Sorghum-derived transcription regulatory elements predominantly active in root hair cells and uses thereof
Inventors
Baerson, Scott R. • Pan, Zhiqiang • Polashock, James J
Assignees
US Department of Agriculture USDA
Publication Number
US-10000762-B2
Publication Date
2018-06-19
Expiration Date
2035-05-20
Interested in licensing this patent?
MTEC can help explore whether this patent might be available for licensing for your application.
Abstract
Transcription regulatory elements, namely promoter and terminator sequences, obtained from Sorghum bicolor that drive RNA transcription predominately in root hair cells are described, as well as cassettes, expression vectors, and genetically modified plants containing these transcription regulatory elements. The genetically modified plants can be gymnosperms, dicots, or monocots. Methods of directing transcription of a heterologous polynucleotide under control of these transcription regulatory elements in a genetically modified plant's root hair cells are also provided.
Core Innovation
This invention describes transcription regulatory elements, specifically promoter and terminator sequences derived from Sorghum bicolor, that drive RNA transcription predominantly in root hair cells of plants. These elements include DNA sequences with SEQ ID NOs: 1, 3, 5, 7, 12, 16, 20, and 24 for promoters and SEQ ID NOs: 2, 4, 6, 8, 13, 17, 21, and 25 for terminators. The invention includes cassettes, expression vectors, and genetically modified plants containing these regulatory elements, which can be gymnosperms, dicots, or monocots. Methods to direct transcription of a heterologous polynucleotide under the control of these elements in a genetically altered plant's root hair cells are also provided.
The problem addressed is the need for novel promoters that can target heterologous gene expression specifically and strongly in root hair cells of genetically altered plants. Existing promoters are mostly constitutive or active in multiple tissues, thus there is a lack of transcription regulatory elements with root hair cell specificity. Targeting root hair cells is crucial because they represent the majority of root surface area, are primary sites for nutrient and water uptake, and are involved in interactions with soil microbes, including nodulation in legumes. The invention aims to avoid the adverse effects of non-cell type-specific expression, such as yield reduction, and enable high-level root hair-specific transgene expression to support a range of agronomic traits.
The invention presents a solution by isolating and characterizing promoters and terminators that are highly active and predominantly specific to root hair cells in Sorghum bicolor. The promoters and terminators are obtainable as DNA sequences with at least 95% identity to the specified SEQ ID numbers. Constructed cassettes and expression vectors containing these elements operably linked to heterologous polynucleotides direct preferential transcription and expression in root hair cells. The elements have been validated in monocot and dicot model plants (Oryza sativa and Arabidopsis thaliana) and provide novel tools for targeted gene expression affecting important traits such as disease resistance, nutrient uptake, stress tolerance, and bioremediation.
Claims Coverage
The patent contains one independent cassette claim, one independent genetically altered plant claim, and two independent method claims, each incorporating a promoter with SEQ ID NO: 7. The main inventive features relate to the promoter's ability to selectively regulate heterologous polynucleotide transcription predominantly in root hair cells and the inclusion of specific terminator sequences.
Promoter comprising SEQ ID NO: 7 capable of regulating transcription in plant cells
A cassette comprising a promoter with the nucleotide sequence of SEQ ID NO: 7 operably linked to a heterologous polynucleotide that encodes a protein or RNA, with capacity to regulate transcription within plant cells.
Promoter active predominantly in root hair cells
The promoter of the cassette is predominantly active in a plant's root hair cells, ensuring tissue-specific transcription of the linked heterologous polynucleotide.
Inclusion of terminator sequences operably linked to the heterologous polynucleotide
The cassette optionally comprises a terminator sequence operably linked to the 3′ end of the heterologous polynucleotide, where the terminator sequence is selected from SEQ ID NOs: 2, 4, 6, or 8 or sequences at least 95% identical thereto.
Genetically altered plant or progeny containing the cassette
Plants (gymnosperms, monocots, or dicots), parts thereof, or progeny are genetically altered to contain the cassette comprising the promoter of SEQ ID NO: 7 operably linked to a heterologous polynucleotide, enabling root hair-specific expression of the encoded protein or RNA.
Methods of selectively directing transcription and producing protein or RNA in root hair cells
Methods involving introducing the cassette containing SEQ ID NO: 7 promoter operably linked to a heterologous polynucleotide into wild-type plant cells, selecting genetically altered plants that contain the cassette, and growing them to produce protein or RNA predominantly in root hair cells. These methods may include terminators as described.
The claims cover cassettes with the specified promoter active predominantly in root hair cells, optionally including specific terminators, genetically altered plants containing such cassettes, and methods of producing proteins or RNA by selectively directing transcription in root hair cells using these elements.
Stated Advantages
The transcription regulatory elements enable high-level root hair-specific expression of heterologous polynucleotides.
They minimize potential adverse effects resulting from non-root hair cell-specific expression, such as reductions in crop yield.
These elements provide tools for manipulating gene expression in a cell type critical to plant growth, nutrient uptake, and interactions with the soil environment.
Documented Applications
Expression of genes that improve disease resistance in genetically altered plants.
Enhancement of nutrient uptake into root hair cells.
Improvement of resistance to colonization by soil-borne parasites.
Promotion of colonization by beneficial rhizosphere-associated microorganisms.
Enhancement of stress tolerance and water uptake in plants.
Facilitation of bioremediation through root hair cell expression.
Reduction of competition from neighboring plants via allelochemical production by root hair cells.
Enhancement of nitrogen fixation mediated by root hair cells.
Interested in licensing this patent?