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1.
Proc Natl Acad Sci U S A ; 121(28): e2400737121, 2024 Jul 09.
Artículo en Inglés | MEDLINE | ID: mdl-38968127

RESUMEN

In recent years, the exploration of genome three-dimensional (3D) conformation has yielded profound insights into the regulation of gene expression and cellular functions in both animals and plants. While animals exhibit a characteristic genome topology defined by topologically associating domains (TADs), plants display similar features with a more diverse conformation across species. Employing advanced high-throughput sequencing and microscopy techniques, we investigated the landscape of 26 histone modifications and RNA polymerase II distribution in tomato (Solanum lycopersicum). Our study unveiled a rich and nuanced epigenetic landscape, shedding light on distinct chromatin states associated with heterochromatin formation and gene silencing. Moreover, we elucidated the intricate interplay between these chromatin states and the overall topology of the genome. Employing a genetic approach, we delved into the role of the histone modification H3K9ac in genome topology. Notably, our investigation revealed that the ectopic deposition of this chromatin mark triggered a reorganization of the 3D chromatin structure, defining different TAD-like borders. Our work emphasizes the critical role of H3K9ac in shaping the topology of the tomato genome, providing valuable insights into the epigenetic landscape of this agriculturally significant crop species.


Asunto(s)
Epigenoma , Histonas , Solanum lycopersicum , Solanum lycopersicum/genética , Solanum lycopersicum/metabolismo , Histonas/metabolismo , Histonas/genética , Epigénesis Genética , Genoma de Planta , Cromatina/metabolismo , Cromatina/genética , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Regulación de la Expresión Génica de las Plantas , Heterocromatina/metabolismo , Heterocromatina/genética , Código de Histonas/genética
2.
Nucleic Acids Res ; 52(6): 3469-3482, 2024 Apr 12.
Artículo en Inglés | MEDLINE | ID: mdl-38421613

RESUMEN

Gene-editing technologies have revolutionized biotechnology, but current gene editors suffer from several limitations. Here, we harnessed the power of gamma-modified peptide nucleic acids (γPNAs) to facilitate targeted, specific DNA invasion and used T7 endonuclease I (T7EI) to recognize and cleave the γPNA-invaded DNA. Our data show that T7EI can specifically target PNA-invaded linear and circular DNA to introduce double-strand breaks (DSBs). Our PNA-Guided T7EI (PG-T7EI) technology demonstrates that T7EI can be used as a programmable nuclease capable of generating single or multiple specific DSBs in vitro under a broad range of conditions and could be potentially applied for large-scale genomic manipulation. With no protospacer adjacent motif (PAM) constraints and featuring a compact protein size, our PG-T7EI system will facilitate and expand DNA manipulations both in vitro and in vivo, including cloning, large-fragment DNA assembly, and gene editing, with exciting applications in biotechnology, medicine, agriculture, and synthetic biology.


Asunto(s)
Roturas del ADN de Doble Cadena , Desoxirribonucleasa I , Ácidos Nucleicos de Péptidos , Desoxirribonucleasa I/metabolismo , ADN/genética , ADN/metabolismo , ADN Circular , Edición Génica
3.
Nucleic Acids Res ; 52(17): 10220-10234, 2024 Sep 23.
Artículo en Inglés | MEDLINE | ID: mdl-39149894

RESUMEN

The 3D chromatin organization plays a major role in the control of gene expression. However, our comprehension of the governing principles behind nuclear organization remains incomplete. Particularly, the spatial segregation of loci with similar repressive transcriptional states in plants poses a significant yet poorly understood puzzle. In this study, employing a combination of genetics and advanced 3D genomics approaches, we demonstrated that a redistribution of facultative heterochromatin marks in regions usually occupied by constitutive heterochromatin marks disrupts the 3D genome compartmentalisation. This disturbance, in turn, triggers novel chromatin interactions between genic and transposable element (TE) regions. Interestingly, our results imply that epigenetic features, constrained by genetic factors, intricately mold the landscape of 3D genome organisation. This study sheds light on the profound genetic-epigenetic interplay that underlies the regulation of gene expression within the intricate framework of the 3D genome. Our findings highlight the complexity of the relationships between genetic determinants and epigenetic features in shaping the dynamic configuration of the 3D genome.


