Targeted control of pests and pathogens by plant delivery of 2′F-ANA-oligonucleotides
Inventors
Hunter, Wayne B. • AISHWARYA, VEENU
Assignees
Aum Life Tech Inc • US Department of Agriculture USDA • AUM Lifetech Inc
Publication Number
US-11946058-B2
Publication Date
2024-04-02
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 provides 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. These oligonucleotides combine at least one 2′-deoxy-2′-fluoroarabinonucleotide (2′F-ANA)-modified nucleotide and at least one 2′-deoxyribonucleotide, with specific placement of 2′F-ANA-modified nucleotides according to designated formulas. The oligonucleotides are designed to induce RNA silencing targeting specific pathogens and insect pests when ingested by insects via treated plant material or artificial feeding sources.
The problem being solved addresses the difficulty in targeting plant pathogens, especially bacteria, due to limited approved antibiotics for crops and concerns about antibiotic resistance development. Traditional pesticides and antibiotics pose issues such as environmental impact, resistance, high costs, regulatory restrictions, and safety for beneficial species. Thus, there is a need for non-antibiotic, highly specific compositions and methodologies capable of controlling internal plant pathogens and endosymbionts of insect pests without creating genetically modified plants.
The invention tackles these challenges by applying antisense oligonucleotides (ASOs) with 2′F-ANA modifications to plants via methods such as foliar sprays, root soaks, trunk injections, and soil treatment. These ASOs exhibit increased stability and specificity, allowing systemic movement throughout plant tissues. Insects feeding on treated plants ingest these ASOs, which induce RNA silencing leading to control or mortality of target bacteria and insect pests such as Diaphorina citri and Diaprepes abbreviatus. The approach also reduces pesticide and antibiotic use while preserving beneficial host microbiota.
Claims Coverage
The patent contains multiple independent claims focusing on methods of inducing RNA silencing and controlling insects and bacteria using 2′F-ANA-modified oligonucleotides with specified sequences and compositions.
Method of inducing RNA silencing in plant-chewing or phloem-feeding insects
Providing an oligonucleotide comprising at least one 2′F-ANA-modified nucleotide and at least one 2′-deoxyribonucleotide, with 2′F-ANA nucleotides positioned according to any of Formulas 2-16, and having sequences selected from SEQ ID NOs: 39-46, 48-69, and 71-76. The oligonucleotide is provided to the insect in a manner whereby it ingests the oligonucleotide, thereby inducing RNA silencing.
Oligonucleotide ingestion via plant material or artificial diet
The insect ingests the oligonucleotide by consuming plant material containing the oligonucleotide or through artificial diet, sugar solution, or bait material, with application methods including root soak, injection, or foliar spray.
Target insect and plant species
The insect is Diaphorina citri or Diaprepes abbreviatus, and the plant is a citrus plant (including orange, lemon, clementine, lime, grapefruit, pomelo, citron, mandarin, tangelo) or a potato plant.
Method of controlling plant-chewing or phloem-feeding insects
Providing the specified oligonucleotide with 2′F-ANA modifications and sequences as above, ingested by the insect, thereby inducing RNA silencing and causing a detrimental effect, such as increased mortality compared to insects not exposed to the oligonucleotide.
Method of inducing RNA silencing in Diaphorina citri or Diaprepes abbreviatus
Contacting D. citri or D. abbreviatus with the oligonucleotide comprising at least one 2′F-ANA-modified nucleotide and at least one 2′-deoxyribonucleotide in an amount sufficient to induce RNA silencing, with 2′F-ANA nucleotides positioned according to any of Formulas 2-16 and sequences from SEQ ID NOs: 39-46, 48-69, and 71-76. The contacting comprises ingestion of phloem or plant tissue containing the oligonucleotide depending on the insect species.
The independent claims cover methods of delivering specific 2′F-ANA-modified oligonucleotides to certain insects and plants to induce RNA silencing and control of plant-chewing and phloem-feeding insects and their associated bacterial pathogens through ingestion of treated plant tissues or artificial feeding means, with defined nucleotide compositions and positional modifications.
Stated Advantages
Provides a non-antibiotic and highly specific control method for difficult-to-target plant bacterial pathogens and insect endosymbionts.
Improves stability and resistance to environmental degradation compared to other nucleotide-based strategies such as dsRNA.
Reduces pesticide and antibiotic use without the need to create genetically modified plants.
Allows systemic distribution of oligonucleotides through various plant tissues and is effective across multiple plant species and diverse arthropod insect orders.
Documented Applications
Controlling plant-chewing and phloem-feeding insects including Asian citrus psyllid (Diaphorina citri) and citrus root weevil (Diaprepes abbreviatus).
Controlling bacterial plant pathogens such as Candidatus Liberibacter asiaticus in citrus and Candidatus Liberibacter solanacearum in potato and other Solanaceous crops.
Reducing bacterial endosymbionts within insect vectors by feeding on treated plant tissues or artificial diets containing the oligonucleotides.
Application in horticultural and agricultural crops including citrus, potato, grapevines, woody ornamentals, sunflowers, basil, and okra.
Delivery of oligonucleotides to plants by foliar spray, root soak, trunk injection, soil treatment, and incorporation into baits or artificial feeding solutions.
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