in both eyes, with bilateral anterior uveitis, non-granulomatous keratic precipitates, posterior synechiae, and limited fundal view. There was also a mild iris bombe configuration, although the intraocular pressures were normal. Ocular ultrasound revealed bilateral uveal effusion, ciliary body congestion, dense vitreous cells, and exudative retinal detachments. These findings were also confirmed on multimodal imaging with widefield fundus photography (Optos) and optical coherence tomography. Based on the clinical features above, a diagnosis of alpelisib-induced panuveitis was diagnosed. She was then admitted and treated with a 3-day course of intravenous methylprednisolone and intensive topical steroids. Her clinical signs and symptoms started to improve, and she was discharged 4 days later. At 1 week of follow-up, her best-corrected visual acuity was 6/12 in both eyes, with broken posterior synechiae and resolution of exudative retinal detachments. This case highlights the importance of early ophthalmology involvement by the oncology team as oncology therapy can have potential unexpected ocular manifestations.

4.
Histopathology ; 79(1): 47-56, 2021 Jul.
Article in English | MEDLINE | ID: mdl-33423290

ABSTRACT

AIMS: Neoadjuvant endocrine therapy (NAET) is used in the management of oestrogen receptor (ER)-positive breast cancer. The optimal method for histological assessment of response and the effect of NAET on the tumour morphology, grade and molecular profile remain unclear. The aim of this study is to investigate the NAET effect on tumour type, grade and molecular profile by analysing a well-characterised cohort of breast cancer samples in a single large UK tertiary referral centre, and to provide guidance on the pathological assessment of those lesions to inform adjuvant management and prognosis. METHODS AND RESULTS: A single large-institution cohort of 132 patients who received NAET over a 13-year period was identified. Comprehensive clinical, histopathological and follow-up data were collected. A detailed histological review of a subset with residual post-treatment carcinoma was undertaken. Two carcinomas (both of the lobular type) achieved complete pathological response. Central scarring was seen in 49.3% of tumours post-treatment. Significant changes in tumour type (41.6%), tumour grade (downgrading in one-third of tumours), and progesterone receptor (PR) expression (22.3%), with a switch to PR-negative status in 17.6% of cases, were observed. The last of these was associated with an absence of tumour-infiltrating lymphocytes (P = 0.005). Ten per cent of cases showed a change in HER2 expression (P = 0.002). The median patient survival was 60 months, and downgrading of tumours was associated with better overall survival (P = 0.05). CONCLUSIONS: We propose a histological method for assessment of residual carcinoma following NAET, and recommend repeat ER/PR/HER2 testing to inform management and prognosis.


Subject(s)
Breast Neoplasms/drug therapy , Breast Neoplasms/pathology , Estrogen Antagonists/therapeutic use , Neoadjuvant Therapy/methods , Treatment Outcome , Adult , Aged , Aged, 80 and over , Antineoplastic Agents, Hormonal , Breast Neoplasms/genetics , Female , Humans , Middle Aged , Receptors, Estrogen/antagonists & inhibitors
5.
Radiother Oncol ; 142: 52-61, 2020 01.
Article in English | MEDLINE | ID: mdl-31785830

ABSTRACT

BACKGROUND: The optimal sequence of adjuvant chemotherapy and radiotherapy for breast cancer is unknown. SECRAB assesses whether local control can be improved without increased toxicity. METHODS: SECRAB was a prospective, open-label, multi-centre, phase III trial comparing synchronous to sequential chemo-radiotherapy, conducted in 48 UK centres. Patients with invasive, early stage breast cancer were eligible. Randomisation (performed using random permuted block assignment) was stratified by centre, axillary surgery, chemotherapy, and radiotherapy boost. Permitted chemotherapy regimens included CMF and anthracycline-CMF. Synchronous radiotherapy was administered between cycles two and three for CMF or five and six for anthracycline-CMF. Sequential radiotherapy was delivered on chemotherapy completion. Radiotherapy schedules included 40 Gy/15F over three weeks, and 50 Gy/25F over five weeks. The primary outcome was local recurrence at five and ten years, defined as time to local recurrence, and analysed by intention to treat. ClinicalTrials.gov NCT00003893. FINDINGS: Between 02-July-1998 and 25-March-2004, 2297 patients were recruited (1150 synchronous and 1146 sequential). Baseline characteristics were balanced. With 10.2 years median follow-up, the ten-year local recurrence rates were 4.6% and 7.1% in the synchronous and sequential arms respectively (hazard ratio (HR) 0.62; 95% confidence interval (CI): 0.43-0.90; p = 0.012). In a planned sub-group analysis of anthracycline-CMF, the ten-year local recurrence rates difference were 3.5% versus 6.7% respectively (HR 0.48 95% CI: 0.26-0.88; p = 0.018). There was no significant difference in overall or disease-free survival. 24% of patients on the synchronous arm suffered moderate/severe acute skin reactions compared to 15% on the sequential arm (p < 0.0001). There were no significant differences in late adverse effects apart from telangiectasia (p = 0.03). INTERPRETATION: Synchronous chemo-radiotherapy significantly improved local recurrence rates. This was delivered with an acceptable increase in acute toxicity. The greatest benefit of synchronous chemo-radiation was in patients treated with anthracycline-CMF. FUNDING: Cancer Research UK (CR UK/98/001) and Pharmacia.