Asunto(s)
Arabidopsis , Elementos Transponibles de ADN , Epigénesis Genética , Genoma de Planta , Heterocromatina , Elementos Transponibles de ADN/genética , Heterocromatina/metabolismo , Heterocromatina/genética , Arabidopsis/genética , Arabidopsis/metabolismo , Regulación de la Expresión Génica de las Plantas , Cromatina/metabolismo , Cromatina/genética , Histonas/metabolismo , Histonas/genética , Genómica/métodos
4.
J Biol Chem ; 300(9): 107720, 2024 Aug 28.
Artículo en Inglés | MEDLINE | ID: mdl-39214308

RESUMEN

Site-specific nucleases are crucial for genome engineering applications in medicine and agriculture. The ideal site-specific nucleases are easily reprogrammable, highly specific in target site recognition, and robust in nuclease activities. Prokaryotic Argonaute (pAgo) proteins have received much attention as biotechnological tools due to their ability to recognize specific target sequences without a protospacer adjacent motif, but their lack of intrinsic dsDNA unwinding activity limits their utility in key applications such as gene editing. Recently, we developed a pAgo-based system for site-specific DNA cleavage at physiological temperatures independently of the DNA form, using peptide nucleic acids (PNAs) to facilitate unwinding dsDNA targets. Here, we fused catalytically dead pAgos with the nuclease domain of the restriction endonuclease FokI and named this modified platform PNA-assisted FokI-(d)pAgo (PNFP) editors. In the PNFP system, catalytically inactive pAgo recognizes and binds to a specific target DNA sequence based on a programmable guide DNA sequence; upon binding to the target site, the FokI domains dimerize and introduce precise dsDNA breaks. We explored key parameters of the PNFP system including the requirements of PNA and guide DNAs, the specificity of PNA and guide DNA on target cleavage, the optimal concentration of different components, reaction time for invasion and cleavage, and ideal temperature and reaction buffer, to ensure efficient DNA editing in vitro. The results demonstrated robust site-specific target cleavage by PNFP system at optimal conditions in vitro. We envision that the PNFP system will provide higher editing efficiency and specificity with fewer off-target effects in vivo.

5.
Nucleic Acids Res ; 51(17): 9491-9506, 2023 09 22.
Artículo en Inglés | MEDLINE | ID: mdl-37560931

RESUMEN

Programmable site-specific nucleases promise to unlock myriad applications in basic biology research, biotechnology and gene therapy. Gene-editing systems have revolutionized our ability to engineer genomes across diverse eukaryotic species. However, key challenges, including delivery, specificity and targeting organellar genomes, pose barriers to translational applications. Here, we use peptide nucleic acids (PNAs) to facilitate precise DNA strand invasion and unwinding, enabling prokaryotic Argonaute (pAgo) proteins to specifically bind displaced single-stranded DNA and introduce site-specific double-strand breaks (DSBs) independent of the target sequence. We named this technology PNA-assisted pAgo editing (PNP editing) and determined key parameters for designing PNP editors to efficiently generate programable site-specific DSBs. Our design allows the simultaneous use of multiple PNP editors to generate multiple site-specific DSBs, thereby informing design considerations for potential in vitro and in vivo applications, including genome editing.


Asunto(s)
Roturas del ADN de Doble Cadena , Edición Génica , Ácidos Nucleicos de Péptidos , Sistemas CRISPR-Cas , ADN/genética , Edición Génica/métodos , Genoma , Ácidos Nucleicos de Péptidos/metabolismo , Proteínas Argonautas/metabolismo
6.
Proc Natl Acad Sci U S A ; 119(28): e2118260119, 2022 07 12.
Artículo en Inglés | MEDLINE | ID: mdl-35763567

