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Prudencio AS, Devin SR, Mahdavi SME, Martínez-García PJ, Salazar JA, Martínez-Gómez P. Spontaneous, Artificial, and Genome Editing-Mediated Mutations in Prunus. Int J Mol Sci 2022; 23:ijms232113273. [PMID: 36362061 PMCID: PMC9653787 DOI: 10.3390/ijms232113273] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Revised: 10/27/2022] [Accepted: 10/28/2022] [Indexed: 11/06/2022] Open
Abstract
Mutation is a source of genetic diversity widely used in breeding programs for the acquisition of agronomically interesting characters in commercial varieties of the Prunus species, as well as in the rest of crop species. Mutation can occur in nature at a very low frequency or can be induced artificially. Spontaneous or bud sport mutations in somatic cells can be vegetatively propagated to get an individual with the mutant phenotype. Unlike animals, plants have unlimited growth and totipotent cells that let somatic mutations to be transmitted to the progeny. On the other hand, in vitro tissue culture makes it possible to induce mutation in plant material and perform large screenings for mutant’s selection and cleaning of chimeras. Finally, targeted mutagenesis has been boosted by the application of CRISPR (Clustered Regularly Interspaced Short Palindromic Repeats)/Cas9 and Transcription activator-like effector nuclease (TALEN) editing technologies. Over the last few decades, environmental stressors such as global warming have been threatening the supply of global demand for food based on population growth in the near future. For this purpose, the release of new varieties adapted to such changes is a requisite, and selected or generated Prunus mutants by properly regulated mechanisms could be helpful to this task. In this work, we reviewed the most relevant mutations for breeding traits in Prunus species such as flowering time, self-compatibility, fruit quality, and disease tolerance, including new molecular perspectives in the present postgenomic era including CRISPR/Cas9 and TALEN editing technologies.
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Affiliation(s)
- Angel S. Prudencio
- Department of Plant Breeding, Centro de Edafología y Biología Apliacada del Segura-Consejo Superior de Investigaciones Científicas (CEBAS-CSIC), 30100 Espinardo, Spain
| | - Sama Rahimi Devin
- Department of Horticultural Science, College of Agriculture, Shiraz University, Shiraz 7144165186, Iran
| | | | - Pedro J. Martínez-García
- Department of Plant Breeding, Centro de Edafología y Biología Apliacada del Segura-Consejo Superior de Investigaciones Científicas (CEBAS-CSIC), 30100 Espinardo, Spain
| | - Juan A. Salazar
- Department of Plant Breeding, Centro de Edafología y Biología Apliacada del Segura-Consejo Superior de Investigaciones Científicas (CEBAS-CSIC), 30100 Espinardo, Spain
| | - Pedro Martínez-Gómez
- Department of Plant Breeding, Centro de Edafología y Biología Apliacada del Segura-Consejo Superior de Investigaciones Científicas (CEBAS-CSIC), 30100 Espinardo, Spain
- Correspondence: ; Tel.: +34-968-396-200
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Lee CY, Lin HJ, Viswanath KK, Lin CP, Chang BCH, Chiu PH, Chiu CT, Wang RH, Chin SW, Chen FC. The development of functional mapping by three sex-related loci on the third whorl of different sex types of Carica papaya L. PLoS One 2018; 13:e0194605. [PMID: 29566053 PMCID: PMC5864051 DOI: 10.1371/journal.pone.0194605] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2017] [Accepted: 03/06/2018] [Indexed: 11/19/2022] Open
Abstract
Carica papaya L. is an important economic crop worldwide and is used as a model plant for sex-determination research. To study the different flower sex types, we screened sex-related genes using alternative splicing sequences (AS-seqs) from a transcriptome database of the three flower sex types, i.e., males, females, and hermaphrodites, established at 28 days before flowering using 15 bacterial artificial chromosomes (BACs) of C. papaya L. After screening, the cDNA regions of the three sex-related loci, including short vegetative phase-like (CpSVPL), the chromatin assembly factor 1 subunit A-like (CpCAF1AL), and the somatic embryogenesis receptor kinase (CpSERK), which contained eight sex-related single-nucleotide polymorphisms (SNPs) from the different sex types of C. papaya L., were genotyped using high-resolution melting (HRM). The three loci were examined regarding the profiles of the third whorl, as described below. CpSVPL, which had one SNP associated with the three sex genotypes, was highly expressed in the male and female sterile flowers (abnormal hermaphrodite flowers) that lacked the fourth whorl structure. CpCAF1AL, which had three SNPs associated with the male genotype, was highly expressed in male and normal hermaphrodite flowers, and had no AS-seqs, whereas it exhibited low expression and an AS-seqs in intron 11 in abnormal hermaphrodite flowers. Conversely, carpellate flowers (abnormal hermaphrodite flowers) showed low expression of CpSVPL and AS-seqs in introns 5, 6, and 7 of CpSERK, which contained four SNPs associated with the female genotype. Specifically, the CpSERK and CpCAF1AL loci exhibited no AS-seq expression in the third whorl of the male and normal hermaphrodite flowers, respectively, and variance in the AS-seq expression of all other types of flowers. Functional mapping of the third whorl of normal hermaphrodites indicated no AS-seq expression in CpSERK, low CpSVPL expression, and, for CpCAF1AL, high expression and no AS-seq expression on XYh-type chromosomes.
