OHWADA Takuji Professor

ThemeUtilization of plant symbiotic bacteria for food production

My DreamStudy on the plant health through the symbiotic relationship between microbes and the host plants


Research Department/Department of Life and Food Sciences/Division of Food Science/Section of Biomolecular Structure and Function
Faculty (Unit)Food Science Program
Field Applied microbiology
Keyword plant symbiotic bacteria, endophyte, urethane-degrading bacteria


Microbes that inhabit plant tissues symbiotically are called endophytes. The effects of endophytes isolated or selected from crops that are representative of Tokachi (e.g., potatoes and beets) on the promotion of plant growth, the improvement of environmental adaptability, and the mechanism of infection and symbiosis in plants are studied in order to use endophytes to improve agricultural productivity. In recent research, we've found that the localization of plant tissues varies by strains (systems), and that mixed inoculation with strains without antagonizing localization (strains that can coexist or be segregated) improves the inoculation effect in a synergistic manner. We've also found excellent plant growth promotion and biocontrol factors in useful endophytes isolated or selected from beets (Fig. 3). Bacteroids have the ability to reduce (fix) nitrogen in the atmosphere to ammonia by forming bumps (root nodules) in the roots of legume plants, and they're very important to farming as soil bacteria that provide microbial nitrogen fertilization (Fig. 4). Through exhaustive analyses of root nodule gene expression in the symbiotic process, we've discovered extensive gene regions related to symbiosis, analyzed their expression, and found that the expression of one such region (the Type 3 secretion system) is controlled by temperature and genes (nodD2). We've also found that the symbiotic system of soybeans and their root nodules is optimized when the concentration of a signal substance of soybean origin (genistein) that is found in root nodules and that is cytotoxic, is adjusted by the control of chemical discharge pumps, and we presented a new paradigm that isn't found in the conventional mechanism of symbiosis. We've also succeeded in developing and commercializing a new material (NPORUS) with excellent practical properties that is made from urethane, and we've been engaged in research on its application to efficient agricultural production.

Fig. 3 Micrograph (SEM) of a useful symbiotic microbe infected to the root of chinese cabbage
Fig. 4 Nodules formed by root nodule bacteria harboring a reporter gene (gus) in the soybean root (nodules formed by the inoculant are identified)

List of current research topics

  • Study on adaptation of plants to environmental stress and enhancement of their functional compounds by plant symbiotic bacteria.
  • Development of efficient microbial decomposition technology for urethane and its application to agricultural production
  • Study on effects of microbial materials (biological control of plant diseases, etc.)
Related industries agricultural production, biorecycle
Affiliated academic society The Japanese Society of Plant Microbe Interactions, The Japan Society for Bioscience, Biotechnology, and Agrochemistry, The Japanese Society of Soil Science and Plant Nutrition, The Japanese Society of Soil Microbiology, The Society for Biotechnology, Japan
Academic degree Ph.D, Agriculture
Self introduction

I was born in Kyoto, but I've lived longer in Hokkaido longer—ever since I moved here to enter university. For my graduation thesis, I conducted research on conversion fermentation, which is the process whereby a target amino acid is fermented or produced through the combination of different microbes.
Since then, microbes have been the ongoing focus of my research. Since when I came to Obihiro, I have been engaged in the symbiosis between microbes and plants I'm very fond of Tokachi and Obihiro, since I love nature and hot springs.

Room addressGeneral Research Building 3
Room number407
Mail address taku atmark obihiro.ac.jp