Subject(s)
Antineoplastic Combined Chemotherapy Protocols/therapeutic use , Neoplasm Recurrence, Local/drug therapy , Neoplasm Recurrence, Local/radiotherapy , Adult , Aged , Anthracyclines/administration & dosage , Antineoplastic Combined Chemotherapy Protocols/administration & dosage , Breast Neoplasms/pathology , Chemoradiotherapy, Adjuvant , Cisplatin/administration & dosage , Disease-Free Survival , Female , Fluorouracil/administration & dosage , Humans , Methotrexate/administration & dosage , Middle Aged , Neoplasm Recurrence, Local/pathology , Neoplasm Staging , Prospective Studies , Treatment Outcome , Young Adult
6.
Healthcare (Basel) ; 7(4)2019 Oct 18.
Article in English | MEDLINE | ID: mdl-31635409

ABSTRACT

Background: Sarcomas are rare and heterogeneous tumours with a large proportion of patients requiring palliative intervention. They are regarded as relatively radioresistant and therefore achieving good palliation with radiation may require larger doses than for more common solid tumour types. Limited data is available regarding appropriate palliative radiotherapy dose fractionation. This case series aims to assess the effectiveness of radiotherapy in providing symptomatic improvement for advanced sarcomas. Method: Data was retrospectively collected for patients treated with palliative radiotherapy between July 2010 and April 2019 at one institution. The primary outcome was documented symptomatic improvement following radiotherapy. Secondary outcome was overall survival. Results: One hundred and five patients had a total of 137 sites treated using 25 different dose fractionation schedules. The median patient age was 54 (range 8-90) years. Treated sites included 114 soft tissue and 23 bone sarcomas. Data on symptomatic improvement was available in 56% and 67% of cases respectively. A total of 70% of soft tissue and 55% of bone sarcoma patients reported symptomatic improvement. Symptomatic response rates appeared to increase to a biological effective dose (BED) of 50Grey4 (Gy4) (alpha beta ratio (α/ß) = 4 for tumour) but did not continue to improve with further rises in dose beyond this. Conclusion: Palliative radiotherapy offers symptomatic improvement for sarcoma patients with two-thirds of patients reporting reduction in symptoms. These results are limited by the heterogeneous study population including different sarcoma subtypes each with a probable different radio-sensitivity, treated with different radiotherapy schedules. Further prospective data collection is needed considering sarcoma subtype radio-sensitivity, to determine appropriate palliative dose fractionation schedules.

7.
Sci Rep ; 9(1): 4454, 2019 03 14.
Article in English | MEDLINE | ID: mdl-30872631

ABSTRACT

Our paper analyzes full plastid DNA sequence data of 202 wild and cultivated diploid potatoes, Solanum section Petota, to explore its phylogenetic utility compared to prior analyses of the same accessions using genome-wide nuclear SNPs, and plastid DNA restriction site data. The present plastid analysis discovered the same major clades as the nuclear data but with some substantial differences in topology within the clades. The considerably larger plastid and nuclear data sets add phylogenetic resolution within the prior plastid DNA restriction site data, highlight plastid/nuclear incongruence that supports hypotheses of hybridization/introgression to help explain the taxonomic difficulty in the section.


