| 要旨トップ | 目次 | | 日本生態学会第73回全国大会 (2026年3月、京都) 講演要旨 ESJ73 Abstract

一般講演（口頭発表） J03-02 （Oral presentation）

#### Decoding mast seeding: Seasonal gene expression revealed new molecular pathways to understand forest tree reproduction【E】

*Valentin JOURNE（Kyushu University）, Yuka IKEZAKI（Kyushu University）, Hideki HIRAKAWA（Kyushu University）, Makoto KASHIMA（Toho University）, Atsushi J. NAGANO（Nagoya University）, Takeshi TORIMARU（Tottori University）, Nobuhiro TOMARU（Nagoya University）, Shin-Ichi MIYAZAWA（FFPRI）, Nobutoshi YAMAGUCHI（NAIST）, Qingmin HAN（FFPRI）, Akiko SATAKE（Kyushu University）

Perennial plants reproduce through a high interannual variability in seed production, with irregular years of high reproductive output—a phenomenon known as mast seeding or masting. While mast seeding is linked to fluctuations in weather and resource availability, the molecular mechanisms that trigger or suppress flower production remain poorly understood. Here, we explored molecular basis of tree flowering, and relationships between gene expression and environment. We collected a unique nine-year dataset of seasonal gene expression from leaf samples of Japanese beech (Fagus crenata) at Mt. Naeba in central Japan. From a total of 40,000 genes, we identified 20 genes whose expression levels were associated with heavy flowering, including key floral regulators and additional genes related to sulfur deficiency. Nitrogen has previously been shown to be a key trigger of flowering in F. crenata. We found that increased nitrogen availability elevates sulfur demand, and when sulfur supply fails to keep pace, plants experience sulfur limitation and activate a low-sulfur response that suppresses flowering. These findings provide new insights into how seasonal molecular regulation of tree flowering shapes reproductive phenology and its relationship with resource availability.

日本生態学会