Kumamoto University

Nagoya University

Niigata University

Miyazaki University

The University of Tokyo Graduate School of Science

Summary of Presentations

A research group led by Director Shinichiro Sawa and Postdoctoral Associate Professor Satoru Nakagami of the International Research Center for Bio-Environmental and Agricultural Sciences, Graduate School of Advanced Sciences, Kumamoto University, Professor Tetsuya Higashiyama of the Graduate School of Science, The University of Tokyo, Project Associate Professor Yoshikatsu Sato of Nagoya University, Project Associate Professor Lecturer Masataka Nodaguchi, Lecturer Tatsuhiko Kondo, Associate Professor Takanori Ida of Miyazaki University, Associate Professor Akira Okamoto of Niigata University, and other researchers The group discovered, for the first time in the world, that one part of the parasitic mechanism of nematodes infecting plants is peptide hormone hijacking in plants. Agricultural damage caused by nematodes amounts to several tens of trillions of yen annually. Until now, however, the only way to eliminate nematodes has been to exterminate the nematodes themselves, and the specific substances that are the target of extermination have not yet been elucidated. With this achievement, the target substances have been clarified, and it is expected that a new peptide-based pest control method will be developed. Peptide-based agricultural technology is currently attracting attention, and we believe that this substance will be a catalyst for the development of such technology in the control of plant-infecting nematodes.

The nematode (catlepis nematode) is a root parasite that forms cobs that deprive plants of nutrients and kill crops. Using the model plant Arabidopsis thaliana, we found that when nematodes form cobs on roots, they use Arabidopsis peptide hormones to force the transfer of sugars produced by photosynthesis from the leaves to the roots. Normally, the sugar transport signal to the roots is not active. When roots are infected by nematodes, the nematodes first induce sugar transporters in the aboveground vascular bundles by activating CLE peptide hormone, the carrier of the transport signal. Sugars are then transported to the roots. In other words, nematodes hijack CLE peptide hormone transduction in plants to obtain the energy (sugar) needed for cob formation. In the future, we plan to analyze the details of the mechanism, including how the nematodes activate the CLE gene.

Currently, soil fumigant application is the most effective method of killing nematodes in the soil, but due to the burden on farmers and environmental impact, there is a need for control methods that do not rely on fumigants. With this achievement, we plan to synthesize a substance (antagonist) that competes with the CLE peptide and binds to its receptor and spread it on the soil to suppress damage caused by root-knots, which we plan to attempt. We also plan to breed crops that block this mechanism to produce nematode-resistant crops. We are confident that our results will lead to innovations in the field of agriculture.

Our results are expected to contribute not only to our understanding of the interactions between animals and plants, but also to the agricultural field by increasing crop yields and stress tolerance.

The results of this research were published in the scientific journal " Science Advances " on June 2, 2023.

Figure: Analysis system for root mass formation using sweet potato root-knot and Arabidopsis thaliana.
(A) Photograph of a sweet potato root nodule stained with a red reagent. The red linear shape is a pre-growing centromere and the gourd-shaped one is a growing centromere. The white objects are Arabidopsis roots and rootlets.
(B, C) Assay system using transparent agar medium. Root nodule formation can be easily observed.

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