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Affiliation(s)
- Chen-Yu Lee
- Department of Plant Industry, National Pingtung University of Science and Technology, Pingtung, Taiwan
- * E-mail: (CYL); (FCC)
| | - Hui-Jun Lin
- Department of Plant Industry, National Pingtung University of Science and Technology, Pingtung, Taiwan
| | - Kotapati Kasi Viswanath
- Department of Plant Industry, National Pingtung University of Science and Technology, Pingtung, Taiwan
| | - Chih-Peng Lin
- Yourgene Bioscience, Shu-Lin District, New Taipei City, Taiwan
| | | | - Pei-Hsun Chiu
- Yourgene Bioscience, Shu-Lin District, New Taipei City, Taiwan
| | - Chan-Tai Chiu
- Pingtung Seed & Seedling Research Center, Taiwan Seed Improvement and Propagation Station, Pingtung, Taiwan
| | - Ren-Huang Wang
- Kaohsiung District Agricultural Research and Extension Station, Council of Agriculture, Pingtung, Taiwan
| | - Shih-Wen Chin
- Department of Plant Industry, National Pingtung University of Science and Technology, Pingtung, Taiwan
| | - Fure-Chyi Chen
- Department of Plant Industry, National Pingtung University of Science and Technology, Pingtung, Taiwan
- * E-mail: (CYL); (FCC)
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Haplotype analysis of the germacrene A synthase gene and association with cynaropicrin content and biological activities in Cynara cardunculus. Mol Genet Genomics 2017; 293:417-433. [PMID: 29143866 DOI: 10.1007/s00438-017-1388-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2017] [Accepted: 10/27/2017] [Indexed: 12/13/2022]
Abstract
Cynara cardunculus: L. represents a natural source of terpenic compounds, with the predominant molecule being cynaropicrin. Cynaropicrin is gaining interest since it has been correlated to anti-hyperlipidaemia, antispasmodic and cytotoxicity activity against leukocyte cancer cells. The objective of this work was to screen a collection of C. cardunculus, from different origins, for new allelic variants in germacrene A synthase (GAS) gene involved in the cynaropicrin biosynthesis and correlate them with improved cynaropicrin content and biological activities. Using high-resolution melting, nine haplotypes were identified. The putative impact of the identified allelic variants in GAS protein was evaluated by bioinformatic tools and polymorphisms that putatively lead to protein conformational changes were described. Additionally, cynaropicrin and main pentacyclic triterpenes contents, and antithrombin, antimicrobial and antiproliferative activities were also determined in C. cardunculus leaf lipophilic-derived extracts. In this work we identified allelic variants with putative impact on GAS protein, which are significantly associated with cynaropicrin content and antiproliferative activity. The results obtained suggest that the identified polymorphisms should be explored as putative genetic markers correlated with biological properties in Cynara cardunculus.
