Compositions and methods comprising endophytic bacterium for application to grasses to increase plant growth, suppress soil borne fungal diseases, and reduce vigor of weedy competitors
Inventors
White, Jr., James F • Kowalski, Kurt P. • Kingsley, Kathryn
Assignees
United States Geological Survey • Rutgers State University of New Jersey
Publication Number
US-12241054-B2
Publication Date
2025-03-04
Expiration Date
2036-07-21
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Abstract
Endophytic bacteria, compositions comprising the same, and methods of use thereof are disclosed which increase the root and shoot growth of grass hosts, suppress growth of soil borne fungal pathogens of host plants, increase resistance of the grass to diseases and reduce competitiveness of distantly related competitor weeds of the crop.
Core Innovation
The invention provides endophytic bacteria strains, compositions comprising these bacteria, and methods for applying them to grasses to enhance plant growth, suppress soil borne fungal diseases, increase disease resistance, and reduce the vigor of weedy competitor plants. Specifically, the method involves inoculating grass plants or seeds with biologically pure endophyte strains, such as Pseudomonas spp., Microbacterium spp., or Enterobacter spp. isolated from Phragmites australis, which are heterologously disposed to the host grass. The bacteria promote one or more of root growth, shoot growth, resistance to salt stress, competition against undesirable plants, and fungal resistance in the resulting plant compared to untreated controls.
The bacterial strains include ones characterized by specific ribosomal DNA sequences (SEQ ID NOS: 1-16) or those with at least 90%, 95%, or 98% identity, with especially preferred strains including Sandy LB4, Sandy LB6, Sandy Y8, RoY12, RoLB13w, WY9y, WY6, West 9, WY14, RiY3, SandyY7w, WY9w, RiLB4, SY1, SY5, WY9w, and Microbacterium oxydans B2. Formulations for application include synthetic seed balls, liquid sprays, or controlled release fertilizers incorporating these bacteria.
The problem addressed arises from invasive grasses such as Phragmites australis dominating native flora and associated ecological communities in North America, partly due to symbiotic microbes enhancing their invasiveness and stress tolerance. There is a need to harness similar microbial associations for beneficial use in cultivated grasses to improve growth, disease resistance, and weed management while reducing reliance on chemical inputs.
Claims Coverage
The claims contain one independent synthetic combination claim and one independent method claim focusing on the application of specific endophytic bacteria from Phragmites to turf and forage grass seeds.
Synthetic combination of bacterial endophytes with seed of turf and forage grass
A synthetic combination comprising at least one purified bacterial population heterologously disposed to turf or forage grass seed, comprising Pseudomonas sp. NRRL B-67482 and at least one seed bacterial endophyte selected from Pseudomonas fluorescens NRRL-B67308 and Microbacterium oxydans NRRL-B67470, present at least 10^3 CFU/seed on the seed surface, and effective to increase root and shoot growth, salt stress resistance, competition with undesirable plants, and fungal resistance in plants grown from the seed. Specific phenotypic characterizations of each bacterial strain include presence or absence of fluorescence under UV light, phosphate solubilization, and protease production.
Method of increasing growth and disease resistance of a grass plant by inoculation
A method of increasing root and shoot growth of a grass plant host by inoculating the plant or seed with the aforementioned synthetic combination, resulting in increased root growth promotion, shoot growth promotion, resistance to salt stress, competition with undesirable plant species, and fungal resistance relative to untreated references. The method also covers suppression of soil borne fungal pathogens and applications to various turf, forage, and food grass species with possible use of seed balls, liquid sprays, or incorporation into controlled release fertilizers.
The independent claims cover a specific synthetic bacterial combination associated with grass seeds and a method of applying this combination to enhance growth, disease resistance, and weed suppression in grasses, employing characterized strains from Phragmites australis that confer multiple agronomic advantages.
Stated Advantages
Increments in root and shoot growth of grass plants.
Suppression of soil borne fungal pathogens leading to reduced damping off and other diseases.
Increased tolerance of grasses to salt stress.
Reduction in competitiveness and increased mortality of distantly related weed seedlings such as dandelion and curly dock.
Potential reductions in the need for chemical fertilizers, fungicides, and herbicides.
Documented Applications
Enhancement of turf and forage grass growth including species like Agrostis spp., Poa spp., Festuca spp., Lolium spp., Cynodon spp., and Danthonia spp.
Improvement of food grass crops such as rice (Oryza sativa), wheat (Triticum aestivum), and maize (Zea maydis).
Suppression and control of soil borne fungal diseases including damping off disease caused by Fusarium oxysporum and Dollar spot disease caused by Sclerotinia homeocarpa.
Reduction of vigor and growth of competitor weeds like dandelion (Taraxacum officionale) and curly dock (Rumex crispus).
Use of bacteria in synthetic seed balls, liquid sprays, and controlled release fertilizer formulations for application to grass plants or seeds.
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