Dr. Orsolya Kedves, researcher at SZTE’s Department of Biotechnology and Microbiology, is working with fellow researchers to develop a line of microbial plant conditioners tailored to the distinctive characteristics of different plants’ rhizospheres. The team hypothesizes that, under certain conditions, plant-specific microbial formulations may support plant growth and stress tolerance more effectively than products designed for general use.
Plant roots do far more than anchor plants in the soil: they release a wide range of organic compounds into their immediate surroundings. The quantity and composition of these compounds vary depending on plant species and variety, stage of development, and the surrounding soil and environmental conditions. These root-derived compounds, in turn, help shape the physical, chemical, and biological properties of the rhizosphere. They can influence the availability of certain nutrients as well as the composition and activity of the microbial communities associated with the roots.
The rhizosphere – the dynamic zone of soil shaped by plant roots – teems with complex communities of bacteria, fungi, and other microorganisms. Compounds released by the roots can provide vital nutrients for some of these microbes. In return, plant-associated microorganisms may help improve nutrient availability, support plant growth and stress tolerance, and suppress certain plant pathogens.
The project led by SZTE research fellow Dr. Orsolya Kedves explores how interactions between plants and microorganisms vary across species and varieties, with the long-term goal of developing microbial plant-conditioning products tailored for targeted use.
“More frequent droughts, heat waves, and increasingly extreme rainfall patterns may put the security of agricultural production at risk. At the same time, intensive land use and certain farming practices can have a damaging impact on soil health, biological activity, and microbial diversity. Environmentally friendly microbial products may help ease these pressures, but their effectiveness can vary significantly depending on the plant species, soil properties, and environmental conditions,” says Orsolya Kedves.
The project is based on the premise that carefully selected consortia of microorganisms isolated from a plant’s own rhizosphere may support the growth of that same species or variety particularly effectively. The researchers will investigate when – and to what extent – these plant-specific consortia can outperform microbial products formulated without reference to their plant-associated origin.
“We isolate and study microorganisms that occur naturally in the rhizosphere of a particular plant and are therefore likely to be well adapted to its distinctive microecological conditions. From the most promising strains, we create carefully designed consortia containing multiple microorganisms. Our goal is not simply to propagate the microbes already present around the roots, but to identify strains with genuine plant growth-promoting potential – those that may improve access to certain nutrients, successfully colonize the root zone, and help suppress specific plant pathogens,” the researcher explains.
Designing effective consortia begins with compatibility: the individual microorganisms must work together without suppressing one another’s growth or diminishing their beneficial traits. The selected bacteria and fungi can support plants through several complementary mechanisms. They may produce growth-regulating compounds, enzymes, and iron-binding molecules known as siderophores; mobilize key nutrients in the soil; and act directly or indirectly against certain plant pathogens.
A key innovation of the project lies in looking beyond microorganisms’ general plant growth-promoting properties. When designing the microbial consortia, the researchers also consider which plant species each microorganism is naturally associated with and how well it is adapted to the conditions of that plant’s rhizosphere. Unlike microbial products developed for broad use, the project takes a targeted approach, tailoring each formulation to a specific plant and its distinctive root environment.
“Our preliminary experiments provided a compelling basis for putting the plant-specific approach to the test under controlled conditions. We believe that formulations built around microorganisms selected specifically for a given plant may, under certain conditions, deliver greater effectiveness. Demonstrating this potential, however, will require further validation through laboratory, growth chamber, greenhouse, and field studies. Because plants actively shape the soil environment around their roots, this dynamic should be factored into the development of microbial products,” explains Orsolya Kedves.
At SZTE’s Department of Biotechnology and Microbiology, the Environmental Microbiology and Biological Control Research Group has spent years investigating the agricultural potential of microorganisms found in soil and plants. This extensive groundwork provided a solid foundation for the project: when the research began, the team already had access to more than one hundred microbial isolates collected from the rhizosphere.
The Szeged Microbiological Culture Collection includes microorganisms isolated from the rhizospheres of tomato, cucumber, and wheat, among other crops. The project is now expanding this resource by isolating new bacterial and fungal strains from the root zones of lettuce varieties, cabbage, pepper, tomato, and cucumber.
“We prepare serial dilutions from rhizosphere soil samples and inoculate selected dilutions onto carefully chosen culture media. The colonies that emerge are used to establish pure cultures, after which the bacterial and fungal strains are identified through molecular techniques and profiled in a series of functional assays,” says Orsolya Kedves, describing one of the project’s key laboratory processes.
Each strain is then assessed for its potential to promote plant growth, colonize roots, withstand environmental stress, inhibit plant pathogens, and improve the availability of selected nutrients.
“A large proportion of the phosphorus in soil is often bound in poorly soluble forms that plants cannot absorb directly or can access only in limited amounts. Certain bacteria and fungi may help unlock these reserves by producing organic acids, enzymes, and other metabolites, thereby increasing the phosphorus available to plants. Other microorganisms may enhance iron availability, support nitrogen supply, or stimulate root development,” the researcher notes.
The first microbial isolates have already been obtained, and the newly identified strains are now being analyzed at the molecular level and evaluated for their functional properties. Once the most promising candidates have been selected, the team will assess their compatibility and assemble them into multi-strain consortia.
“Once the consortia are ready, we will launch the plant trials under controlled conditions in growth chambers and greenhouses, followed by field studies to assess the formulations in practice. Trials with autumn-sown crops – including winter wheat, winter barley, and rapeseed – may begin in the fall, while experiments involving spring-sown and transplanted plants may take place in the spring. Growth chambers, meanwhile, enable us to carry out controlled experiments year-round,” adds Orsolya Kedves.
The researchers will evaluate the treatments across a broad range of indicators, including germination, biomass production, root and shoot development, nutrient uptake, stress tolerance, and overall plant health. While controlled trials will provide essential insights, field experiments will be crucial in determining whether the microbial consortia can produce reliable, reproducible results under varying soil and weather conditions.
The project is mentored by Prof. Dr. Csaba Vágvölgyi and Dr. László Kredics. The microbiological studies involve Dr. Henrietta Allaga, research fellow, and András Varga, assistant research fellow, also from SZTE’s Department of Biotechnology and Microbiology. The plant trials are supported by Dr. Ingrid Melinda Gyalai and Flórián Kovács, assistant professors at the Institute of Plant Sciences and Environmental Protection within SZTE’s Faculty of Agriculture. Students completing their theses in this field are also actively involved in the research.
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SZTE TTC Zrt., the University of Szeged’s technology-transfer company, secured funding for project 2024-2.1.3-POC-2025-00005 through the Proof of Concept call 2024-2.1.3-POC, launched by the Ministry of Culture and Innovation and administered by the National Research, Development and Innovation Office.
Under the program, SZTE TTC Zrt. awarded HUF 19,999,999 in non-repayable funding on May 7, 2026, to the University of Szeged project “Development and investigation of the mechanisms of action of plant-specific rhizosphere-derived microbial consortia,” registered under project ID TTCPOC006/2025. The National Research, Development and Innovation Fund provides 90 percent of the financing, while SZTE TTC Zrt. contributes the remaining 10 percent from its own resources. Launched on May 1, 2026, the project’s research program is expected to be carried out over a 12-month period.
Source: SZTEinfo
Feature photo: Dr. Orsolya Kedves