RESUMEN

Type VI CRISPR-Cas systems have been repurposed for various applications such as gene knockdown, viral interference, and diagnostics. However, the identification and characterization of thermophilic orthologs will expand and unlock the potential of diverse biotechnological applications. Herein, we identified and characterized a thermostable ortholog of the Cas13a family from the thermophilic organism Thermoclostridium caenicola (TccCas13a). We show that TccCas13a has a close phylogenetic relation to the HheCas13a ortholog from the thermophilic bacterium Herbinix hemicellulosilytica and shares several properties such as thermostability and inability to process its own pre-CRISPR RNA. We demonstrate that TccCas13a possesses robust cis and trans activities at a broad temperature range of 37 to 70 °C, compared with HheCas13a, which has a more limited range and lower activity. We harnessed TccCas13a thermostability to develop a sensitive, robust, rapid, and one-pot assay, named OPTIMA-dx, for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) detection. OPTIMA-dx exhibits no cross-reactivity with other viruses and a limit of detection of 10 copies/µL when using a synthetic SARS-CoV-2 genome. We used OPTIMA-dx for SARS-CoV-2 detection in clinical samples, and our assay showed 95% sensitivity and 100% specificity compared with qRT-PCR. Furthermore, we demonstrated that OPTIMA-dx is suitable for multiplexed detection and is compatible with the quick extraction protocol. OPTIMA-dx exhibits critical features that enable its use at point of care (POC). Therefore, we developed a mobile phone application to facilitate OPTIMA-dx data collection and sharing of patient sample results. This work demonstrates the power of CRISPR-Cas13 thermostable enzymes in enabling key applications in one-pot POC diagnostics and potentially in transcriptome engineering, editing, and therapies.


Asunto(s)
Proteínas Bacterianas , COVID-19 , Proteínas Asociadas a CRISPR , Clostridiales , Endodesoxirribonucleasas , Pruebas en el Punto de Atención , SARS-CoV-2 , Proteínas Bacterianas/química , Proteínas Bacterianas/clasificación , Proteínas Bacterianas/genética , Biotecnología , COVID-19/diagnóstico , Proteínas Asociadas a CRISPR/química , Proteínas Asociadas a CRISPR/clasificación , Proteínas Asociadas a CRISPR/genética , Clostridiales/enzimología , Endodesoxirribonucleasas/química , Endodesoxirribonucleasas/clasificación , Endodesoxirribonucleasas/genética , Estabilidad de Enzimas , Calor , Humanos , Filogenia , SARS-CoV-2/aislamiento & purificación
7.
Anal Chem ; 96(6): 2599-2609, 2024 02 13.
Artículo en Inglés | MEDLINE | ID: mdl-38300270

RESUMEN

Programmable site-specific nucleases (SSNs) hold extraordinary promise to unlock myriad gene editing applications in medicine and agriculture. However, developing small and specific SSNs is needed to overcome the delivery and specificity translational challenges of current genome engineering technologies. Structure-guided nucleases have been harnessed to generate double-strand DNA breaks but with limited success and translational potential. Here, we harnessed the power of peptide nucleic acids (PNAs) for site-specific DNA invasion and the generation of localized DNA structures that are recognized and cleaved by the eukaryotic resolvase AtMOC1 from Arabidopsis thaliana. We named this technology PNA-assisted Resolvase-mediated (PNR) editing. We tested the PNR editing concept in vitro and demonstrated its precise target specificity, examined the nucleotide requirement around the PNA invasion for the AtMOC1-mediated cleavage, mapped the AtMOC1-mediated cleavage sites, tested the role of different types and lengths of PNA molecules invasion into dsDNA for the AtMOC1-mediated cleavage, optimized the in vitro PNA invasion and AtMOC1 cleavage conditions such as temperature, buffer conditions, and cleavage time points, and demonstrated the multiplex cleavage for precise fragment release. We discuss the best design parameters for efficient, site-specific in vitro cleavage using PNR editors.


Asunto(s)
Ácidos Nucleicos de Péptidos , Ácidos Nucleicos de Péptidos/química , Roturas del ADN de Doble Cadena , ADN/química , Edición Génica , Temperatura
8.
Genome Res ; 31(7): 1230-1244, 2021 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-34083408

