Phytochrome dependent quantitative control of Hd3a transcription is the basis of the night break effect in rice flowering

Ryo Ishikawa, Tomoko Shinomura, Makoto Takano, Ko Shimamoto
Genes & Genetic Systems, 2009, 84(2): 179-184     追溯原文......本站官方QQ群:62473826

A short exposure to light during relative night (night break; NB) delays flowering in the short day plant rice. NB acts by downregulating Heading date 3a (Hd3a) expression. Because phytochrome B mutants do not respond to NB and their flowering time is not affected even under NB conditions, phyB is required for the suppression of Hd3a expression. The effect of NB is quantitatively controlled by light quality and by either light intensity or duration. However, the molecular mechanisms that regulate these interactions are poorly understood. Here, we examine the roles of phytochromes in the regulation of Hd3a transcription under NB conditions using monochromatic red, far-red and blue light. Red and blue light downregulated Hd3a expression, but far-red light NB did not. The effect of red light NB on Hd3a is dependent on photon fluence and is restored by subsequent far-red light irradiation. Our results suggest that quantitative effect of light on flowering in rice NB is mediated by the regulation of Hd3a transcription by phyB.

  成花素基因;抽穗期基因;生育期基因;光周期敏感基因;感光基因 Hd3a; FT