Graduate School of Agricultural and Life Sciences, The University of Tokyo

Creating new crops by correctly understanding metabolic functions

When global food issues, climate change, and environmental destruction are considered, increase in yield and sustainability will be required in future crop productions. Since arable land as well as petroleum and mineral resources are limited, it is necessary to produce enough crops to feed the entire human population on the limited arable land, while minimizing the use of chemical fertilizers and making full (waste-free) use of the harvest. We at the Laboratory of Crop Science are focusing on the diverse metabolic functions of crops to address these issues. We do not limit our research to specific crops, but are currently using rice, soybeans, and sweet potatoes to identify genes and environmental factors involved in the metabolism of starch and sucrose, which are the main products of photosynthesis, as well as the metabolism of compounds containing nitrogen, phosphorus, and sulfur. Metabolic pathways that are key to production vary depending on crop species as the crops differ in their morphology, physiology, and harvestable parts, as well as in the substances (starch, protein, lipids, etc.) stored in those parts. In addition, metabolic functions vary depending on the part of the crop (leaves, stems, roots, etc.). Therefore, it is important to correctly understand the metabolic functions of the target crop species in order to develop new varieties and cultivation methods that improve yield, fertilizer utilization efficiency, or environmental stress tolerance. In addition, we are conducting research aimed at improving the quality of harvestable parts (e.g., seeds and tubers) and finding new uses for other parts (e.g., stems and leaves) by utilizing the knowledge we have gained about metabolic functions.

Seeds sown in the field bear fruit in the laboratory!

The Laboratory of Crop Science aims to achieve“Green Transformation (GX)” by setting two major goals: 1) stable and sustainable crop production, and 2) multi-purpose use of crops. Basic research methods include cultivating diverse varieties and genetic resources in fields and greenhouses, and conduct comprehensive analysis on the formation processes of harvestable parts and the accumulation processes of storage substances using crop physiological methods (biomass production, yield components, photosynthetic characteristics, ionome, etc.), biochemical methods (enzyme activity, metabolome, etc.), and molecular biological methods (transcriptome, genetic transformation). We respect students' independence in how they conduct their daily research (time spent in the lab, experiment schedules, etc.). They are also free to take part in club activities and part-time jobs. On the other hand, field work (such as sowing, transplanting, and sampling) and processing multiple samples are carried out cooperatively by everyone, so teamwork and communication are also important. 【Recent Theses】
Generation and Evaluation of High-sugar-stem rice plants using agpl1 loss-of-function mutants (Master's thesis)
Physiological and biochemical studies on the mother tuber enargement in sweet potato (Master's thesis)
Studies on the roles of vacuolar invertase genes in sugar metabolism of rice and sorghum (doctoral thesis)
Physiological studies on the inter-varietal differences in the ripening characteristics of high-yielding rice varieties (doctoral thesis)
【Career paths after graduation】
Government agencies (Ministry of Agriculture, Forestry and Fisheries, local governments), research and educational institutions, seed companies, food manufacturers, agricultural machinery manufacturers, trading companies, financial institutions, etc.

We study metabolic functions in all crop species.

The major goals of the Laboratory of Crop Science are aligned with SDGs 2: Zero Hunger, 12: Responsible Consumption and Production, and 13: Climate Action. In addition, in response to the goal of the domestic policy “Green Food System Strategy” to “improve crop yields while ensuring sustainability”, we are conducting research aimed at reducing resource and labor use in crop production. Our strength lies in our extensive knowledge and experience in analyzing the different metabolic functions of each crop species and parts, enabling us to conduct research tailored to the target crop and its intended use. Through the analysis of crop metabolic functions, we identify metabolic pathways, enzymes, and genes that are key to biomass production and yield formation. We then apply the knowledge gained to develop new varieties and cultivation methods. For example, we identify enzymes and genes involved in the absorption, assimilation, and metabolism of fertilizer components in the soil, and we plan to use the knowledge gained to improve fertilizer utilization efficiency. In addition, we are working on new ways to utilize the unused parts of crops with the aim of minimizing waste. For example, we are developing new rice varieties that can be used for food, feed (or bioethanol) by modifying the sugar composition of the stems using sugar metabolism-related genes that are specifically expressed in rice stems. Our current research focuses on food crops and feed crops, but have also worked with aromatic crops in the past and have an interest in specialty crops (secondary metabolites).