RESUMEN

In animals, distant H3K27me3-marked Polycomb targets can establish physical interactions forming repressive chromatin hubs. In plants, growing evidence suggests that H3K27me3 acts directly or indirectly to regulate chromatin interactions, although how this histone modification modulates 3D chromatin architecture remains elusive. To decipher the impact of the dynamic deposition of H3K27me3 on the Arabidopsis thaliana nuclear interactome, we combined genetics, transcriptomics, and several 3D epigenomic approaches. By analyzing mutants defective for histone H3K27 methylation or demethylation, we uncovered the crucial role of this chromatin mark in short- and previously unnoticed long-range chromatin loop formation. We found that a reduction in H3K27me3 levels led to a decrease in the interactions within Polycomb-associated repressive domains. Regions with lower H3K27me3 levels in the H3K27 methyltransferase clf mutant established new interactions with regions marked with H3K9ac, a histone modification associated with active transcription, indicating that a reduction in H3K27me3 levels induces a global reconfiguration of chromatin architecture. Altogether, our results reveal that the 3D genome organization is tightly linked to reversible histone modifications that govern chromatin interactions. Consequently, nuclear organization dynamics shapes the transcriptional reprogramming during plant development and places H3K27me3 as a key feature in the coregulation of distant genes.

9.
Plant Biotechnol J ; 22(8): 2282-2300, 2024 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-38685599

RESUMEN

Antimicrobial peptides (AMPs) are emerging as next-generation therapeutics due to their broad-spectrum activity against drug-resistant bacterial strains and their ability to eradicate biofilms, modulate immune responses, exert anti-inflammatory effects and improve disease management. They are produced through solid-phase peptide synthesis or in bacterial or yeast cells. Molecular farming, i.e. the production of biologics in plants, offers a low-cost, non-toxic, scalable and simple alternative platform to produce AMPs at a sustainable cost. In this review, we discuss the advantages of molecular farming for producing clinical-grade AMPs, advances in expression and purification systems and the cost advantage for industrial-scale production. We further review how 'green' production is filling the sustainability gap, streamlining patent and regulatory approvals and enabling successful clinical translations that demonstrate the future potential of AMPs produced by molecular farming. Finally, we discuss the regulatory challenges that need to be addressed to fully realize the potential of molecular farming-based AMP production for therapeutics.


Asunto(s)
Péptidos Antimicrobianos , Agricultura Molecular , Péptidos Antimicrobianos/genética , Péptidos Antimicrobianos/metabolismo , Agricultura Molecular/métodos
10.
Plant Biotechnol J ; 2024 Sep 12.
Artículo en Inglés | MEDLINE | ID: mdl-39264967

RESUMEN

Plants offer a promising chassis for the large-scale, cost-effective production of diverse therapeutics, including antimicrobial peptides (AMPs). However, key advances will reduce production costs, including simplifying the downstream processing and purification steps. Here, using Nicotiana benthamiana plants, we present an improved modular design that enables AMPs to be secreted via the endomembrane system and sequestered in an extracellular compartment, the apoplast. Additionally, we translationally fused an AMP to a mutated small ubiquitin-like modifier sequence, thereby enhancing peptide yield and solubilizing the peptide with minimal aggregation and reduced occurrence of necrotic lesions in the plant. This strategy resulted in substantial peptide accumulation, reaching around 2.9 mg AMP per 20 g fresh weight of leaf tissue. Furthermore, the purified AMP demonstrated low collateral toxicity in primary human skin cells, killed pathogenic bacteria by permeabilizing the membrane and exhibited anti-infective efficacy in a preclinical mouse (Mus musculus) model system, reducing bacterial loads by up to three orders of magnitude. A base-case techno-economic analysis demonstrated the economic advantages and scalability of our plant-based platform. We envision that our work can establish plants as efficient bioreactors for producing preclinical-grade AMPs at a commercial scale, with the potential for clinical applications.

