Newswise — A RUDN University biologist and colleagues from Iran have found bacteria that can become a potential biological drug against a pest fungus that infects rice. Unlike chemical fungicides, such a bio-agent is harmless to the environment and does not lead to the formation of biological resistance. The results are published in Agronomy.
The fungus Rhizoctonia solani causes rot diseases in plants, including rice. This leads to crop losses. Fungicides are used to control the pathogen, but this is harmful to the environment. In addition, due to too frequent use, the fungus develops resistance to drugs. Therefore, it is necessary to look for new, safer and more reliable ways to control the pest. One of the possible solutions is bioagents that inhibit the growth and reproduction of dangerous fungi. A RUDN University biologist with colleagues from Iran found that Actinomycetes bacteria are suitable for the destruction of Rhizoctonia solani.
“The use of chemical fungicides remains the main method of controlling plant diseases. However, this not only pollutes the environment, but also leads to the resistance of pathogens. It is important to develop methods that combine the use of chemicals and biological agents. This will allow us to successfully overcome the resistance of pathogens to chemicals,” said Meisam Zargar, PhD, Associate Professor of the Agrobiotechnological Department of RUDN University.
Bacteria of the Actinomycetes order live mainly in the soil and decompose substrates. These bacteria produce a number of substances with antibiotic properties - they can destroy the cell walls of microorganisms. That is why PFUR biologists have chosen them as potential bioagents against Rhizoctonia solani. The scientists studied 30 Actinomycete isolates. Three of them showed high activity against the pathogenic fungus Rhizoctonia solani - they destroyed the most pest in the experiment in a Petri dish. The best result is the complete elimination of the fungus with a diameter of 27 mm on the fifth day of the experiment.
The top three isolates were tested in the rice seed experiment. After treatment with Actinomycetes, the sprouts are taller - 8.5 cm versus 3 cm for infected but not treated seeds. The underground part of the sprout also becomes stronger. A root about 4.5 cm long is obtained from a seed treated with Actinomycetes, and a little more than 1 cm from an untreated seed. An adult plant grown from a treated seed showed no signs of disease.
“Actinomycetes produce several antibiotics and enzymes that break down cell walls. Therefore, it is important to pay more attention to them in terms of agriculture. Our results provide an opportunity to develop biological agents against Rhizoctonia solani. This can be a valuable starting point for other researchers who want to implement biocontrol technologies and promote sustainable agriculture,” said Meisam Zargar, PhD, Associate Professor of the Agrobiotechnological Department of RUDN University.
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