Subject(s)
Genome, Plastid , Phylogeny , Solanum/genetics , Diploidy , Genetic Variation , Polymorphism, Single Nucleotide
8.
Proc Natl Acad Sci U S A ; 115(28): E6392-E6393, 2018 07 10.
Article in English | MEDLINE | ID: mdl-29934399
9.
Clin Sarcoma Res ; 8: 6, 2018.
Article in English | MEDLINE | ID: mdl-29610659

ABSTRACT

BACKGROUND: Two national clinical trial groups, United Kingdom Children's Cancer and Leukaemia Group (CCLG) and the German Paediatric Oncology and Haematology Group (GPOH) together undertook a randomised trial, EICESS-92, which addressed chemotherapy options for Ewing's sarcoma. We sought the causes of unexpected survival differences between the study groups. METHODS: 647 patients were randomised. Cox regression analyses were used to compare event-free survival (EFS) and overall survival (OS) between the two study groups. RESULTS: 5-year EFS rates were 43% (95% CI 36-50%) and 57% (95% CI 52-62) in the CCLG and GPOH patients, respectively; corresponding 5-year OS rates were 52% (95% CI 45-59%) and 66% (95% CI 61-71). CCLG patients were less likely to have both surgery and radiotherapy (18 vs. 59%), and more likely to have a single local therapy modality compared to the GPOH patients (72 vs. 35%). Forty-five percent of GPOH patients had pre-operative radiotherapy compared to 3% of CCLG patients. In the CCLG group local recurrence (either with or without metastases) was the first event in 22% of patients compared with 7% in the GPOH group. After allowing for the effects of age, metastases, primary site, histology and local treatment modality, the risk of an EFS event was 44% greater in the CCLG cohort (95% CI 10-89%, p = 0.009), and the risk of dying was 30% greater, but not statistically significant (95% CI 3-74%, p = 0.08). CONCLUSIONS: Unexpected differences in EFS and OS occurred between two patient cohorts recruited within an international randomised trial. Failure to select or deliver appropriate local treatment modalities for Ewing's sarcoma may compromise chances of cure.Trial registration Supported by Deutsche Krebshilfe (Grants No. DKH M43/92/Jü2 and DKH 70-2551 Jü3), and European Union Biomedicine and Health Programme (Grants No. BMH1-CT92-1341 and BMH4-983956), and Cancer Research United Kingdom. Clinical trial information can be found for the following: NCT0000251.

10.
Am J Bot ; 105(1): 60-70, 2018 01.
Article in English | MEDLINE | ID: mdl-29532930

ABSTRACT

PREMISE OF THE STUDY: The species boundaries of wild and cultivated potatoes are controversial, with most of the taxonomic problems in the cultivated potato clade. We here provide the first in-depth phylogenetic study of the cultivated potato clade to explore possible causes of these problems. METHODS: We examined 131 diploid accessions, using 12 nuclear orthologs, producing an aligned data set of 14,072 DNA characters, 2171 of which are parsimony-informative. We analyzed the data to produce phylogenies and perform concordance analysis and goodness-of-fit tests. KEY RESULTS: There is good phylogenetic structure in clades traditionally referred to as clade 1+2 (North and Central American diploid potatoes exclusive of Solanum verrucosum), clade 3, and a newly discovered basal clade, but drastically reduced phylogenetic structure in clade 4, the cultivated potato clade. The results highlight a clade of species in South America not shown before, 'neocardenasii', sister to clade 1+2, that possesses key morphological traits typical of diploids in Mexico and Central America. Goodness-of-fit tests suggest potential hybridization between some species of the cultivated potato clade. However, we do not have enough phylogenetic signal with the data at hand to explicitly estimate such hybridization events with species networks methods. CONCLUSIONS: We document the close relationships of many of the species in the cultivated potato clade, provide insight into the cause of their taxonomic problems, and support the recent reduction of species in this clade. The discovery of the neocardenasii clade forces a reevaluation of a hypothesis that section Petota originated in Mexico and Central America.


