Suetsugu Noriyuki, Takemiya Atsushi, Kong Sam-Geun, Higa Takeshi, Komatsu Aino, Shimazaki Ken-Ichiro, Kohchi Takayuki, Wada Masamitsu
Department of Biology, Faculty of Sciences, Kyushu University, Fukuoka 819-0395, Japan; Graduate School of Biostudies, Kyoto University, Kyoto 606-8502, Japan
Department of Biology, Faculty of Sciences, Kyushu University, Fukuoka 819-0395, Japan;
Proc Natl Acad Sci U S A. 2016 Sep 13;113(37):10424-9. doi: 10.1073/pnas.1602151113. Epub 2016 Aug 30.
In green plants, the blue light receptor kinase phototropin mediates various photomovements and developmental responses, such as phototropism, chloroplast photorelocation movements (accumulation and avoidance), stomatal opening, and leaf flattening, which facilitate photosynthesis. In Arabidopsis, two phototropins (phot1 and phot2) redundantly mediate these responses. Two phototropin-interacting proteins, NONPHOTOTROPIC HYPOCOTYL 3 (NPH3) and ROOT PHOTOTROPISM 2 (RPT2), which belong to the NPH3/RPT2-like (NRL) family of BTB (broad complex, tramtrack, and bric à brac) domain proteins, mediate phototropism and leaf flattening. However, the roles of NRL proteins in chloroplast photorelocation movement remain to be determined. Here, we show that another phototropin-interacting NRL protein, NRL PROTEIN FOR CHLOROPLAST MOVEMENT 1 (NCH1), and RPT2 redundantly mediate the chloroplast accumulation response but not the avoidance response. NPH3, RPT2, and NCH1 are not involved in the chloroplast avoidance response or stomatal opening. In the liverwort Marchantia polymorpha, the NCH1 ortholog, MpNCH1, is essential for the chloroplast accumulation response but not the avoidance response, indicating that the regulation of the phototropin-mediated chloroplast accumulation response by RPT2/NCH1 is conserved in land plants. Thus, the NRL protein combination could determine the specificity of diverse phototropin-mediated responses.
在绿色植物中,蓝光受体激酶向光素介导各种光运动和发育反应,如向光性、叶绿体光定位运动(积累和回避)、气孔开放和叶片展平,这些都有助于光合作用。在拟南芥中,两种向光素(向光素1和向光素2)冗余介导这些反应。两种与向光素相互作用的蛋白,即非向光性下胚轴3(NPH3)和根向光性2(RPT2),属于BTB(广泛复合体、tramtrack和bric à brac)结构域蛋白的NPH3/RPT2样(NRL)家族,介导向光性和叶片展平。然而,NRL蛋白在叶绿体光定位运动中的作用仍有待确定。在这里,我们表明另一种与向光素相互作用的NRL蛋白,叶绿体运动的NRL蛋白1(NCH1),与RPT2冗余介导叶绿体积累反应,但不介导回避反应。NPH3、RPT2和NCH1不参与叶绿体回避反应或气孔开放。在地钱多歧藻中,NCH1的直系同源物MpNCH1对叶绿体积累反应至关重要,但对回避反应不重要,这表明RPT2/NCH1对向光素介导的叶绿体积累反应的调控在陆地植物中是保守的。因此,NRL蛋白组合可以决定多种向光素介导反应的特异性。