Institute of Agrobiological Sciences, NARO

Exploring the mystery of "Snow mold disease" that molds the crop under snow

- Developed an experimental system to investigate the resistance mechanisms of plants to snow mold fungi -

Snow mold is a serious disease that withers wheat and grasses. National Agricultural Food Research Organization(NARO), in collaboration with Hokkaido University and The Hachinohe Institute of Technology, has first identified the snow mold fungi that infect the model plant Arabidopsis (Arabidopsis thaliana) and developed an experimental system to evaluate the resistance of plants to snow mold fungi using Arabidopsis. It is expected that this experimental system will further elucidate molecular mechanisms of plants resistance to snow mold infection, which has not been known so far. Based on this knowledge, the development of varieties of wheat, barley, grasses, etc. with strong snow mold resistance as well as snow mold control technology is expected to progress.


In the areas where crops are exposed to snow for long periods such as Hokkaido and Hokuriku, a disease called "snow mold" occurs under snow. Snow mold is prominently observed mainly in wheat, barley, and pasture, and rotten leaves appear in these plants as spring snow melts. To control snow mold, it is necessary to spray agricultural chemicals just before the start of continuous snow cover. However, it is not easy to determine when to spray these chemicals. Therefore, it is strongly required to breed varieties resistant to snow mold. However, as the disease occurs under snow, the manner of infection by snow mold fungi, which is the basis for breeding varieties, and the mechanism of plant resistance has not been fully elucidated.

Therefore, as a first step to clarify the mechanism of the resistance, we identified snow mold fungi that infect the experimental plant, Arabidopsis and developed an experimental system useful to evaluate the resistance of plants to snow mold fungi using the model plant. Also, using this developed experimental system, it was clarified that the cold acclimation improves the resistance to snow mold fungi. It was also revealed that the phytohormone jasmonic acid enhances the resistance, and another phytohormone ethylene has a reverse effect to suppress it.

Since Arabidopsis has a variety of research resources necessary for experiments such as mutant strains, it is expected that the mechanism of resistance will be revealed by using this experimental system in the future. It is also expected that the breeding for varieties with snow mold resistance in wheat, barley, grasses and so on will be promoted.

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Published paper

Kuwabara C* , Sasaki K*, Umeki N, Hoshino T, Saburi W, Matsui H, Imai R. A model system for studying plant-microbe interactions under snow. Plant Physiology, Volume 185, Issue 4, 2021, Pages 1489-1494,
* Co-first authors