Subject(s)
Evolution, Molecular , Phylogeny , Solanum/genetics , Sequence Analysis, DNA , Solanum/classification
11.
Mol Plant ; 11(3): 473-484, 2018 03 05.
Article in English | MEDLINE | ID: mdl-29421339

ABSTRACT

Wild potato species have substantial phenotypic and physiological diversity. Here, we report a comprehensive assessment of wild and cultivated potato species based on genomic analyses of 201 accessions of Solanum section Petota. We sequenced the genomes of these 201 accessions and identified 6 487 006 high-quality single nucleotide polymorphisms (SNPs) from 167 accessions in clade 4 of Solanum section Petota, including 146 wild and 21 cultivated diploid potato accessions with a broad geographic distribution. Genome-wide genetic variation analysis showed that the diversity of wild potatoes is higher than that of cultivated potatoes, and much higher genetic diversity in the agronomically important disease resistance genes was observed in wild potatoes. Furthermore, by exploiting information about known quantitative trait loci (QTL), we identified 609 genes under selection, including those correlated with the loss of bitterness in tubers and those involved in tuberization, two major domesticated traits of potato. Phylogenetic analyses revealed a north-south division of all species in clade 4, not just those in the S. brevicaule complex, and further supported S. candolleanum as the progenitor of cultivated potato and the monophyletic origin of cultivated potato in southern Peru. In addition, we analyzed the genome of S. candolleanum and identified 529 genes lost in cultivated potato. Collectively, the molecular markers generated in this study provide a valuable resource for the identification of agronomically important genes useful for potato breeding.


Subject(s)
Genomics/methods , Plant Breeding , Solanum tuberosum/genetics , Genetic Variation/genetics , Genome, Plant/genetics , Genotype , Phylogeny , Plant Tubers/genetics , Plant Tubers/metabolism , Quantitative Trait Loci/genetics
12.
Front Genet ; 8: 119, 2017.
Article in English | MEDLINE | ID: mdl-28983315

ABSTRACT

DNA-based marker analysis of plant genebank material has become a useful tool in the evaluation of levels of genetic diversity and for the informed use and maintenance of germplasm. In this study, we quantify levels of amplified fragment length polymorphism (AFLP) in representative accessions of wild and cultivated potato species of differing geographic origin, ploidy, and breeding system. We generated 449 polymorphic AFLP fragments in 619 plants, representing multiple plants (16-23) from 17 accessions of 14 potato taxa as well as single plants sampled from available accessions (from 3 to 56) of the same 14 taxa. Intra-accession diversities were compared to those of a synthetic 'taxon-wide' population comprising a single individual from a variable number of available accessions of each sampled taxon. Results confirm the expected considerably lower levels of polymorphism within accessions of self-compatible as compared to self-incompatible taxa. We observed broadly similar levels of 'taxon-wide' polymorphism among self-compatible and self-incompatible species, with self-compatible taxa showing only slightly lower rates of polymorphism. The most diverse accessions were the two cultivated potato accessions examined, the least diverse being the Mexican allohexaploids Solanum demissum and S. iopetalum. Generally allopolyploid self-compatible accessions exhibited lower levels of diversity. Some purported self-incompatible accessions showed relatively low levels of marker diversity, similar to the more diverse self-compatible material surveyed. Our data indicate that for self-compatible species a single plant is highly representative of a genebank accession. The situation for self-incompatible taxa is less clear, and sampling strategies used will depend on the type of investigation. These results have important implications for those seeking novel trait variation (e.g., disease resistance) in gene banks as well as for the selection of individuals for genomics studies. We also show that AFLPs, despite having been largely replaced by other marker types, is highly suitable for the evaluation of within and between accession diversity in genebanks.

13.
Am J Bot ; 104(2): 296-312, 2017 Feb.
Article in English | MEDLINE | ID: mdl-28202452

ABSTRACT

PREMISE OF THE STUDY: We explored the phylogenetic utility of entire plastid DNA sequences in Daucus and compared the results with prior phylogenetic results using plastid and nuclear DNA sequences. METHODS: We used Illumina sequencing to obtain full plastid sequences of 37 accessions of 20 Daucus taxa and outgroups, analyzed the data with phylogenetic methods, and examined evidence for mitochondrial DNA transfer to the plastid (DcMP). KEY RESULTS: Our phylogenetic trees of the entire data set were highly resolved, with 100% bootstrap support for most of the external and many of the internal clades, except for the clade of D. carota and its most closely related species D. syrticus. Subsets of the data, including regions traditionally used as phylogenetically informative regions, provide various degrees of soft congruence with the entire data set. There are areas of hard incongruence, however, with phylogenies using nuclear data. We extended knowledge of a mitochondrial to plastid DNA insertion sequence previously named DcMP and identified the first instance in flowering plants of a sequence of potential nuclear genome origin inserted into the plastid genome. There is a relationship of inverted repeat junction classes and repeat DNA to phylogeny, but no such relationship with nonsynonymous mutations. CONCLUSIONS: Our data have allowed us to (1) produce a well-resolved plastid phylogeny of Daucus, (2) evaluate subsets of the entire plastid data for phylogeny, (3) examine evidence for plastid and nuclear DNA phylogenetic incongruence, and (4) examine mitochondrial and nuclear DNA insertion into the plastid.


