Loss of function alleles of PtEPSP-TF and its regulatory targets in rice
Inventors
Xie, Meng • Chen, Jin-Gui • GUNTER, Lee E. • JAWDY, Sara S. • Muchero, Wellington • Tuskan, Gerald • Zhang, Jin
Assignees
US Department of Energy • UT Battelle LLC
Publication Number
US-11473086-B2
Publication Date
2022-10-18
Expiration Date
2039-06-19
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Abstract
The present disclosure provides genetically modified plants, plant cells and plant tissues that show reduced lignin content as compared to a control plant which was not genetically modified. In addition, the disclosure provides methods of regulating lignin content in a plant. The disclosure also provides methods of producing bioproducts using the genetically modified plants of the instant disclosure.
Core Innovation
The invention provides genetically modified plants, plant cells, and plant tissues with reduced lignin content compared to control plants that are not genetically modified, achieved by introducing mutations in the PtrEPSP-TF gene or in transcription factors regulated by PtrEPSP-TF. The mutations cause loss of DNA binding activity of the PtrEPSP-TF protein or altered expression of regulated transcription factors, thereby modulating lignin synthesis in the plant. The proposed genetic modifications can be introduced using genome editing or nucleic acid inhibitors, allowing precise control of lignin content.
The problem addressed arises from the complexity and significance of the phenylpropanoid pathway in plants, which regulates the biosynthesis of lignin and secondary metabolites essential for plant structure, biomass recalcitrance, and stress tolerance. Understanding and manipulating this pathway in rice and other plants is needed to enhance sustainable agriculture, improve biofuel production, and increase the nutritional quality of forage crops. The current limitation in controlling lignin content in monocot plants like rice, which naturally lack the transcriptional regulatory domain (HTH motif) found in the PtrEPSP-TF of Populus, limits efficient biomass processing for bioenergy and related bioproducts.
The invention solves this problem by identifying and utilizing loss of function alleles of PtrEPSP-TF and its regulatory targets, enabling genetic modifications that reduce lignin content and alter cell wall biosynthesis. This is demonstrated in both dicot and monocot plants, including rice, where expression of archetypic or mutant PtrEPSP-TF affects lignin biosynthesis genes and regulatory transcription factors such as MYB46, MYB4, MYB58, SND2, VIN2, XND1, MYB48, MYB3R1, MYB3R3, and NAC047. Methods embody genome editing techniques like CRISPR/Cas to introduce specific mutations, leading to modified lignin biosynthesis and enhanced sugar release for biofuel production.
Claims Coverage
The claims include four independent claims describing genetically modified Oryza plants expressing PtrEPSP-TF with specific mutations, and corresponding methods for producing such plants and bioproducts.
Genetic modification of Oryza plants with PtrEPSP-TF mutations
A genetically modified plant from the genus Oryza expressing an exogenous nucleic acid encoding Populus trichocarpa PtrEPSP-TF harboring a mutation corresponding to amino acid 364 of SEQ ID NO: 7, resulting in loss of DNA binding activity and reduced lignin content, exemplified by sequences in SEQ ID NO: 4.
Method of introducing mutated PtrEPSP-TF in Oryza plants
Introducing into an Oryza plant an exogenous nucleic acid encoding PtrEPSP-TF with a mutation at a position corresponding to amino acid 364 of SEQ ID NO: 7, wherein the mutated protein lacks DNA binding activity and reduces lignin content.
Production of bioproducts from genetically modified plants
Subjecting the genetically modified Oryza plants expressing mutated PtrEPSP-TF to bioproduct conversion processes to produce products including bioenergy products, biomaterials, biopharmaceuticals, and biocosmetics, with ethanol and ethanol fermentation processes specifically claimed.
Production of pulp or paper from genetically modified plants
Producing pulp or paper from genetically modified Oryza plants or plant cells/tissues expressing mutated PtrEPSP-TF as defined in the claims.
The claims cover genetically modified rice plants expressing PtrEPSP-TF proteins with mutations impairing DNA binding activity and methods for creating these plants and using them for bioproduct or pulp/paper production, emphasizing control over lignin content via specific PtrEPSP-TF mutations.
Stated Advantages
Reduced lignin content in genetically modified plants leading to decreased cell wall recalcitrance and increased sugar release for biofuel production.
Modulation of phenylpropanoid pathway gene expression to improve biomass characteristics in both dicot and monocot plants.
Enabling precise genetic modifications using genome editing techniques to reduce lignin without introducing exogenous genes.
Application to important food and bioenergy crops, expanding utilities for sustainable agriculture and improved biofuel feedstocks.
Documented Applications
Production of bioenergy products including ethanol through fermentation processes using genetically modified plants with altered lignin content.
Manufacture of biomaterials, biopharmaceuticals, and biocosmetics from genetically modified plants.
Production of pulp or paper from genetically modified plants or plant tissues with reduced lignin content.
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