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Ferro AM, Ramos P, Guerreiro O, Jerónimo E, Pires I, Capel C, Capel J, Lozano R, Duarte MF, Oliveira MM, Gonçalves S. Impact of novel SNPs identified in Cynara cardunculus genes on functionality of proteins regulating phenylpropanoid pathway and their association with biological activities. BMC Genomics 2017; 18:183. [PMID: 28212611 PMCID: PMC5314637 DOI: 10.1186/s12864-017-3534-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2016] [Accepted: 02/02/2017] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Cynara cardunculus L. offers a natural source of phenolic compounds with the predominant molecule being chlorogenic acid. Chlorogenic acid is gaining interest due to its involvement in various biological properties such as, antibacterial, antifungal, antioxidant, hepatoprotective, and anticarcinogenic activities. RESULTS In this work we screened a Cynara cardunculus collection for new allelic variants in key genes involved in the chlorogenic acid biosynthesis pathway. The target genes encode p-coumaroyl ester 3'-hydroxylase (C3'H) and hydroxycinnamoyl-CoA: quinate hydroxycinnamoyl transferase (HQT), both participating in the synthesis of chlorogenic acid. Using high-resolution melting, the C3'H gene proved to be highly conserved with only 4 haplotypes while, for HQT, 17 haplotypes were identified de novo. The putative influence of the identified polymorphisms in C3'H and HQT proteins was further evaluated using bioinformatics tools. We could identify some polymorphisms that may lead to protein conformational changes. Chlorogenic acid content, antioxidant and antithrombin activities were also evaluated in Cc leaf extracts and an association analysis was performed to assess a putative correlation between these traits and the identified polymorphisms. CONCLUSION In this work we identified allelic variants with putative impact on C3'H and HQT proteins which are significantly associated with chlorogenic acid content and antioxidant activity. Further study of these alleles should be explored to assess putative relevance as genetic markers correlating with Cynara cardunculus biological properties with further confirmation by functional analysis.
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Affiliation(s)
- Ana Margarida Ferro
- Centro de Biotecnologia Agrícola e Agro-Alimentar do Alentejo (CEBAL), Instituto Politécnico de Beja (IPBeja), Rua Pedro Soares, 7801-908 Beja, Portugal
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa (ITQB NOVA), Av. da República, 2781-901 Oeiras, Portugal
| | - Patrícia Ramos
- Centro de Biotecnologia Agrícola e Agro-Alimentar do Alentejo (CEBAL), Instituto Politécnico de Beja (IPBeja), Rua Pedro Soares, 7801-908 Beja, Portugal
- Centre for Research in Ceramics and Composite Materials (CICECO) and Department of Chemistry, University of Aveiro, 3810-193 Aveiro, Portugal
| | - Olinda Guerreiro
- Centro de Biotecnologia Agrícola e Agro-Alimentar do Alentejo (CEBAL), Instituto Politécnico de Beja (IPBeja), Rua Pedro Soares, 7801-908 Beja, Portugal
- Centro de Investigação Interdisciplinar em Sanidade Animal (CIISA), Faculdade de Medicina Veterinária, University of Lisbon, Avenida da Universidade Técnica, 1300-477 Lisboa, Portugal
| | - Eliana Jerónimo
- Centro de Biotecnologia Agrícola e Agro-Alimentar do Alentejo (CEBAL), Instituto Politécnico de Beja (IPBeja), Rua Pedro Soares, 7801-908 Beja, Portugal
| | - Inês Pires
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa (ITQB NOVA), Av. da República, 2781-901 Oeiras, Portugal
| | - Carmen Capel
- Centro de Investigación en Biotecnología Agroalimentaria (BITAL), Universidad de Almería, 04120 Almeria, Spain
| | - Juan Capel
- Centro de Investigación en Biotecnología Agroalimentaria (BITAL), Universidad de Almería, 04120 Almeria, Spain
| | - Rafael Lozano
- Centro de Investigación en Biotecnología Agroalimentaria (BITAL), Universidad de Almería, 04120 Almeria, Spain
| | - Maria F. Duarte
- Centro de Biotecnologia Agrícola e Agro-Alimentar do Alentejo (CEBAL), Instituto Politécnico de Beja (IPBeja), Rua Pedro Soares, 7801-908 Beja, Portugal
| | - M. Margarida Oliveira
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa (ITQB NOVA), Av. da República, 2781-901 Oeiras, Portugal
| | - Sónia Gonçalves
- Centro de Biotecnologia Agrícola e Agro-Alimentar do Alentejo (CEBAL), Instituto Politécnico de Beja (IPBeja), Rua Pedro Soares, 7801-908 Beja, Portugal
- Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, CB101SA Cambridge, UK