Subject(s)
Cell Nucleus/genetics , Daucus carota/genetics , Genome, Mitochondrial/genetics , Genome, Plant/genetics , Genome, Plastid/genetics , Phylogeny , DNA, Chloroplast/genetics , DNA, Mitochondrial/genetics , DNA, Plant/chemistry , DNA, Plant/classification , DNA, Plant/genetics , Daucus carota/classification , Genes, Plant/genetics , Mutagenesis, Insertional , Plant Proteins/genetics , Plastids/genetics , Sequence Analysis, DNA , Species Specificity
14.
BMC Evol Biol ; 16(1): 234, 2016 Oct 28.
Article in English | MEDLINE | ID: mdl-27793080

ABSTRACT

BACKGROUND: The majority of the subspecies of Daucus carota have not yet been discriminated clearly by various molecular or morphological methods and hence their phylogeny and classification remains unresolved. Recent studies using 94 nuclear orthologs and morphological characters, and studies employing other molecular approaches were unable to distinguish clearly many of the subspecies. Fertile intercrosses among traditionally recognized subspecies are well documented. We here explore the utility of single nucleotide polymorphisms (SNPs) generated by genotyping-by-sequencing (GBS) to serve as an effective molecular method to discriminate the subspecies of the D. carota complex. RESULTS: We used GBS to obtain SNPs covering all nine Daucus carota chromosomes from 162 accessions of Daucus and two related genera. To study Daucus phylogeny, we scored a total of 10,814 or 38,920 SNPs with a maximum of 10 or 30 % missing data, respectively. To investigate the subspecies of D. carota, we employed two data sets including 150 accessions: (i) rate of missing data 10 % with a total of 18,565 SNPs, and (ii) rate of missing data 30 %, totaling 43,713 SNPs. Consistent with prior results, the topology of both data sets separated species with 2n = 18 chromosome from all other species. Our results place all cultivated carrots (D. carota subsp. sativus) in a single clade. The wild members of D. carota from central Asia were on a clade with eastern members of subsp. sativus. The other subspecies of D. carota were in four clades associated with geographic groups: (1) the Balkan Peninsula and the Middle East, (2) North America and Europe, (3) North Africa exclusive of Morocco, and (4) the Iberian Peninsula and Morocco. Daucus carota subsp. maximus was discriminated, but neither it, nor subsp. gummifer (defined in a broad sense) are monophyletic. CONCLUSIONS: Our study suggests that (1) the morphotypes identified as D. carota subspecies gummifer (as currently broadly circumscribed), all confined to areas near the Atlantic Ocean and the western Mediterranean Sea, have separate origins from sympatric members of other subspecies of D. carota, (2) D. carota subsp. maximus, on two clades with some accessions of subsp. carota, can be distinguished from each other but only with poor morphological support, (3) D. carota subsp. capillifolius, well distinguished morphologically, is an apospecies relative to North African populations of D. carota subsp. carota, (4) the eastern cultivated carrots have origins closer to wild carrots from central Asia than to western cultivated carrots, and (5) large SNP data sets are suitable for species-level phylogenetic studies in Daucus.


Subject(s)
Daucus carota/genetics , Genotyping Techniques/methods , Sequence Analysis, DNA/methods , Daucus carota/anatomy & histology , Ecotype , Genetic Variation , Genotype , Likelihood Functions , Phylogeny , Polymorphism, Single Nucleotide/genetics , Species Specificity
15.
Nat Genet ; 48(6): 657-66, 2016 06.
Article in English | MEDLINE | ID: mdl-27158781

ABSTRACT

We report a high-quality chromosome-scale assembly and analysis of the carrot (Daucus carota) genome, the first sequenced genome to include a comparative evolutionary analysis among members of the euasterid II clade. We characterized two new polyploidization events, both occurring after the divergence of carrot from members of the Asterales order, clarifying the evolutionary scenario before and after radiation of the two main asterid clades. Large- and small-scale lineage-specific duplications have contributed to the expansion of gene families, including those with roles in flowering time, defense response, flavor, and pigment accumulation. We identified a candidate gene, DCAR_032551, that conditions carotenoid accumulation (Y) in carrot taproot and is coexpressed with several isoprenoid biosynthetic genes. The primary mechanism regulating carotenoid accumulation in carrot taproot is not at the biosynthetic level. We hypothesize that DCAR_032551 regulates upstream photosystem development and functional processes, including photomorphogenesis and root de-etiolation.


