Fruit-specific promoters
Inventors
Thomson, James G. • Thilmony, Roger L. • DASGUPTA, Kasturi • Dardick, Christopher D.
Assignees
US Department of Agriculture USDA
Publication Number
US-11091768-B2
Publication Date
2021-08-17
Expiration Date
2039-05-23
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Abstract
The present disclosure provides genetic constructs containing a promoter that is useful in driving fruit-specific expression in plants. Further provided are expression vectors, transgenic plants and plant parts containing such genetic constructs, as well as uses thereof.
Core Innovation
The invention provides genetic constructs containing promoters useful for driving fruit-specific expression in plants. These include novel promoters derived mainly from citrus and plum species, operably linked to heterologous nucleotide sequences encoding products of interest. The invention also encompasses expression vectors, transgenic plants and plant parts containing these genetic constructs, along with methods for modifying fruit phenotypes using these constructs.
The problem addressed is the limited availability of fruit-specific promoters suitable for genetic engineering across many fruit species. Traditional breeding for improved fruit traits is challenged by factors such as large plant size, long juvenile phases, and limited genetic gains. Genetic engineering requires suitable regulatory sequences like promoters that enable tissue- and development-specific expression to minimize adverse effects. Although some fruit-specific promoters have been isolated, mostly from tomato and few other species, robust and reliable fruit-specific promoters remain inadequate for engineering fruit traits such as growth, ripening, nutritional quality, and post-harvest shelf life.
Claims Coverage
The claims include one independent claim directed to a genetic construct containing a specific promoter operably linked to a heterologous nucleotide sequence, and related claims covering expression vectors, transgenic plants and plant parts, as well as methods for modifying fruit phenotypes. The main inventive features describe the characteristics of the promoter and its use in controlling fruit-specific expression.
Genetic construct comprising fruit-specific promoters
A genetic construct comprising a promoter comprising SEQ ID NO: 1 or a sequence with at least 96% identity thereto, operably linked to a heterologous nucleotide sequence encoding a product of interest.
Product of interest as RNA or polypeptide in metabolic pathways
The product of interest encoded by the heterologous nucleotide sequence is either an RNA molecule or a polypeptide. The polypeptide may be involved in an anthocyanin, tocopherol, fatty acid, carotenoid, lycopene, betalain, or flavonoid metabolic pathway, including transcription factors and enzymes such as MYB transcription factor, phytoene synthase (PSY), lycopene cyclase (LCY), or DXP synthase (DXS).
Expression vector containing the genetic construct
An expression vector comprising the genetic construct containing the fruit-specific promoter and heterologous nucleotide sequence as described.
Transgenic plant and plant parts containing the genetic construct
A transgenic plant containing the genetic construct, and plant parts (stem, branch, root, leaf, flower, fruit, seed, cutting, bud, cell or portions thereof) containing the genetic construct.
Method of modifying fruit phenotype using the genetic construct
A method to modify a fruit phenotype by transforming a plant cell with the genetic construct, regenerating the plant, and growing the regenerated plant to produce fruit with a modified phenotype associated with expression of the product of interest.
Modification of diverse fruit phenotypes and applicable plant species
The fruit phenotype modifications include size, weight, color, shape, firmness, glossiness, flavor, aroma, secondary metabolite content, peel thickness, seed number, juice quality and content, taste, color and yield. The applicable plants include citrus species (orange, mandarin, lime, grapefruit, lemon, pomelo, citron, papeda) and Prunus species.
The patent claims focus on genetic constructs comprising novel fruit-specific promoters directing expression mainly in fruit tissues, enabling expression of products affecting diverse fruit traits, covering their incorporation into expression vectors, transgenic plants, plant parts, and methods for modifying fruit traits.
Stated Advantages
The seedless fruit phenotype produced by transgenic tomato plants with a genetic construct containing the SEQ ID NO: 4 promoter enables development of seedless fruit cultivars without compromising fruit quality and productivity.
Promoters identified permit fruit-specific expression of transgenes, minimizing adverse effects on other plant tissues and developmental stages.
The ability to direct transgene expression specifically in fruit tissues improves engineering of desirable agronomic and nutritional fruit traits such as growth, ripening, anthocyanin and lycopene content.
Documented Applications
Generation of transgenic fruit plants with modified phenotypes including changes in size, color, shape, firmness, flavor, aroma, secondary metabolite and nutraceutical content, peel thickness, seed number, and juice quality.
Engineering of seedless fruit in tomato by transformation with genetic constructs containing the SEQ ID NO: 4 promoter resulting in seedless fruit production.
Use of fruit-specific promoters to drive expression of genes involved in metabolic pathways such as anthocyanin, tocopherol, fatty acid, carotenoid, lycopene, betalain and flavonoid biosynthesis to improve fruit nutritional quality.
Modification of anthocyanin accumulation and lycopene production in transgenic Arabidopsis, tobacco, tomato and citrus plants using constructs with candidate fruit-specific promoters driving genes encoding regulators or enzymes.
Use of the Arabidopsis FLOWERING LOCUS T gene to accelerate flowering in citrus transgenic plants incorporating fruit-specific promoters for faster fruit trait evaluation.
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