Targeted control of pests and pathogens by plant delivery of 2'F-ANA-oligonucleotides
Inventors
Hunter, Wayne B. • AISHWARYA, VEENU
Assignees
US Department of Agriculture USDA • AUM Lifetech Inc
Publication Number
US-11254945-B2
Publication Date
2022-02-22
Expiration Date
2039-07-03
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Abstract
Herein is disclosed synthetic oligonucleotides comprising 2′F-ANA nucleosides that can be utilized to control plant-chewing and phloem-feeding insects, bacteria present in such insects, and bacteria present in plants. The novel approaches and materials provided herein allow for reduction of pesticide and antibiotic use without the need to create genetically modified plants.
Core Innovation
The invention discloses synthetic oligonucleotides comprising 2′-deoxy-2′-fluoroarabinonucleotide (2′F-ANA)-modified nucleotides combined with 2′-deoxyribonucleotides, designed to specifically induce RNA silencing in plant-chewing and phloem-feeding insects, bacteria present in these insects, and bacteria present in plants. These oligonucleotides are capable of targeting key mRNA transcripts of pests and pathogens, offering a targeted means of control without the need to create genetically modified plants.
The problem addressed is the difficulty in controlling plant pathogens, particularly bacterial pathogens that impact crops, such as Candidatus Liberibacter asiaticus and solanacearum, which cause significant agricultural losses. Existing treatments primarily rely on antibiotics and pesticides which have drawbacks including cost, regulatory hurdles, resistance development, environmental concerns, and harm to beneficial microbes. There is a need for novel, non-antibiotic compositions and methodologies that can safely and specifically target internal pathogens of plants or endosymbiotic bacteria in insect pests while minimizing impact on beneficial microbiota.
The invention provides compositions and methods whereby oligonucleotides containing 2′F-ANA modifications are delivered to plants through various means such as foliar spray, soil soak, or trunk injection. These oligonucleotides are absorbed and translocated systemically in plant tissues and subsequently ingested by feeding insects. Upon ingestion, RNA silencing mechanisms are induced in the target bacteria or insect pest, resulting in detrimental effects such as reduced pathogen titer or increased insect mortality. This approach leverages the increased stability and specificity of 2′F-ANA oligonucleotides compared to other nucleotide-based treatments and addresses limitations encountered with topically applied RNA interference methods.
Claims Coverage
The patent claims define several inventive features related to methods of controlling bacteria and insects using 2′F-ANA-modified oligonucleotides, delivered via various means to plants and insects.
Method of controlling specified bacteria present in insects
A method involving contacting a food source edible by an insect with an oligonucleotide comprising at least one 2′F-ANA-modified nucleotide positioned according to Formulas 2-16 that targets mRNA in bacteria (Candidatus Liberibacter asiaticus or solanacearum), allowing ingestion by the insect to induce RNA silencing in the bacteria and thereby control them.
Use of specific oligonucleotide sequences targeting bacterial mRNAs
Utilization of oligonucleotides selected from SEQ ID NOs: 4-38 for targeting and controlling bacteria present in insects or plants.
Application of oligonucleotide via various food sources
Provision for delivering oligonucleotides through food sources such as plants, bait materials, artificial diets, or sugar solutions, with specific methods for contacting plants including root soaking, injection, or foliar spraying.
Method of controlling bacteria present in plant tissues
A method involving applying an oligonucleotide with at least one 2′F-ANA-modified nucleotide to plants (such as citrus or potato) so that the oligonucleotide distributes through plant tissues, induces RNA silencing in the target bacterium (Candidatus Liberibacter asiaticus or solanacearum), thereby causing a detrimental effect.
The claims cover innovative methods using 2′F-ANA-modified oligonucleotides for targeted RNA silencing to control plant pathogens and insect-borne bacteria, employing specific nucleotide modifications and delivery methods to plants and insects, addressing both bacterial pathogens inside plants and those vectored by insect pests.
Stated Advantages
Allows reduction of pesticide and antibiotic use without creating genetically modified plants.
Provides high specificity for genetic targets due to antisense oligonucleotide binding.
Demonstrates chemical and environmental stability superior to traditional dsRNA or nucleotide-based treatments.
Targets internal pathogens of plants and endosymbionts of insect pests in a species-specific manner, reducing damage to beneficial microbiota.
Applicable to diverse plant species and arthropod orders, enabling broad use across horticulture and agriculture.
Documented Applications
Control of plant-chewing and phloem-feeding insect pests such as Diaphorina citri and Diaprepes abbreviatus through ingestion of treated plant tissues or artificial diets containing 2′F-ANA oligonucleotides.
Treatment of bacterial plant pathogens including Candidatus Liberibacter asiaticus in citrus and Candidatus Liberibacter solanacearum in potato by application of 2′F-ANA oligonucleotides to plants via foliar spray, soil soak, or trunk injection.
Reduction of bacterial titer in insect vectors by feeding them oligonucleotide-treated plant material or artificial diets to induce RNA silencing of bacterial transcripts within the insect.
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