Hattori Yoko, Nagai Keisuke, Furukawa Shizuka, Song Xian-Jun, Kawano Ritsuko, Sakakibara Hitoshi, Wu Jianzhong, Matsumoto Takashi, Yoshimura Atsushi, Kitano Hidemi, Matsuoka Makoto, Mori Hitoshi, Ashikari Motoyuki
Bioscience and Biotechnology Center, Nagoya University, Nagoya 464-8601, Japan.
Nature. 2009 Aug 20;460(7258):1026-30. doi: 10.1038/nature08258.
Living organisms must acquire new biological functions to adapt to changing and hostile environments. Deepwater rice has evolved and adapted to flooding by acquiring the ability to significantly elongate its internodes, which have hollow structures and function as snorkels to allow gas exchange with the atmosphere, and thus prevent drowning. Many physiological studies have shown that the phytohormones ethylene, gibberellin and abscisic acid are involved in this response, but the gene(s) responsible for this trait has not been identified. Here we show the molecular mechanism of deepwater response through the identification of the genes SNORKEL1 and SNORKEL2, which trigger deepwater response by encoding ethylene response factors involved in ethylene signalling. Under deepwater conditions, ethylene accumulates in the plant and induces expression of these two genes. The products of SNORKEL1 and SNORKEL2 then trigger remarkable internode elongation via gibberellin. We also demonstrate that the introduction of three quantitative trait loci from deepwater rice into non-deepwater rice enabled the latter to become deepwater rice. This discovery will contribute to rice breeding in lowland areas that are frequently flooded during the rainy season.
生物必须获得新的生物学功能以适应不断变化的恶劣环境。深水水稻通过获得显著伸长节间的能力而进化并适应了水淹环境，其节间具有中空结构，起到通气管的作用，可与大气进行气体交换，从而防止植株被淹死。许多生理学研究表明，植物激素乙烯、赤霉素和脱落酸参与了这一反应，但负责该性状的基因尚未被鉴定出来。在此，我们通过鉴定基因SNORKEL1和SNORKEL2揭示了深水反应的分子机制，这两个基因通过编码参与乙烯信号传导的乙烯反应因子来触发深水反应。在深水条件下，乙烯在植物体内积累并诱导这两个基因的表达。然后，SNORKEL1和SNORKEL2的产物通过赤霉素触发节间显著伸长。我们还证明，将来自深水水稻的三个数量性状基因座导入非深水水稻，能使后者变成深水水稻。这一发现将有助于雨季经常被水淹的低地地区的水稻育种。
