Research

We conduct the research by focusing on plant-microbe interactions, using genomic information, gene transformation techniques, and bio-imaging, as well as various molecular biological techniques in plants. In particular, we are currently studying on the following three research themes to gain pioneering knowledge on plant immunity and symbiosis with microorganisms by using our own experimental systems and tools.

Our research targets range from wild plants to herbaceous plants (orchid, Arabidopsis thaliana, legumes, tomato, etc.), according to the nature of research. We conduct research on pathogenic and symbiotic fungi, too. In order to promote vigorous research, we actively collaborate with many researchers, both inside and outside the university, in Japan and abroad. In applied research, we are collaborating with many private companies.

1. Recognition of fungi, induction of plant immunity and growth promotion by plants through chitin recognition

Chitin, a natural polysaccharide, is a major component of the fungus cell wall and has been shown to be involved in the recognition of fungi by plants. Chitin-treated plants show the induction of disease resistance (plant immunity) and growth promotion, suggesting that similar effects caused by beneficial fungi may be mediated through the chitin recognition. Based on these findings, we are conducting the research to decipher the mechanisms underlying plant immunity and growth promotion by chitin and beneficial fungi, as well as the sensing of fungi through chitin recognition at the molecular level.

2. Regulatory mechanisms underlying the mycorrhizal symbiosis associated with mycoheterotrophy in orchids

Plants are the only autotrophs that can live by synthesizing carbon sources (sugars) through photosynthesis and using them to produce energy. However, some plants, regardless of taxonomic group, have emerged during evolution as mycoheterotrophs, that take advantage of symbiotic relationship with mycorrhizal fungi, to live by depriving fungi of their carbon source. Orchids are known to have acquired a unique mycorrhizal symbiotic system associated with mycoheterotrophy in the early stages of growth after seed germination. We are studying various orchid species to decipher the regulatory mechanisms and evolution of mycorrhizal symbiosis involved in mycoheterotrophy at the molecular level.

3. Regulatory mechanisms and evolution of arbuscular mycorrhizal symbiosis

Arbuscular mycorrhizal fungi, which can establish the symbiotic relationship with more than 70% of terrestrial plants, receive the photosynthetic products in return for providing plants with phosphorus and nitrogen from the soil through symbiosis. They are also known to take different morphotypes in the roots depending on the taxonomic group of the partner plant. Since taxa in which mycoheterotrophs emerge form one of mycorrhizal morphotypes, Paris type, it’s thought that the formation of Paris-type mycorrhiza is involved in the evolution to mycoheterotrophs. However, the symbiosis with arbuscular mycorrhizal fungi in plants that form the Paris-type mycorrhiza is poorly understood. Hence, we are attempting to elucidate the regulatory mechanism underlying the mycorrhizal symbiosis at the molecular level using tomato (Solanaceae) and lisianthus (Gentianaceae), and are also conducting the research on the acquisition and evolution of mycoheterotrophy using Gentianaceous wild plants.