Role of RPT2 in Leaf Positioning and Flattening and a Possible Inhibition of phot2 Signaling by phot1
Role of RPT2 in Leaf Positioning and Flattening and a Possible Inhibition of phot2 Signaling by phot1
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DOI：
10.1093/pcp/pcs094
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发表时间：
2013-01-01
影响因子：
4.9
通讯作者：
Shimazaki, Ken-ichiro
中科院分区：
文献类型：
--
作者：
Harada, Akiko;Takemiya, Atsushi;Shimazaki, Ken-ichiro
在弱、中、强白光(10、25和70亩MOLm(-2)S(-1))下，研究了蓝光受体趋光素(Pho1和Pho2)和根趋光性2(RPT2)在叶片定位和展平以及植物生长中的作用。RPT2介导叶片定位和扁平化，并以光依赖的方式促进植物生长。在弱光下，光1单独控制这些反应。在中光和强光下，光1和光2都会影响反应。这些结果表明，植物通过光1和光2利用大范围的光强度来优化植物的生长。Rpt2单一突变体的表型一般与Pho1-Pho2双突变体的表型相似。令我们惊讶的是，当PHOT1基因在rpt2突变体中被破坏时，得到的光1 rpt2双突变体显示了野生型植物在强光下的形态，而在双突变体中PHOT2的额外干扰取消了这种恢复。这表明，在缺少Phot1的情况下，Phot2可能发挥作用，并绕过RPT2将信号传递到下游元件。Rpt2突变体的表达和光诱导的自磷酸化不受影响。我们得出结论，RPT2以一种依赖于光1的方式调节叶片的扁平和定位，光1可能抑制光2信号通路。我们讨论了RPT2在促光体信号转导中的功能作用。
We investigated the roles of the blue light receptors phototropins (phot1 and phot2) and ROOT PHOTOTROPISM 2 (RPT2) in leaf positioning and flattening, and plant growth under weak, moderate and strong white light (10, 25 and 70 mu molm(-2) s(-1)). RPT2 mediated leaf positioning and flattening, and enhanced plant growth in a phot1-dependent manner. Under weak light, phot1 alone controls these responses. Under moderate and strong light, both phot1 and phot2 affect the responses. These results indicate that plants utilize a wide range of light intensities through phot1 and phot2 to optimize plant growth. The rpt2 single mutant generally exhibited phenotypes that resembled those of the phot1 phot2 double mutant. To our surprise, when the PHOT1 gene was disrupted in the rpt2 mutant, the resulting phot1 rpt2 double mutant showed the morphology of the wild-type plant under strong light, and additional disruption of PHOT2 in the double mutant abolished this recovery. This suggested that phot2 may function in the absence of phot1 and bypass RPT2 to transmit the signal to downstream elements. Expression and light-induced autophosphorylation of phot2 were not affected in the rpt2 mutant. We conclude that RPT2 mediates leaf flattening and positioning in a phot1-dependent manner, and that phot1 may inhibit the phot2 signaling pathways. We discuss the functional role of RPT2 in phototropin signaling.