Fungal volatile organic compound enhances plant s growth characteristics
Inventors
Dardick, Christopher D. • Janisiewicz, Wojciech J. • Liu, Zongrang • Li, Zhijian • Callahan, Ann M
Assignees
US Department of Agriculture USDA
Publication Number
US-11254907-B2
Publication Date
2022-02-22
Expiration Date
2039-03-19
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Abstract
A method of increasing east one growth characteristic of a plant comprising growing a Cladosporium sphaerospermum strain in or on a medium in a container, where a headspace of said C. sphaerospermum in said container is in fluid communication with a headspace of said plant, where said C. sphaerospermum produces at least one volatile organic compound (VOC), where said at least one VOC produced by said C. sphaerospermum causes the plant to have an increase in at least one growth characteristic when compared to the growth characteristic of a plant which has not been exposed to the VOC, and where said C. sphaerospermum comprises an ITS1/2 consensus amplicon of SEQ ID NO: 5 and an ITS3/4 consensus amplicon of SEQ ID NO: 6.
Core Innovation
This invention relates to a method of increasing at least one growth characteristic of a plant by exposing the plant to at least one volatile organic compound (VOC) produced by the fungus Cladosporium sphaerospermum. The method involves growing a strain of C. sphaerospermum in or on a medium in a container so that the headspace containing the fungus is in fluid communication with the headspace of the plant to be treated. The VOCs produced by C. sphaerospermum cause the plant to have an increase in at least one growth characteristic compared to an untreated plant.
The problem being solved arises from the limitations in current plant growth-promoting microbial products, which mostly require direct contact with the plant through soil inoculation, seed inoculation, or as endophytes. Such methods can be inefficient or have undesirable environmental releases. Additionally, microbial VOCs capable of promoting plant growth without direct contact have been limited in their effectiveness and practical application. There existed a need for identifying microorganisms, particularly strains of C. sphaerospermum, capable of emitting VOCs that effectively increase plant growth and/or yield through air space exposure without direct contact.
The innovation provides a method of enhancing plant growth characteristics using volatile organic compounds produced by specific strains of C. sphaerospermum characterized by their ITS1/2 and ITS3/4 consensus amplicon sequences. The VOCs induce increased growth characteristics including but not limited to growth rate, biomass, root and shoot development, stress tolerance, fruit yield, size, and quality. The fungus can be cultured on various growth media and positioned so its VOCs can permeate the plant's headspace or root environment, enabling growth stimulation without fungi physically contacting the plant. This approach improves plant growth and productivity while avoiding the downsides of conventional microbial inoculation methods.
Claims Coverage
The patent contains one independent claim focusing on a method of enhancing multiple plant growth characteristics by using Cladosporium sphaerospermum VOCs in fluid communication with a plant's headspace. The main inventive features from this claim include the fungal culture arrangement, selection of growth characteristics, applicable plant types, media types for culturing the fungus, exposure duration, and specific fungal strains.
Method of increasing multiple plant growth characteristics
A method including growing C. sphaerospermum strain on or in a medium within a container such that the fungus headspace is in fluid communication with the plant headspace, where VOCs produced by the fungus increase at least two growth characteristics of the plant compared to untreated plants.
Selection of growth characteristics enhanced by VOCs
The growth characteristics enhanced include a comprehensive group such as growth rate, biomass, plant height, branch and leaf metrics, stem and root features, stress tolerance, pigment production, metabolite accumulation, and various yield and quality parameters, including fruit, grain, and seed attributes.
Applicability to various plant types
The method is applicable to plants that are gymnosperms or angiosperms, including monocotyledons and dicotyledons.
Culturing media for C. sphaerospermum growth
C. sphaerospermum is cultured on media selected from Murashige and Skoog medium, potato dextrose agar, Czapek-DOX yeast agar, yeast extract agar, malt extract agar, or Hunter's medium.
Duration of plant exposure to VOCs
The plant is exposed to the VOCs produced by C. sphaerospermum for about one day to about thirty days.
Specific fungal strains used
The method employs C. sphaerospermum strains including Accession Nos. NRRL 67603, NRRL 8131, and NRRL 67749.
The claims collectively cover a method of enhancing at least two plant growth characteristics by exposing plants to VOCs produced by specific C. sphaerospermum strains grown in a container fluidly connected to the plant's headspace, specifying the growth characteristics influenced, the broad applicability to plant types, culturing media, exposure durations, and defined fungal strains.
Stated Advantages
Substantially increased plant growth characteristics including stem length, biomass, root development, and leaf size in treated plants relative to controls.
Accelerated plant growth leading to earlier flowering, fruit set, and harvest compared to untreated plants.
Sustained growth promotion effects in plants after cessation of VOC exposure and transfer to soil or open environments.
Improved root formation and development leading to enhanced transplantation success and acclimatization of tissue-cultured plants.
Effective stimulation of growth in a wide variety of plant species spanning monocots and dicots, including crops and ornamentals.
Documented Applications
Enhancement of growth characteristics such as biomass, height, leaf size, root development, and yield in tobacco plants.
Acceleration of flowering time and substantial increase in fruit yield and quality in cayenne pepper plants.
Promotion of seedling growth and biomass accumulation in switchgrass and wild strawberry species.
Improvement of in vitro root formation and successful acclimatization to soil in peach rootstock plants.
Growth promotion in various other plants including Amaranthus tricolor, basil, lettuce, endive, kale, arugula, and tomato through in vitro exposure to fungal VOCs.
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