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Ebili HO, Hassall J, Asiri A, Ham-Karim H, Fadhil W, Agboola AJ, Ilyas M. QMC-PCRx: a novel method for rapid mutation detection. J Clin Pathol 2017; 70:702-711. [PMID: 28153952 DOI: 10.1136/jclinpath-2016-204264] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2016] [Revised: 01/09/2017] [Accepted: 01/10/2017] [Indexed: 11/03/2022]
Abstract
AIMS We previously described the quick multiplex consensus PCR (QMC-PCR) as a method for rapid mutation screening in low-quality template. QMC-PCR has two-stages: a prediagnostic multiplex (PDM) reaction followed by a single specific diagnostic reaction with high-resolution melting (HRM) analysis. We aimed to develop QMC-PCRx in which second stage was multiplexed to allow testing of multiple targets. METHODS The PDM reaction was retained without change. For the second stage, in silico design was used to identify targets amenable to a multiplex specific diagnostic reaction and multiplex HRM (mHRM) analysis. Following optimisation, 17 colorectal cancers were tested for mutation in five hotspots. For QMC-PCR, each target was tested individually. For QMC-PCRx, the targets were tested in the following combinations (i) KRAS exon 3/PIK3CA exon 20/PTEN exon 3 in triplex and (ii) PTEN exon 7/NRAS exon 2 in duplex. The degree of agreement between the novel QMC-PCRx and the standard QMC-PCR was tested by the percentage concordance. RESULTS Optimisation of mHRM showed that peaks needed to be separated (without overlap) and the optimal number was three targets per test. Our experimental design produced distinct and widely separated peaks for the individual targets although one of the primers needed a GC-tail. A total of 85 individual targets were tested; this required 85 second-stage PCR/HRM tests by QMC-PCR versus 34 second-stage tests by QMC-PCRx. The percentage concordance between the singleplex and multiplex methodologies was 100%. CONCLUSIONS A multiplexed analysis using HRM is possible without loss of diagnostic accuracy. The novel QMC-PCRx protocol can significantly reduce workload and costs of mutation screening.
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Affiliation(s)
- Henry O Ebili
- Division of Cancer and Stem Cell, Faculty of Medicine & Health Sciences, University of Nottingham, Nottingham, UK.,Department of Morbid Anatomy and Histopathology, Olabisi Onabanjo University, Ago-Iwoye, Nigeria
| | - James Hassall
- Division of Cancer and Stem Cell, Faculty of Medicine & Health Sciences, University of Nottingham, Nottingham, UK
| | - Abutaleb Asiri
- Division of Cancer and Stem Cell, Faculty of Medicine & Health Sciences, University of Nottingham, Nottingham, UK
| | - Hersh Ham-Karim
- Division of Cancer and Stem Cell, Faculty of Medicine & Health Sciences, University of Nottingham, Nottingham, UK
| | - Wakkas Fadhil
- Division of Cancer and Stem Cell, Faculty of Medicine & Health Sciences, University of Nottingham, Nottingham, UK.,Nottingham Molecular Pathology Node, University of Nottingham, Nottingham, UK
| | - Ayodeji Johnson Agboola
- Department of Morbid Anatomy and Histopathology, Olabisi Onabanjo University, Ago-Iwoye, Nigeria
| | - Mohammad Ilyas
- Division of Cancer and Stem Cell, Faculty of Medicine & Health Sciences, University of Nottingham, Nottingham, UK.,Nottingham Molecular Pathology Node, University of Nottingham, Nottingham, UK
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Simko I. High-Resolution DNA Melting Analysis in Plant Research. TRENDS IN PLANT SCIENCE 2016; 21:528-537. [PMID: 26827247 DOI: 10.1016/j.tplants.2016.01.004] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2015] [Revised: 12/05/2015] [Accepted: 01/05/2016] [Indexed: 05/22/2023]
Abstract
Genetic and genomic studies provide valuable insight into the inheritance, structure, organization, and function of genes. The knowledge gained from the analysis of plant genes is beneficial to all aspects of plant research, including crop improvement. New methods and tools are continually being developed to facilitate rapid and accurate mapping, sequencing, and analyzing of genes. Here, I review the recent progress in the application of high-resolution melting (HRM) analysis of DNA, a method that allows detecting polymorphism in double-stranded DNA by comparing profiles of melting curves. Use of HRM has expanded considerably in the past few years as the method was successfully applied for high-throughput genotyping, mapping genes, testing food products and seeds, and other areas of plant research.
