DRO1 related genes influence lateral root orientation and growth in Arabidopsis and Prunus species
Inventors
Dardick, Christopher D. • Guseman, Jessica M. • Hollender, Courtney A.
Assignees
US Department of Agriculture USDA
Publication Number
US-10513708-B2
Publication Date
2019-12-24
Expiration Date
2037-09-13
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Abstract
Root orientation, or angle, is an important component of root architecture and depth of the root system. We have determined that DRO1 and DRO1-related genes are present across diverse plant phyla and fall within the IGT gene family. DRO1, present in both Arabidopsis and peach, displayed root specific expression patterns. AtDRO1 is predominantly expressed in both the root vasculature and root tips in a distinct developmental pattern. Mutation of AtDRO1 led to more horizontal lateral root angles; over-expression of AtDRO1 under a constitutive promoter reduced lateral root angles and resulted in shoot phenotypes including upward leaf curling, shortened siliques, and narrow lateral branch angles. Over-expression of PpeDRO1 in plum (Prunus domestica) led to deeper rooting phenotypes. These data establish that DRO1-related genes serve a role in altering root architecture, providing a method for drought avoidance.
Core Innovation
The invention identifies and isolates the PpeDRO1 gene from peach and its role, along with DRO1-related genes, in controlling root orientation and overall root system depth in Arabidopsis and Prunus species. Overexpression of PpeDRO1 and its homologs results in altered root architectures characterized by narrower lateral root angles and deeper root systems, which confer drought avoidance advantages. This gene is part of the IGT family and shows root-specific expression patterns.
The problem addressed by the invention arises from the limited knowledge on genetic control of root growth orientation, which is a critical component of root system architecture affecting plant water and nutrient uptake and stability. While root growth rates and branching are somewhat understood, the regulation of lateral root angle and root depth, especially in dicots and economically important Prunus species, remains insufficiently characterized. Previous research demonstrated DRO1's role in monocots like rice; however, its function and application in dicot species such as peach and plum were unknown.
Through phylogenetic analyses, expression studies, and genetic transformations, the invention demonstrates that DRO1-like genes influence lateral root orientation and root depth in Arabidopsis and Prunus. Mutation of AtDRO1 causes wider lateral root angles, while overexpression reduces lateral root angles and produces deeper rooting phenotypes. Overexpression in plum leads to increased root depth and altered shoot phenotypes, indicating that manipulation of PpeDRO1 expression offers a practical method for altering root architecture to enhance drought tolerance and resource acquisition in fruit tree species.
Claims Coverage
The patent contains multiple independent claims focusing on the expression vector comprising PpeDRO1 and methods of producing genetically altered Prunus plants with modified root architecture.
Expression vector comprising heterologous promoter and PpeDRO1
An expression vector that includes a heterologous promoter operably linked to a polynucleotide encoding PpeDRO1 having the amino acid sequence of SEQ ID NO: 2.
Method for producing genetically altered Prunus plants with altered root architecture
A method comprising transforming wild-type Prunus cells with an expression vector encoding PpeDRO1 (SEQ ID NO: 2), selecting transformed cells producing increased amounts of PpeDRO1, and inducing such cells to grow into genetically altered Prunus plants exhibiting narrower lateral root branch angles and longer root systems compared to wild-type plants.
Genetically altered Prunus plants and progeny expressing elevated PpeDRO1
Genetically altered Prunus plants and their progeny containing a heterologous promoter operably linked to a polynucleotide encoding PpeDRO1 (SEQ ID NO: 2), which produce increased amounts of PpeDRO1 resulting in altered root architectures characterized by narrower lateral root branch angles and longer root systems compared to wild-type plants.
The claims collectively cover molecular constructs for PpeDRO1 expression, methods for generating genetically modified Prunus plants with enhanced root architecture traits, and the genetically altered plants and their progeny themselves, emphasizing the increased PpeDRO1 expression and the resultant distinct root phenotypes.
Stated Advantages
Alteration of root architecture through PpeDRO1 overexpression leads to deeper rooting and narrower lateral root angles, providing enhanced access to water and nutrients.
Deep rooting conferred by DRO1 facilitates drought avoidance, increasing plant yield and survival under water-limited conditions.
Genetically altered plants retain normal flower and fruit development despite altered root traits.
Narrower root systems allow for higher density planting without excessive root competition.
Deeper roots improve plant stability in loose or wet soils.
PpeDRO1 overexpression may enhance vegetative propagation efficiency by promoting rooting on shoot multiplication media.
Documented Applications
Generation of genetically altered Prunus trees (including peach, plum, cherry, Japanese plum, and apricot) with modified root architecture for deeper rooting and drought avoidance.
Use of DRO1-related genes to create rootstocks or ungrafted scions suitable for high density fruit and nut production.
Development of root systems that explore deeper soil layers to improve water and nutrient uptake under moisture-poor conditions.
Application of PpeDRO1 overexpression to enhance vegetative propagation efficiency during plant tissue culture regeneration processes.
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