Japanese Scientists Explore Interaction Between Rice Blast Fungi and Soil Microbes in Recent Study
Pyricularia oryzae or rice blast fungus poses a significant threat to rice crops as it can cause extensive damage and lead to substantial yield loss. Methods to control this pathogen involves a reliance on chemical fungicides, which can have detrimental environmental impacts and contribute to the development of resistant strains.
Researchers are exploring alternative strategies that leverage natural microbial interactions to promote plant health and manage diseases more sustainably.
A team of Japanese researchers, led by Tokyo University of Science (TUS) Department of Applied Biological Science Assistant Professor Furuyama Yuuki, aimed to investigate the relationship between P. oryzae and the beneficial soil bacterium Streptomyces griseus in their recent study.
The research team included Ms. Risa Sugiura, Prof. Kouji Kuramochi, Prof. Takashi Kamakura, and Dr. Takayuki Arazoe, all from TUS, as well as Dr. Takayuki Motoyama from the Institute of Physical and Chemical Research and Dr. Hiroyuki Osada from the Institute of Microbial Chemistry. The team’s study was published in the September 2024 edition of Environmental Microbiology Reports.
“While extensive research has been conducted on how rice blast fungi infect their host rice plants, many aspects of their life cycle remain poorly understood. Our study aims to shed light on the interactions between rice blast fungi and other microorganisms in the soil, exploring the crucial part of their life cycle beyond the infection process,” explains Dr. Furuyama.
The team conducted a series of experiments involving co-cultures of P. oryzae and S. griseus to investigate the interactions. They measured the pH changes in the growth medium and observed the effects on S. griseus growth under various conditions.
Findings revealed that the presence of P. oryzae significantly increased the pH of the medium and promoted the growth of S. griseus. Furthermore, the enhancement was independent of direct contact between the two microorganisms, suggesting that P. oryzae produced non-volatile alkaline compounds responsible for this effect.
The study also highlighted that other pathogenic fungi, namely Fusarium oxysporum and Cordyceps tenuipes, did not induce similar growth in S. griseus. Researchers ruled out ammonia as the compound responsible for pH increase, leading them to propose that polyamine produced by P. oryzae might be the active growth-inducing agent.
This discovery has significant implications for the development of sustainable agricultural practices. S. griseus has the ability to produce antibiotics, and this can suppress the growth of pathogenic microorganisms. P. oryzae promoting the growth of S. griseus suggests it may inadvertently create conditions that could be harnessed to control its own spread.
“Our findings suggest that S. griseus could be used as a biocontrol agent in rice fields, offering an alternative to chemical fungicides. If we can enhance the growth of S. griseus in rice paddies, we may be able to reduce the impact of rice blast in an environmentally friendly way,” stated Dr. Furuyama.
The study also offers valuable insights into the ecological role of P. oryzae, indicating that it may influence the composition and dynamics of microbial communities in the soil. The researchers propose that their findings could have wider implications of how pH modulation affects microbial interactions, paving the way for the development of innovative biocontrol strategies for managing other plant diseases as well.
Additionally, this study could revolutionize the way people approach disease management in rice crops, offering hope for a future that is less reliant on harmful chemical agents.