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Affiliation(s)
- Ivan Simko
- United States Department of Agriculture, Agricultural Research Service, U.S. Agricultural Research Station, 1636 E. Alisal St, Salinas, CA 93905, USA.
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Acanda Y, Martínez Ó, Prado MJ, González MV, Rey M. EMS mutagenesis and qPCR-HRM prescreening for point mutations in an embryogenic cell suspension of grapevine. PLANT CELL REPORTS 2014; 33:471-481. [PMID: 24362838 DOI: 10.1007/s00299-013-1547-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2013] [Revised: 11/12/2013] [Accepted: 11/25/2013] [Indexed: 06/03/2023]
Abstract
KEY MESSAGE Embryogenic suspension cultures are suitable for EMS mutagenesis in grapevine, and HRM prescreening of EMS-treated somatic embryo clusters allows rapid detection of point mutations before plant regeneration. ABSTRACT Somatic embryogenesis is an excellent system for induced mutagenesis and clonal propagation in woody plants. Our work was focused on establishing a procedure for inducing ethyl methanesulfonate (EMS) mutagenesis in grapevine. Embryogenic cell aggregates (ECAs) growing in liquid medium were treated with increasing concentrations of EMS. We found that EMS dramatically affects the viability of ECAs at concentrations above 20 mM (25.5 ± 2.9 % survival), whereas concentrations above 10 mM affect embryogenic potential (22.1 ± 1.7 % of ECAs gave rise to embryos). Embryo masses generated from EMS-treated embryogenic cell aggregates were prescreened by quantitative PCR-High Resolution Melting (qPCR-HRM) to detect single nucleotide polymorphisms (SNPs) in a 1,000-bp VvNCED1-encoding DNA fragment, which served as the target gene. Detected mutations were verified in regenerated plants by PCR and sequencing. qPCR-HRM analysis of the difference plots for the fluorescence signals allowed detection of a mutation in a sample from an embryogenic aggregate treated with 10 mM EMS. To confirm the nature of the mutation, embryos from this aggregate were recovered and germinated, and leaves were collected for PCR and sequencing analysis. The alignment of sequences from regenerated plants with the wild-type sequence revealed a transitional mutation (G/C to A/T) in the 1,000-bp VvNCED1-encoding region. To our knowledge, this is the first time that EMS mutagenesis has been performed using an embryogenic cell suspension of grapevine.
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Affiliation(s)
- Yosvanis Acanda
- Departamento de Biología Vegetal y Ciencia del Suelo, Universidad de Vigo, Campus Universitario, 36310, Vigo, Spain
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Distefano G, Caruso M, La Malfa S, Gentile A, Wu SB. High resolution melting analysis is a more sensitive and effective alternative to gel-based platforms in analysis of SSR--an example in citrus. PLoS One 2012; 7:e44202. [PMID: 22957003 PMCID: PMC3431301 DOI: 10.1371/journal.pone.0044202] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2012] [Accepted: 07/30/2012] [Indexed: 01/15/2023] Open
Abstract
High resolution melting curve analysis (HRM) has been used as an efficient, accurate and cost-effective tool to detect single nucleotide polymorphisms (SNPs) or insertions or deletions (INDELs). However, its efficiency, accuracy and applicability to discriminate microsatellite polymorphism have not been extensively assessed. The traditional protocols used for SSR genotyping include PCR amplification of the DNA fragment and the separation of the fragments on electrophoresis-based platform. However, post-PCR handling processes are laborious and costly. Furthermore, SNPs present in the sequences flanking repeat motif cannot be detected by polyacrylamide-gel-electrophoresis based methods. In the present study, we compared the discriminating power of HRM with the traditional electrophoresis-based methods and provided a panel of primers for HRM genotyping in Citrus. The results showed that sixteen SSR markers produced distinct polymorphic melting curves among the Citrus spp investigated through HRM analysis. Among those, 10 showed more genotypes by HRM analysis than capillary electrophoresis owing to the presence of SNPs in the amplicons. For the SSR markers without SNPs present in the flanking region, HRM also gave distinct melting curves which detected same genotypes as were shown in capillary electrophoresis (CE) analysis. Moreover, HRM analysis allowed the discrimination of most of the 15 citrus genotypes and the resulting genetic distance analysis clustered them into three main branches. In conclusion, it has been approved that HRM is not only an efficient and cost-effective alternative of electrophoresis-based method for SSR markers, but also a method to uncover more polymorphisms contributed by SNPs present in SSRs. It was therefore suggested that the panel of SSR markers could be used in a variety of applications in the citrus biodiversity and breeding programs using HRM analysis. Furthermore, we speculate that the HRM analysis can be employed to analyse SSR markers in a wide range of applications in all other species.
