Division of Plant Sciences

Plant Symbiosis Research Unit

How do plants establish symbiosis with rhizobia and mycorrhizae?

 We are investigating symbiosis between plants and beneficial soil microbes. Legumes such as soybean establish symbiosis with soil bacteria - rhizobia. Rhizobia can fix nitrogen in the air into ammonium which is delivered to host plants. In turn, plants provide rhizobia carbon compounds that are made by photosynthesis. Most land plants, including major crops such as rice and soybean, establish symbiosis with soil fungi - mycorrhizae. Mycorrhizae absorb water and nutrients such as phosphorus and deliver them to host plants.
 Our research focuses on the molecular genetic mechanisms by which plants establish symbiosis with rhizobia and mycorrhizae. As a result, we can improve efficiency of symbiosis for agriculture. Much of current agriculture is highly dependent on chemical fertilizers which are produced from natural gas, phosphate rock, etc. that will be scarce in the future. By effective utilization of symbiosis between plants and soil microbes, we can realize low-input sustainable agriculture.

Invasion of rhizobia (green) in plant cells (red)

The arbuscule

The arbuscule (blue) is the structure where mycorrhizae exchange nutrients with plant cells.