Effect of PpeGID1c on vegetative growth of fruit trees
Inventors
Dardick, Christopher D. • Scorza, Ralph • Hollender, Courtney A.
Assignees
US Department of Agriculture USDA
Publication Number
US-9944940-B2
Publication Date
2018-04-17
Expiration Date
2035-06-11
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Abstract
The genetic basis for a recessive dwarf trait (dw) in peach (Prunus persica) was determined. Using a sequencing-based bulk-segregant mapping strategy, dw was positioned on the distal end of peach chromosome 6. At the center of the mapped locus, a SNP leading to a premature stop codon was identified within the coding region of a homolog of the Giberellic Acid (GA) receptor GID1 (GA Insensitive Dwarf 1). Silencing of GID1c in the closely related species Prunus domestica (plum) led to dwarf phenotypes with shortened internodes similar to dw/dw peaches. The degree of GID1c silencing corresponded to the degree of dwarfing. Anatomical expression studies showed that GID1c was highly expressed in all actively growing peach tissues, but more predominant in apical meristems and roots. These data establish that GID1c serves a primary role in the rapid growth and elongation of peach vegetative tissues, thus providing new methods to control tree size without impacting flower or fruit development.
Core Innovation
The invention identifies the GID1c gene as the causative gene for the brachytic dwarf phenotype in peach (Prunus persica). This gene encodes a gibberellic acid (GA) receptor, and a nonsense mutation within its coding region leads to a recessive dwarf trait characterized by short internodes, thick woody stems, elongated leaves, dwarf root systems, very slow growth, but normal flower and fruit development. The invention establishes that silencing GID1c expression causes dwarf phenotypes in Prunus species such as peach and plum, demonstrating its primary role in rapid growth and elongation of vegetative tissues. This discovery enables new methods to control tree size without impacting reproductive development.
The problem addressed is the labor-intensive and costly management of tree size in agricultural production, which relies on grafting, pruning, dwarfing rootstocks, and hormone applications. Existing genetic manipulations of GA pathways in trees often negatively affect flowering and fruit development, limiting utility. Peach dwarf traits (dw) were known but their genetic basis remained unknown. The invention solves this by mapping the dwarf locus and identifying GID1c, enabling genetic control of tree architecture to allow high-density planting, reduced labor and chemical inputs, and improved management in fruit trees.
Claims Coverage
The claims include one independent claim focusing on a RNAi construct targeting the GID1c gene and associated compositions and methods for reducing tree internode length in Prunus species.
RNAi construct comprising GID1c sense and antisense fragments
A double-stranded RNA interference (RNAi) construct comprising a sense polynucleotide fragment of GID1c gene sequence SEQ ID NO:4 and its complementary antisense fragment, designed to specifically target GID1c for silencing.
Vector with promoter operably linked to RNAi construct
A recombinant vector comprising a promoter operably linked to the RNAi construct to drive expression of the GID1c-targeting double stranded RNA in host cells.
Transformed host cells of Prunus species
Isolated host cells, including Prunus cells such as those from peach, plum, cherry, Japanese plum, or apricot, transformed with the recombinant vector comprising the GID1c RNAi construct.
Method to produce transformed Prunus plants with shorter internodes
A method comprising transforming wild-type Prunus plant cells with the recombinant vector encoding the GID1c RNAi construct, selecting transgenic cells expressing the construct that forms double stranded RNA, and regenerating transgenic plants exhibiting reduced GID1c expression and shorter internodes compared to wild type.
Transgenic Prunus plants and progeny with brachytic dwarf phenotype
Transgenic Prunus plants and their progeny containing the RNAi construct that produce double stranded RNA targeting GID1c, exhibiting shorter internodes and altered plant architecture relative to non-transformed plants.
Transgenic Prunus cells and seeds producing RNAi construct
Transgenic Prunus cells and seeds transformed with the vector that produces RNAi targeting GID1c, resulting in plants with reduced GID1c expression and dwarf phenotypes with shortened internodes.
Overall, the claims cover RNAi constructs targeting the GID1c gene, vectors and host cells for delivery, and methods and compositions for producing transgenic Prunus plants with reduced vegetative growth characterized by shorter internodes and dwarf stature.
Stated Advantages
Allows control of tree size in Prunus species through genetic silencing of GID1c without impacting flowering or fruit development.
Enables reduction of labor, material, and chemical costs associated with management of tree architecture such as pruning and use of dwarfing rootstocks.
Facilitates high-density planting and mechanized harvesting due to smaller tree stature, improving productivity and reducing environmental inputs.
Offers a biotechnological method to directly manipulate tree size, overcoming limitations of prior GA hormone or downstream pathway manipulations that impaired fruit development.
Documented Applications
Controlling vegetative growth and size of fruit trees of the Prunus genus, including peach, plum, cherry, Japanese plum, and apricot.
Producing transgenic Prunus plants with brachytic dwarf traits characterized by short internodes, thick stems, elongated leaves, dwarf root systems, and slower growth to improve orchard management and reduce associated costs.
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