11.
J Exp Bot ; 75(3): 802-818, 2024 Feb 02.
Artículo en Inglés | MEDLINE | ID: mdl-37924151

RESUMEN

Plants employ sophisticated molecular machinery to fine-tune their responses to growth, developmental, and stress cues. Gene expression influences plant cellular responses through regulatory processes such as transcription and splicing. Pre-mRNA is alternatively spliced to increase the genome coding potential and further regulate expression. Serine/arginine-rich (SR) proteins, a family of pre-mRNA splicing factors, recognize splicing cis-elements and regulate both constitutive and alternative splicing. Several studies have reported SR protein genes in the rice genome, subdivided into six subfamilies based on their domain structures. Here, we identified a new splicing factor in rice with an RNA recognition motif (RRM) and SR-dipeptides, which is related to the SR proteins, subfamily SC. OsSCR106 regulates pre-mRNA splicing under abiotic stress conditions. It localizes to the nuclear speckles, a major site for pre-mRNA splicing in the cell. The loss-of-function scr106 mutant is hypersensitive to salt, abscisic acid, and low-temperature stress, and harbors a developmental abnormality indicated by the shorter length of the shoot and root. The hypersensitivity to stress phenotype was rescued by complementation using OsSCR106 fused behind its endogenous promoter. Global gene expression and genome-wide splicing analysis in wild-type and scr106 seedlings revealed that OsSCR106 regulates its targets, presumably through regulating the alternative 3'-splice site. Under salt stress conditions, we identified multiple splice isoforms regulated by OsSCR106. Collectively, our results suggest that OsSCR106 is an important splicing factor that plays a crucial role in accurate pre-mRNA splicing and regulates abiotic stress responses in plants.


Asunto(s)
Oryza , Oryza/genética , Oryza/metabolismo , Precursores del ARN/genética , Precursores del ARN/metabolismo , Factores de Empalme de ARN/genética , Factores de Empalme de ARN/metabolismo , Empalme del ARN , Empalme Alternativo , Plantas/metabolismo , Estrés Fisiológico/genética
12.
Plant Cell Rep ; 43(4): 98, 2024 Mar 18.
Artículo en Inglés | MEDLINE | ID: mdl-38494539

RESUMEN

Genome-editing technologies have revolutionized research in plant biology, with major implications for agriculture and worldwide food security, particularly in the face of challenges such as climate change and increasing human populations. Among these technologies, clustered regularly interspaced short palindromic repeats [CRISPR]-CRISPR-associated protein [Cas] systems are now widely used for editing crop plant genomes. In this review, we provide an overview of CRISPR-Cas technology and its most significant applications for improving crop sustainability. We also review current and potential technological advances that will aid in the future breeding of crops to enhance food security worldwide. Finally, we discuss the obstacles and challenges that must be overcome to realize the maximum potential of genome-editing technologies for future crop and food production.


Asunto(s)
Sistemas CRISPR-Cas , Edición Génica , Humanos , Sistemas CRISPR-Cas/genética , Fitomejoramiento , Productos Agrícolas/genética , Genoma de Planta/genética , Bioingeniería , Agricultura
13.
Anal Chem ; 95(38): 14209-14218, 2023 09 26.
Artículo en Inglés | MEDLINE | ID: mdl-37696750

RESUMEN

Monitoring diseases caused by pathogens or by mutations in DNA sequences requires accurate, rapid, and sensitive tools to detect specific nucleic acid sequences. Here, we describe a new peptide nucleic acid (PNA)-based nucleic acid detection toolkit, termed PNA-powered diagnostics (PNA-Pdx). PNA-Pdx employs PNA probes that bind specifically to a target and are then detected in lateral flow assays. This can precisely detect a specific pathogen or genotype genomic sequence. PNA probes can also be designed to invade double-stranded DNAs (dsDNAs) to produce single-stranded DNAs for precise CRISPR-Cas12b-based detection of genomic SNPs without requiring the protospacer-adjacent motif (PAM), as Cas12b requires PAM sequences only for dsDNA targets. PNA-Pdx identified target nucleic acid sequences at concentrations as low as 2 copies/µL and precisely detected the SARS-CoV-2 genome in clinical samples in 40 min. Furthermore, the specific dsDNA invasion by the PNA coupled with CRISPR-Cas12b precisely detected genomic SNPs without PAM restriction. Overall, PNA-Pdx provides a novel toolkit for nucleic acid and SNP detection as well as highlights the benefits of engineering PNA probes for detecting nucleic acids.


