DATE2026.01.28 #Press Releases
Deciphering Gene Expression in Living Cycad Sperm 130 Years After Their Discovery
-Swimming sperm formed within pollen tubes reveal an intermediate stage in the evolution of fertilization mechanisms in land plants-
Summary
A research team led by graduate student Yukiho Toyama, Professor Tetsuya Higashiyama, and Assistant Professor Satohiro Okuda at the Graduate School of Science, the University of Tokyo, together with Professor Takamasa Suzuki of Chubu University, has elucidated the dynamics and evolutionary characteristics of gene expression in fertilization-related cells of cycads, gymnosperms that reproduce using motile sperm.
In this study, the researchers identified the fertilization period of cycads at multiple locations ranging from Japan’s southwestern islands to the Kanto region. By establishing a method to stably isolate living sperm cells, they enabled comprehensive gene expression analyses of cycad fertilization-related cells. Although cycad sperm were first discovered in Japan approximately 130 years ago and have since been studied primarily through morphological analyses, this research represents the first in-depth investigation of gene expression in these cells. The findings are expected to make a significant contribution to our understanding of the evolutionary history of fertilization mechanisms in land plants.
Figure：Pollen tubes in cycad ovules, sperm cells within pollen tubes, and living sperm exhibiting flagellar motility
Journals
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Journal name Proceedings of the National Academy of SciencesTitle of paper