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Affiliation(s)
- Gaetano Distefano
- Dipartimento di Scienze delle Produzioni Agrarie e Alimentari, University of Catania, Catania, Italy
- School of Environmental and Rural Science, University of New England, Armidale, Australia
| | - Marco Caruso
- Dipartimento di Scienze delle Produzioni Agrarie e Alimentari, University of Catania, Catania, Italy
| | - Stefano La Malfa
- Dipartimento di Scienze delle Produzioni Agrarie e Alimentari, University of Catania, Catania, Italy
| | - Alessandra Gentile
- Dipartimento di Scienze delle Produzioni Agrarie e Alimentari, University of Catania, Catania, Italy
- * E-mail: (S-BW); (AG)
| | - Shu-Biao Wu
- School of Environmental and Rural Science, University of New England, Armidale, Australia
- * E-mail: (S-BW); (AG)
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Castellanos-Rizaldos E, Liu P, Milbury CA, Guha M, Brisci A, Cremonesi L, Ferrari M, Mamon H, Makrigiorgos GM. Temperature-tolerant COLD-PCR reduces temperature stringency and enables robust mutation enrichment. Clin Chem 2012; 58:1130-8. [PMID: 22587896 DOI: 10.1373/clinchem.2012.183095] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
BACKGROUND Low-level mutations in clinical tumor samples often reside below mutation detection limits, thus leading to false negatives that may impact clinical diagnosis and patient management. COLD-PCR (coamplification at lower denaturation temperature PCR) is a technology that magnifies unknown mutations during PCR, thus enabling downstream mutation detection. However, a practical difficulty in applying COLD-PCR has been the requirement for strict control of the denaturation temperature for a given sequence, to within ±0.3 °C. This requirement precludes simultaneous mutation enrichment in sequences of substantially different melting temperature (T(m)) and limits the technique to a single sequence at a time. We present a temperature-tolerant (TT) approach (TT-COLD-PCR) that reduces this obstacle. METHODS We describe thermocycling programs featuring a gradual increase of the denaturation temperature during COLD-PCR. This approach enabled enrichment of mutations when the cycling achieves the appropriate critical denaturation temperature of each DNA amplicon that is being amplified. Validation was provided for KRAS (v-Ki-ras2 Kirsten rat sarcoma viral oncogene homolog) and TP53 (tumor protein p53) exons 6-9 by use of dilutions of mutated DNA, clinical cancer samples, and plasma-circulating DNA. RESULTS A single thermocycling program with a denaturation-temperature window of 2.5-3.0 °C enriches mutations in all DNA amplicons simultaneously, despite their different T(m)s. Mutation enrichments of 6-9-fold were obtained with TT-full-COLD-PCR. Higher mutation enrichments were obtained for the other 2 forms of COLD-PCR, fast-COLD-PCR, and ice-COLD-PCR. CONCLUSIONS Low-level mutations in diverse amplicons with different T(m)s can be mutation enriched via TT-COLD-PCR provided that their T(m)s fall within the denaturation-temperature window applied during amplification. This approach enables simultaneous enrichment of mutations in several amplicons and increases significantly the versatility of COLD-PCR.
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Affiliation(s)
- E Castellanos-Rizaldos
- Division of DNA Repair and Genome Stability, Department of Radiation Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA, USA
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