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

Search for genes that determine crop shape and their application

Most of the plant-based foods you eat at home are made from crops that have been improved through “breeding”. The history of breeding dates back more than 10,000 years, and some current crops are believed to have been bred for that long. There are various traits that have been improved through breeding, but the most important one is the“shape”. For example, the Green Revolution's improvement of crop height through morphological traits dramatically increased global food production and contributed greatly to overcoming the food crisis at that time. The main focus of my research is to clarify the genetic mechanisms that determine this“shape”. We have studied genes related to various morphological traits using rice as the research material. For example, we have identified genes that control the number of leaves on the rice plant, genes that determine the dorsoventrality (front and back) of the leaves, and genes that change the phyllotaxis (the regular pattern of leaf arrangement). In addition, we are accumulating genome-wide genetic information to comprehensively understand which genes are active where during the formation of embryos and leaves. Based on this information, we conduct research using genome editing and other technologies to analyze the functions of genes related to form at the molecular level, with the aim of elucidating the basic principles that determine the form of plants and crops. In the future, we would also like to work on developing new breeding materials by improving the agricultural traits related to shape.

Learning morphogenesis and genetics using the rice plant as material.

In the undergraduate program, I teach“Plant Molecular Breeding”, providing students with the fundamental knowledge necessary for breeding using molecular genetic techniques and an overview of the current state of molecular breeding. After being assigned to a laboratory, undergraduate and graduate students are mainly assigned to research topics related to genes involved in the morphogenesis and developmental processes of rice. Recent specific research themes include analysis of genes involved in the control of the plastochron in rice, analysis of genes involved in leaf morphogenesis in rice, exploration of new genes involved in the development of rice leaves, and analysis of genes involved in the superhydrophobicity of rice leaves. In pursuing these research themes, we employ basic molecular genetic techniques and morphological techniques, as well as genome editing technology, comprehensive gene expression analysis, cell-level expression analysis, imaging using fluorescent proteins, electron microscopy, X-ray CT analysis, and other technologies. In addition to laboratory research, we also conduct field research, including screening of mutants and trait surveys at the Institute for Sustainable Agroecosystem Services (Tanashi Farm) and crossbreeding experiments in fields. In our daily lab research, we aim to learn the basics of genetics and logical thinking through seminars and one-on-one discussions. Our graduates are now working in a variety of fields, including government agencies, food companies, and universities.

Discovering new useful traits through research on the genetics of rice

We analyze the functions of genes related to rice morphology. There are various morphological characteristics of rice. In particular, genes related to the cultivation characteristics and yield of rice have the potential to add new agriculturally useful traits to crops through genetic modification. For example, we have identified a gene that controls leaf length (cell division in leaves) in rice, and it has been shown that strongly expressing this gene in seeds results in larger seeds. In addition, we have identified a gene that controls leaf differentiation speed. This gene encodes an enzyme involved in the biosynthesis of an unknown compound, and the discovery of this compound is expected to have a significant impact on growth control not only in rice but also in various other plants. If you are interested in isolating unknown useful substances from plants, we can provide you with a variety of materials. Although slightly different from the shape of plants, we are also conducting research on the water repellency of plants using rice. Rice, like the lotus plant, is a plant with extremely high water repellency, or“superhydrophobicity”. To achieve superhydrophobicity, it is important to have a micro-irregular surface structure and a hydrophobic substance (wax), and we have identified the genes involved in each of these. Through the knowledge gained from this research, it may be possible in the future to control the water repellency of various substances and modify the components and content of rice wax through molecular breeding.