Asunto(s)
COVID-19 , Ácidos Nucleicos , Ácidos Nucleicos de Péptidos , Humanos , Ácidos Nucleicos de Péptidos/genética , Polimorfismo de Nucleótido Simple , SARS-CoV-2 , Péptidos
14.
Int J Mol Sci ; 24(4)2023 Feb 10.
Artículo en Inglés | MEDLINE | ID: mdl-36834960

RESUMEN

Bevacizumab (Bev) a humanized monoclonal antibody that fights vascular endothelial growth factor A (VEGF-A). It was the first specifically considered angiogenesis inhibitor and it has now become the normative first-line therapy for advanced non-small-cell lung cancer (NSCLC). In the current study, polyphenolic compounds were isolated from bee pollen (PCIBP) and encapsulated (EPCIBP) inside moieties of hybrid peptide-protein hydrogel nanoparticles in which bovine serum albumin (BSA) was combined with protamine-free sulfate and targeted with folic acid (FA). The apoptotic effects of PCIBP and its encapsulation (EPCIBP) were further investigated using A549 and MCF-7 cell lines, providing significant upregulation of Bax and caspase 3 genes and downregulation of Bcl2, HRAS, and MAPK as well. This effect was synergistically improved in combination with Bev. Our findings may contribute to the use of EPCIBP simultaneously with chemotherapy to strengthen the effectiveness and minimize the required dose.


Asunto(s)
Antineoplásicos , Bevacizumab , Productos Biológicos , Carcinoma de Pulmón de Células no Pequeñas , Hidrogeles , Animales , Humanos , Células A549/efectos de los fármacos , Células A549/metabolismo , Inhibidores de la Angiogénesis/uso terapéutico , Antineoplásicos/química , Antineoplásicos/farmacología , Abejas/química , Abejas/metabolismo , Bevacizumab/uso terapéutico , Productos Biológicos/química , Productos Biológicos/uso terapéutico , Carcinoma de Pulmón de Células no Pequeñas/tratamiento farmacológico , Carcinoma de Pulmón de Células no Pequeñas/metabolismo , Hidrogeles/química , Hidrogeles/uso terapéutico , Neoplasias Pulmonares/tratamiento farmacológico , Neoplasias Pulmonares/metabolismo , Células MCF-7/efectos de los fármacos , Células MCF-7/metabolismo , Nanopartículas/química , Nanopartículas/uso terapéutico , Polen/química , Polen/metabolismo , Factor A de Crecimiento Endotelial Vascular/uso terapéutico
15.
Anal Chem ; 94(11): 4617-4626, 2022 03 22.
Artículo en Inglés | MEDLINE | ID: mdl-35266687

RESUMEN

Cell-free biosensors can detect various molecules, thus promising to transform the landscape of diagnostics. Here, we developed a simple, rapid, sensitive, and field-deployable small-molecule detection platform based on allosteric transcription factor (aTF)-regulated expression of a clustered regularly interspaced short palindromic repeats (CRISPR) array coupled to Cas12a activity. To this end, we engineered an expression cassette harboring a T7 promoter, an aTF binding sequence, a Cas12a CRISPR array, and protospacer adjacent motif-flanked Cas12a target sequences. In the presence of the ligand, dissociation of the aTF allows transcription of the CRISPR array; this leads to activation of Cas12a collateral activity, which cleaves a single-stranded DNA linker to free a quenched fluorophore, resulting in a rapid, significant increase of fluorescence. As a proof of concept, we used TetR as the aTF to detect different tetracycline antibiotics with high sensitivity and specificity and a simple, hand-held visualizer to develop a fluorescence-based visual readout. We also adapted a mobile phone application to further simplify the interpretation of the results. Finally, we showed that the reagents could be lyophilized to facilitate storage and distribution. This detection platform represents a valuable addition to the toolbox of cell-free, CRISPR-based biosensors, with great potential for in-field deployment to detect non-nucleic acid small molecules.


Asunto(s)
Técnicas Biosensibles , Sistemas CRISPR-Cas , Regulación Alostérica , Técnicas Biosensibles/métodos , Sistemas CRISPR-Cas/genética , Repeticiones Palindrómicas Cortas Agrupadas y Regularmente Espaciadas/genética , ADN de Cadena Simple
16.
Plant Biotechnol J ; 20(10): 1859-1873, 2022 10.
Artículo en Inglés | MEDLINE | ID: mdl-35689490

