In the world of agriculture, rice is a staple food for greater than half of the world's population, making its cultivation critical to food security. However, rice blast fungus (syn.) is a major threat to rice crops, causing widespread damage and substantial yield loss. Traditional methods of controlling this pathogen often depend on chemical fungicides, which may damage the environment and contribute to the event of resistant strains. Therefore, researchers are increasingly on the lookout for alternative strategies that make the most of natural microbial interactions to advertise plant health and manage diseases more sustainably.
In a recent study led by Assistant Professor Yuki Foruyama of the Department of Applied Biological Science at Tokyo University of Science (TUS), a team of researchers aimed to analyze the connection between helpful soil bacteria and The research team included Ms. Risa Sugiura, Prof. Koji Kuramuchi, Prof. Takashi Kamakura, and Dr. Takayuki Arazu, all from TUS, in addition to Dr. Takayuki Motoyama and Dr. Hiroyuki Osada from the Institute of Physical and Chemical Research. Institute of Microbial Chemistry. Their study was published in Environmental Microbiology Reports on September 23, 2024.
“Although there has been extensive research on how rice blast fungi affect their host rice plants, many aspects of their life cycle are poorly understood. Our study The goal is to shed light on the interactions between rice blast fungi and other microorganisms in the soil, an important part of their life cycle beyond the infection process,” explains Dr. Furuyama. To investigate these interactions, the team conducted a series of experiments involving cocultures of P. oryzae and S. griseus. They measured the pH changes in the expansion medium and observed the results on the expansion of S. gracis under different conditions.
Their results showed that the presence of P. oryzae significantly increased the pH of the medium, which, in turn, promoted the expansion of S. griseus. Notably, this increase was independent of direct contact between the 2 microorganisms, suggesting that P. oryzae produced nonvolatile alkaline compounds accountable for this effect.
The study also highlighted that other pathogenic fungi, resembling Fusarium oxysporum and Cordyceps tenuipes, didn't induce similar growth in S. griseus, indicating that the observed interaction was specific to P. oryzae. is Additionally, the researchers ruled out ammonia because the compound accountable for the pH increase, leading them to suggest that the polyamine produced by P. oryzae often is the lively growth-promoting agent. is
The discovery of this unique microbial interaction has vital implications for the event of sustainable agricultural practices. S. griseus is thought for its ability to provide antibiotics, which may inhibit the expansion of pathogenic microorganisms. By promoting the expansion of S. griseus, P. oryzae may inadvertently create conditions that could be used to manage its own spread. “Our results suggest that S. griseus can be used as a biocontrol agent in rice fields, offering an alternative to chemical fungicides,” says Dr. Foruyama. “If we can increase the growth of S. griseus in rice paddies, we may be able to reduce the effects of rice blast in an environmentally friendly way,” adds Dr. Foruyama.
Additionally, the study offers helpful insight into the ecological role of P. oryzae, showing that this fungus can affect the structure and dynamics of microbial communities in soil. The researchers suggest that their findings can have broader implications for our understanding of how pH modulation affects microbial interactions, resulting in the event of modern biocontrol strategies for managing other plant diseases. The path is paved.
With this vital discovery, the team has taken a very important step towards more sustainable agricultural practices. The ability to harness the facility of microbial interactions to combat rice blast could revolutionize the way in which we approach disease management in rice crops, promising a future with less reliance on harmful chemical agents. does