RNAi strategies for control of whitefly
Inventors
Wintermantel, William M. • Kaur, Navneet • Hunter, Wayne B.
Assignees
US Department of Agriculture USDA
Publication Number
US-11104914-B2
Publication Date
2021-08-31
Expiration Date
2039-08-27
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Abstract
The present disclosure provides compositions and methods utilizing double strand ribonucleic acid (dsRNA) to control insects, including whiteflies. More particularly, the present invention relates to several specific synthetic dsRNAs that induce RNA interference (RNAi) in the target insects and methods of delivering the dsRNAs to them, such as allowing feeding on plants treated with, or transgenically expressing, the dsRNAs.
Core Innovation
The invention provides compositions and methods utilizing double-stranded ribonucleic acid (dsRNA) to control insects, specifically whiteflies such as Bemisia tabaci MEAM1. It focuses on several specific synthetic dsRNAs that induce RNA interference (RNAi) in target insects and methods of delivering these dsRNAs through feeding on plants treated with, or transgenically expressing, the dsRNAs.
The problem addressed is that whitefly is a serious agricultural pest affecting important crops like tomato, cotton, and cassava. Current management relies heavily on broad spectrum insecticides, which has led to insecticide-resistant whitefly populations, reducing available control options. There is a need for alternative means to manage whitefly.
RNA interference (RNAi) is a natural gene silencing mechanism in eukaryotes and can be triggered by exogenous dsRNA to silence genes with high sequence homology. Whiteflies possess RNAi pathway genes, indicating they are susceptible to RNAi approaches. The invention describes multiple dsRNAs targeting novel whitefly gene sequences, methods of delivering dsRNA via transgenic plants or treated plants, and demonstrates efficacy in reducing whitefly survival, thus providing a precise, species-specific strategy for whitefly control that reduces risk to beneficial insects.
Claims Coverage
The claims include two main inventive features directed to specific dsRNA compositions and corresponding DNA molecules encoding them with defined sequence complementarity.
dsRNA composition targeting SEQ ID NO: 3 with specified sequence complementarity
A double-stranded ribonucleic acid (dsRNA) comprising a first strand having at least 75% complementarity to the full length of SEQ ID NO: 3 and a second strand complementary to the first strand, with embodiments including at least 95% complementarity and capability of inducing RNA interference when ingested by an insect, such as Bemisia tabaci.
DNA molecule encoding dsRNA targeting SEQ ID NO: 3 expressed in a host cell
A DNA molecule comprising a promoter functional in a host cell and heterologous DNA encoding a dsRNA with a first strand having at least 75% complementarity to the full length of SEQ ID NO: 3 and a second strand complementary to the first strand, wherein the host cell can be a plant cell.
These claims cover both the synthetic dsRNA molecules targeting a critical whitefly gene sequence and nucleic acid constructs enabling expression of such dsRNA in host cells, focusing on sequence complementarity to SEQ ID NO: 3 for RNAi-based insect control.
Stated Advantages
The dsRNAs induce whitefly mortality effectively when ingested, providing a species-specific insect control method.
The RNAi approach circumvents issues of insecticide resistance common with conventional broad spectrum insecticides.
Delivery methods via transgenic plants or topical application to plants allow economical, efficient, and environmentally safer pest management.
Documented Applications
Control of whitefly Bemisia tabaci MEAM1, a significant agricultural pest attacking tomato, cotton, cassava, and cucurbits plants.
Delivery of insecticidal dsRNA to whiteflies via feeding on plants expressing dsRNA transgenically or treated with exogenous dsRNA solutions.
Use in transient assays and agroinfiltration of cassava leaves to induce RNAi and achieve mortality in cassava super-abundant whiteflies.
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