RESUMEN

Plant diseases caused by viruses limit crop production and quality, resulting in significant losses. However, options for managing viruses are limited; for example, as systemic obligate parasites, they cannot be killed by chemicals. Sensitive, robust, affordable diagnostic assays are needed to detect the presence of viruses in plant materials such as seeds, vegetative parts, insect vectors, or alternative hosts and then prevent or limit their introduction into the field by destroying infected plant materials or controlling insect hosts. Diagnostics based on biological and physical properties are not very sensitive and are time-consuming, but assays based on viral proteins and nucleic acids are more specific, sensitive, and rapid. However, most such assays require laboratories with sophisticated equipment and technical skills. By contrast, isothermal-based assays such as loop-mediated isothermal amplification (LAMP) and recombinase polymerase amplification (RPA) are simple, easy to perform, reliable, specific, and rapid and do not require specialized equipment or skills. Isothermal amplification assays can be performed using lateral flow devices, making them suitable for onsite detection or testing in the field. To overcome non-specific amplification and cross-contamination issues, isothermal amplification assays can be coupled with CRISPR/Cas technology. Indeed, the collateral activity associated with some CRISPR/Cas systems has been successfully harnessed for visual detection of plant viruses. Here, we briefly describe traditional methods for detecting viruses and then examine the various isothermal assays that are being harnessed to detect viruses.


Asunto(s)
Ácidos Nucleicos , Virus de Plantas , Virus de Plantas/genética , Recombinasas , Sensibilidad y Especificidad , Proteínas Virales
17.
Plant Biotechnol J ; 20(12): 2418-2429, 2022 12.
Artículo en Inglés | MEDLINE | ID: mdl-36072993

RESUMEN

Efficient pathogen diagnostics and genotyping methods enable effective disease management and breeding, improve crop productivity and ensure food security. However, current germplasm selection and pathogen detection techniques are laborious, time-consuming, expensive and not easy to mass-scale application in the field. Here, we optimized a field-deployable lateral flow assay, Bio-SCAN, as a highly sensitive tool to precisely identify elite germplasm and detect mutations, transgenes and phytopathogens in <1 h, starting from sample isolation to result output using lateral flow strips. As a proof of concept, we genotyped various wheat germplasms for the Lr34 and Lr67 alleles conferring broad-spectrum resistance to stripe rust, confirmed the presence of synthetically produced herbicide-resistant alleles in the rice genome and screened for the presence of transgenic elements in the genome of transgenic tobacco and rice plants with 100% specificity. We also successfully applied this new assay to the detection of phytopathogens, including viruses and bacterial pathogens in Nicotiana benthamiana, and two destructive fungal pathogens (Puccinia striiformis f. sp. tritici and Magnaporthe oryzae Triticum) in wheat. Our results illustrate the power of Bio-SCAN in crop breeding, genetic engineering and pathogen diagnostics to enhance food security. The high sensitivity, simplicity, versatility and in-field deployability make the Bio-SCAN as an attractive molecular diagnostic tool for diverse applications in agriculture.


Asunto(s)
Basidiomycota , Oryza , Genotipo , Fitomejoramiento , Nicotiana , Triticum/genética , Agricultura , Oryza/genética , Enfermedades de las Plantas/genética , Resistencia a la Enfermedad/genética
18.
Plant Physiol ; 186(4): 1770-1785, 2021 08 03.
Artículo en Inglés | MEDLINE | ID: mdl-35237805

RESUMEN

Molecular engineering of plant immunity to confer resistance against plant viruses holds great promise for mitigating crop losses and improving plant productivity and yields, thereby enhancing food security. Several approaches have been employed to boost immunity in plants by interfering with the transmission or lifecycles of viruses. In this review, we discuss the successful application of clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein (Cas) (CRISPR/Cas) systems to engineer plant immunity, increase plant resistance to viruses, and develop viral diagnostic tools. Furthermore, we examine the use of plant viruses as delivery systems to engineer virus resistance in plants and provide insight into the limitations of current CRISPR/Cas approaches and the potential of newly discovered CRISPR/Cas systems to engineer better immunity and develop better diagnostics tools for plant viruses. Finally, we outline potential solutions to key challenges in the field to enable the practical use of these systems for crop protection and viral diagnostics.


