From molecular probes to novel agrochemicals: a journey through plant hormone research using modern plant science findings

Abstract My research journey began with the development of inhibitors targeting the photosynthetic electron transport chain, aiming for their application as herbicides. After a period of herbicide research at an agrochemical company, I joined RIKEN in 1991, where my primary focus shifted to developing plant hormone regulators. The research here initially aimed not only at applications for agricultural use, but also at applications for understanding fundamental plant biology. Forty years ago, compared to the present, the biological knowledge and chemical principles for designing biologically active compounds were insufficient. However, I have consistently pursued a biorational approach as much as possible. Along the way, I have also been fortunate to experience numerous moments of serendipity. In the initial stages of developing photosynthetic electron transport inhibitors, compound design was carried out based on 2D knowledge. Subsequently, we attempted structure-based design utilizing the three-dimensional structure of the target protein. However, such approaches were not yet efficient at the time. Today, with the remarkable progress in structural biology and AI-based target structure prediction, truly rational, structure-guided compound design is becoming increasingly feasible. Motivated by this progress, I have continued my research even after retiring from the University of Tokyo, now at Yokohama City University, where I remain engaged in the development of novel biorational bioactive compounds. My goal is to design and synthesize bioactive compounds that contribute to both plant science and agriculture, and I find great joy in engaging in such research.