Subject(s)
Biological Evolution , Carotenoids/metabolism , Daucus carota/genetics , Genome, Plant , Daucus carota/classification , Daucus carota/metabolism , Genes, Regulator , Genetic Linkage , Genetic Markers , Phylogeny , Plant Roots/metabolism
16.
Front Plant Sci ; 7: 231, 2016.
Article in English | MEDLINE | ID: mdl-26973674

ABSTRACT

The natural history of epiphytic plant species has been extensively studied. However, little is known about the physiology and genetics of epiphytism. This is due to difficulties associated with growing epiphytic plants and the lack of tools for genomics studies and genetic manipulations. In this study, tubers were generated from 223 accessions of 42 wild potato Solanum species, including the epiphytic species S. morelliforme and its sister species S. clarum. Lyophilized samples were analyzed for 12 minerals using inductively coupled plasma optical emission spectrometry. Mineral levels in tubers of S. morelliforme and S. clarum were among the highest for 10 out of the 12 elements evaluated. These two wild potato relatives are native to southern Mexico and Central America and live as epiphytes or in epiphytic-like conditions. We propose the use of S. morelliforme and S. clarum as model organisms for the study of mineral uptake efficiency. They have a short life cycle, can be propagated vegetatively via tubers or cuttings, and can be easily grown in controlled environments. In addition, genome sequence data are available for potato. Transgenic manipulations and somatic fusions will allow the movement of genes from these epiphytes to cultivated potato.

18.
PLoS One ; 10(4): e0122599, 2015.
Article in English | MEDLINE | ID: mdl-25923711

ABSTRACT

Crop wild relatives have a long history of use in potato breeding, particularly for pest and disease resistance, and are expected to be increasingly used in the search for tolerance to biotic and abiotic stresses. Their current and future use in crop improvement depends on their availability in ex situ germplasm collections. As these plants are impacted in the wild by habitat destruction and climate change, actions to ensure their conservation ex situ become ever more urgent. We analyzed the state of ex situ conservation of 73 of the closest wild relatives of potato (Solanum section Petota) with the aim of establishing priorities for further collecting to fill important gaps in germplasm collections. A total of 32 species (43.8%), were assigned high priority for further collecting due to severe gaps in their ex situ collections. Such gaps are most pronounced in the geographic center of diversity of the wild relatives in Peru. A total of 20 and 18 species were assessed as medium and low priority for further collecting, respectively, with only three species determined to be sufficiently represented currently. Priorities for further collecting include: (i) species completely lacking representation in germplasm collections; (ii) other high priority taxa, with geographic emphasis on the center of species diversity; (iii) medium priority species. Such collecting efforts combined with further emphasis on improving ex situ conservation technologies and methods, performing genotypic and phenotypic characterization of wild relative diversity, monitoring wild populations in situ, and making conserved wild relatives and their associated data accessible to the global research community, represent key steps in ensuring the long-term availability of the wild genetic resources of this important crop.


Subject(s)
Crops, Agricultural/physiology , Plant Breeding , Seed Bank , Solanum/physiology , Climate Change , Conservation of Natural Resources , Crops, Agricultural/genetics , Crops, Agricultural/immunology , Disease Resistance , Ecosystem , Genotype , Peru , Solanum/genetics , Solanum/immunology
19.
Article in Spanish | LILACS-Express | LILACS, LIPECS | ID: biblio-1522383

