Plant Reproductive Design

Associate Professor: MIZUTA Yoko
Labs HP: https://mizutayoko.wixsite.com/plant-reprod-design/en

Outline of Research and Education

Our research aims to understand how flowering plants produce offspring. We focus on pollen development, cell fate determination, and the acquisition of fertility during pollen development, using our unique live imaging and genetic engineering approaches. This work is significant not only for elucidating the fundamental principles governing the “design of life” but also for addressing global challenges, such as the food crisis and climate change. We believe that our interdisciplinary research will contribute to significant breakthroughs.

Major Research Topics

Regulatory mechanisms of pollen development and differentiation

Pollen is produced by the asymmetric division of a microspore, which differentiates into a large vegetative cell and a small generative cell (Fig. 1). If symmetric division occurs due to environmental stress, pollen does not have a generative cell, demonstrating that asymmetric division is essential for successful fertilization. We use live imaging and gene introduction, along with genetic and omics analyses, to unravel the regulatory mechanisms of pollen development and differentiation. We aim to understand the process by which two distinct types of cells emerge from a single cell, as well as the molecular mechanisms by which cells acquire fertilization capabilities.

Molecular mechanism of polyspermy block

In Arabidopsis, pollen germinates a pollen tube after landing on the pistil. Interestingly, each ovule attracts only one pollen tube and rejects the others, demonstrating “one-to-one” pollen tube guidance (Fig. 2). This is known as the polyspermy block, which is regulated by some receptors and small peptides as ligands. By analyzing these factors and cellular dynamics, we can uncover the sophisticated reproductive system that flowering plants have evolved to ensure the production of more offspring.

"Design" of plant reproductive engineering

The genes involved in pollen development and fertilization can be rapidly studied using transient gene introduction (Fig. 3). Each target pollen grain was analyzed at the single-cell level using live-cell micromanipulation and laser disruption. These target pollens can also be used for pollination. Our goal is to develop innovative plant reproductive technologies based on the regulation of pollen development and fertilization.