Asunto(s)
Sistemas CRISPR-Cas , Resistencia a la Enfermedad/genética , Fitomejoramiento/métodos , Enfermedades de las Plantas/genética , Enfermedades de las Plantas/virología , Inmunidad de la Planta/genética , Virus de Plantas/patogenicidad , Productos Agrícolas/genética , Productos Agrícolas/virología , Edición Génica/métodos
19.
Nucleic Acids Res ; 48(11): 5953-5966, 2020 06 19.
Artículo en Inglés | MEDLINE | ID: mdl-32396165

RESUMEN

The modification of histones by acetyl groups has a key role in the regulation of chromatin structure and transcription. The Arabidopsis thaliana histone acetyltransferase GCN5 regulates histone modifications as part of the Spt-Ada-Gcn5 Acetyltransferase (SAGA) transcriptional coactivator complex. GCN5 was previously shown to acetylate lysine 14 of histone 3 (H3K14ac) in the promoter regions of its target genes even though GCN5 binding did not systematically correlate with gene activation. Here, we explored the mechanism through which GCN5 controls transcription. First, we fine-mapped its GCN5 binding sites genome-wide and then used several global methodologies (ATAC-seq, ChIP-seq and RNA-seq) to assess the effect of GCN5 loss-of-function on the expression and epigenetic regulation of its target genes. These analyses provided evidence that GCN5 has a dual role in the regulation of H3K14ac levels in their 5' and 3' ends of its target genes. While the gcn5 mutation led to a genome-wide decrease of H3K14ac in the 5' end of the GCN5 down-regulated targets, it also led to an increase of H3K14ac in the 3' ends of GCN5 up-regulated targets. Furthermore, genome-wide changes in H3K14ac levels in the gcn5 mutant correlated with changes in H3K9ac at both 5' and 3' ends, providing evidence for a molecular link between the depositions of these two histone modifications. To understand the biological relevance of these regulations, we showed that GCN5 participates in the responses to biotic stress by repressing salicylic acid (SA) accumulation and SA-mediated immunity, highlighting the role of this protein in the regulation of the crosstalk between diverse developmental and stress-responsive physiological programs. Hence, our results demonstrate that GCN5, through the modulation of H3K14ac levels on its targets, controls the balance between biotic and abiotic stress responses and is a master regulator of plant-environmental interactions.


Asunto(s)
Proteínas de Arabidopsis/metabolismo , Arabidopsis/genética , Regulación de la Expresión Génica de las Plantas , Genes de Plantas/genética , Histona Acetiltransferasas/metabolismo , Histonas/metabolismo , Homeostasis , Lisina/metabolismo , Ácido Salicílico/metabolismo , Regiones no Traducidas 5'/genética , Acetilación , Arabidopsis/inmunología , Histonas/química , Lisina/química , Inmunidad de la Planta/genética , Regiones Promotoras Genéticas/genética , Transcripción Genética
20.
Nano Lett ; 21(8): 3596-3603, 2021 04 28.
Artículo en Inglés | MEDLINE | ID: mdl-33844549

RESUMEN

Rapid, sensitive, and specific point-of-care testing for pathogens is crucial for disease control. Lateral flow assays (LFAs) have been employed for nucleic acid detection, but they have limited sensitivity and specificity. Here, we used a fusion of catalytically inactive SpCas9 endonuclease and VirD2 relaxase for sensitive, specific nucleic acid detection by LFA. In this assay, the target nucleic acid is amplified with biotinylated oligos. VirD2-dCas9 specifically binds the target sequence via dCas9 and covalently binds to a FAM-tagged oligonucleotide via VirD2. The biotin label and FAM tag are detected by a commercially available LFA. We coupled this system, named Vigilant (VirD2-dCas9 guided and LFA-coupled nucleic acid test), to reverse transcription-recombinase polymerase amplification to detect SARS-CoV2 in clinical samples. Vigilant exhibited a limit of detection of 2.5 copies/µL, comparable to CRISPR-based systems, and showed no cross-reactivity with SARS-CoV1 or MERS. Vigilant offers an easy-to-use, rapid, cost-effective, and robust detection platform for SARS-CoV2.


Asunto(s)
COVID-19 , ARN Viral , Sistemas CRISPR-Cas , Humanos , Transcripción Reversa , SARS-CoV-2 , Sensibilidad y Especificidad
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