ABSTRACT

SolanumL. es uno de los géneros que posee una alta riqueza de especies dentro de la flora peruana y dentro de los Andes tropicales en general. Presentamos una lista revisada de 276 especies de Solanum para el Perú, de estas 253 son nativas, mientras que 23 son introducidas y/o cultivadas. Un total de 74 especies de Solanum (29% de las especies nativas) son endémicas de Perú. Además 58 especies se encuentran solamente en pequeñas poblaciones fuera del Perú, y estas especies están designadas aquí como casi endémicas para destacar el rol importante del Perú en la futura protección de estas especies. El pico de diversidad de especies es observado entre 2500 - 3000 m de elevación, pero la diversidad de especies endémicas es más alta entre 3000 - 3500 m. Cajamarca tiene el más alto número de especies (130 spp.) y de especies endémicas (29 spp.), incluso si se considera el efecto del área. Centros de diversidad de especies endémicas se localizan en las provincias de Cajamarca (Cajamarca), Huaraz y Carhuaz (Ancash), Canta y Huarochirí (Lima). Centros de endemismos secundarios con una alta concentración tanto de especies endémicas y de casi endémicas se encuentran en San Ignacio y Cutervo (Cajamarca), Santiago de Chuco (La Libertad), Oxapampa (Pasco), y Cusco (Cusco): Los actuales patrones de diversidad están altamente correlacionados con la densidad de colecciones, por lo que es necesario una mayor colecta en todas las regiones, especialmente en Arequipa, Ayacucho, Puno, Ancash, Huánuco, Amazonas y Cajamarca, donde se indican altos niveles de diversidad y endemismo de especies, pero de las cuales existen pocas colecciones.


The genus Solanumis among the most species-rich genera both of the Peruvian flora and of the tropical Andes in general. The present revised checklist treats 276 species of SolanumL., of which 253 are native, while 23 are introduced and/or cultivated. A total of 74 Solanumspecies (29% of native species) are endemic to Peru. Additional 58 species occur only in small number of populations outside Peru, and these species are here labelled as near-endemics to highlight the role Peru playes in their future protection. Species diversity is observed to peak between 2500 - 3000 m elevation, but endemic species diversity is highest between 3000 - 3500 m elevation. Cajamarca has the highest number of endemic (29 spp.) and total species (130 spp.), even when considering the effect of area. Centers of endemic species diversity are observed in provinces of Cajamarca(Cajamarca),Huaraz and Carhuaz (Ancash), and Canta and Huarochirí (Lima). Secondary centres of endemism with high concentrations of both endemics and near-endemics are found in San Ignacio and Cutervo (Cajamarca), Santiago de Chuco (La Libertad), Oxapampa (Pasco), and Cusco (Cusco). Current diversity patterns are highly correlated with collection densities, and further collecting is needed across all areas, especially from Arequipa, Ayacucho, Puno, Ancash, Huánuco, Amazonas and Cajamarca, where high levels of species diversity and endemism are indicated but only a few collections of many species are known.

20.
Am J Bot ; 101(11): 2005-16, 2014 Nov.
Article in English | MEDLINE | ID: mdl-25366864

ABSTRACT

PREMISE OF STUDY: Molecular phylogenetics of genome-scale data sets (phylogenomics) often produces phylogenetic trees with unprecedented resolution. A companion phylogenomics analysis of Daucus using 94 conserved nuclear orthologs supported many of the traditional species but showed unexpected results that require morphological analyses to help interpret them in a practical taxonomic context. METHODS: We evaluated character state distributions, stepwise discriminant analyses, canonical variate analyses, and hierarchical cluster analyses from 40 morphological characters from 81 accessions of 14 taxa of Daucus and eight species in related genera in an experimental plot. KEY RESULTS: Most characters showed tremendous variation with character state overlap across many taxa. Multivariate analyses separated the outgroup taxa easily from the Daucus ingroup. Concordant with molecular analyses, most species form phenetic groups, except the same taxa that are problematical in the molecular results: (1) the subspecies of D. carota, (2) D. sahariensis and D. syrticus, and (3) D. broteri and D. guttatus. CONCLUSIONS: Phenetic analyses, in combination with molecular data, support many Daucus species, but mostly by overlapping ranges of size and meristic variation. The subspecies of D. carota are poorly separated morphologically, are paraphyletic, and all could be recognized at the subspecies rank under D. carota. Daucus sahariensis and D. syrticus are so similar morphologically that they could be placed in synonymy. Combined molecular and morphological data support three species in accessions previously identified as D. broteri and D. guttatus. Molecular and morphological results support the new combination Daucus carota subsp. capillifolius.


Subject(s)
Apiaceae/genetics , Evolution, Molecular , Apiaceae/anatomy & histology , DNA, Plant/chemistry , DNA, Plant/genetics , Phylogeny
SELECTION OF CITATIONS
SEARCH DETAIL