Methods of improving mycorrhization in plants and genetically modifed plants with improved mycorrhization
Inventors
Muchero, Wellington • LABBE, Jessy L. • GUNTER, Lee E. • Chen, Jin-Gui • JAWDY, Sara S. • Yang, Xiaohan • Tuskan, Gerald A. • Wang, Juan • Czarnecki, Olaf • Ranjan, Priya
Assignees
US Department of Energy • UT Battelle LLC • University of Tennessee Research Foundation
Publication Number
US-11028404-B2
Publication Date
2021-06-08
Expiration Date
2039-07-24
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Abstract
The present disclosure is directed to methods of improving mycorrhization in a plant or plant cell. Another aspect of this disclosure is directed to a genetically modified plant or plant cell with improved mycorrhization.
Core Innovation
The invention provides methods for improving mycorrhization in plants or plant cells by expressing an exogenous nucleic acid encoding a LecRLK1 variant or homolog. A key aspect is the use of a P. trichocarpa LecRLK1 (PtLecRLK1) variant or homolog comprising the amino acid sequence shown by SEQ ID NO: 78. Expression of LecRLK1 can be controlled by root-specific promoters such as DR5, PtrDP3, and PtrMX3 to enhance mycorrhizal symbiosis specifically in root tissues.
The background highlights the significance of mycorrhizal symbiosis for improving carbon sequestration, nutrient availability, soil remediation, and water use efficiency, particularly emphasizing Populus species as hosts for ectomycorrhizal fungi like Laccaria bicolor. However, it notes that molecular mechanisms underlying species-specific mycorrhizal interactions, such as Laccaria's preference for P. trichocarpa over P. deltoides, were previously unknown and no host genetic determinants explaining this specificity had been identified.
The invention addresses this gap by identifying PtLecRLK1 as a positive regulator of Populus-Laccaria colonization, demonstrated by genetic mapping and functional studies showing increased root colonization with PtLecRLK1 presence. Transgenic expression of PtLecRLK1 in other plants like Arabidopsis led to suppression of plant defense responses upon Laccaria inoculation and altered metabolite profiles consistent with enhanced mycorrhization, establishing PtLecRLK1's role in facilitating and improving mycorrhizal symbiosis.
Claims Coverage
The patent includes 4 independent claims covering methods, genetically modified plants, expression vectors, and plants containing those vectors with LecRLK1 variants, focusing on improving mycorrhization by expressing LecRLK1 variants or homologs.
Method for improving mycorrhization by expressing LecRLK1 variants
A method comprising expressing an exogenous nucleic acid encoding a Lectin receptor-like kinase 1 (LecRLK1) variant or homolog in a plant or plant cell, improving mycorrhizal symbiosis. The LecRLK1 variant or homolog has at least 98% amino acid identity to SEQ ID NO: 78.
Genetically modified plants expressing LecRLK1 variants
Genetically modified plants or plant cells comprising an exogenous nucleic acid encoding a LecRLK1 variant or homolog expressed in the plant or plant cell, wherein the variant or homolog has at least 98% amino acid identity to SEQ ID NO: 78.
Expression vectors encoding LecRLK1 variants
An expression vector comprising a nucleotide sequence encoding a LecRLK1 allelic variant or homolog operably linked to a heterologous regulatory region functional in a plant or plant cell, where the LecRLK1 variant or homolog has at least 98% amino acid identity to SEQ ID NO: 78.
Plants or plant cells containing expression vectors
A plant or plant cell comprising the expression vector comprising a LecRLK1 variant or homolog operably linked to a functional regulatory region, where the variant or homolog has at least 98% amino acid identity to SEQ ID NO: 78.
The claims establish coverage over methods of improving mycorrhization by expressing LecRLK1 variants, genetically modified plants and plant cells expressing such variants, expression vectors for LecRLK1 variants, and plants or cells containing these vectors, wherein the LecRLK1 variants have high sequence identity to SEQ ID NO: 78 and improve mycorrhizal interactions.
Stated Advantages
Improved mycorrhization leads to enhanced plant biomass yield, for example, doubling biomass yield in Populus colonized by Laccaria bicolor.
The method enables plants to produce more biomass and crop product under conditions of low water availability, drought, or poor soils.
Provides an immediate target for engineering mycorrhizal symbiosis into economically important crops to enhance nutrient and water acquisition in marginal lands.
Documented Applications
Improvement of biomass production and crop yield in economically important perennial forestry crops such as Populus.
Application in bioenergy crops including Populus, switchgrass, corn, and other lignocellulosic biomass sources, as well as model plants like Salix, Miscanthus, rice, wheat, soybean, and Medicago.
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