Welcome to the Kawashima Laboratory!

Although many factors involved in seed development and seed sizes/numbers have been identified, the precise mechanisms of how plants accomplish seed development and control these seed traits are largely unknown.  Using the confocal microscopy real-time live-cell imaging approach, we are investigating the molecular mechanisms, cellular dynamics, and evolution of land plant sexual reproduction, especially focusing on stages from fertilization to early seed/embryo development. 

New publication in Nature Communications about plant sperm evolution!

How new cell types evolve remains a major question in biology. Across multi-cellular organisms, reproduction generally occurs via small, motile sperm that fertilize large immotile eggs. However, the widely varied morphologies of sperm makes one wonder whether this cell type evolved from a single common ancestor or if sperm identity was defined by distinct events in separate group of organisms.

In work published today in Nature Communications, a collaborative project found that a single molecular event which occurred 700 million years ago was responsible for the evolution of sperm in all land plants.

F-actin in the Arabidopsis zygote

Cyan: F-actin in the zygote, Yellos: zygote nucleus, Magenta: cell structures (Kimata et al., PNAS, 2017)

F-actin in the Arabidopsis central cell

Cyan: F-actin in the central cell, Yellow: egg nucleus, Magenta: synergid cells
(Kawashima et al., eLife, 2014; Nikon Small World, HM, 2014)

USDA supports a student for summer research in my laboratory (2018-2021)