Bathy Phytochromes in Rhizobial Soil Bacteria
Bathy Phytochromes in Rhizobial Soil Bacteria
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DOI：
10.1128/jb.00672-10
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发表时间：
2010-10-01
影响因子：
3.2
通讯作者：
Lamparter, Tilman
中科院分区：
文献类型：
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作者：
Rottwinkel, Gregor;Oberpichler, Inga;Lamparter, Tilman
光敏色素是在植物、细菌和真菌中发现的胆囊蛋白光感受器。光敏色素的原型具有Pr基态，它吸收红色光谱范围内的光，并被光转化为Pfr形式，它吸收波长较长的远红光。最近，一些细菌光敏色素经过Pr到Pfr的暗转化，因此具有Pfr基态。我们在这里表明，这种所谓的浴光敏色素广泛分布在细菌中，属于根瘤菌目。我们测量了具有一个或两个光敏色素基因的物种的体内光谱特性和暗转换方向。农杆菌C58含有一种光敏色素和另一种光敏色素，其在体内由Pfr暗转化为Pr。近缘种葡萄农杆菌S4也含有一种纯光敏色素和另一种具有新光谱特性的光敏色素。leguminosarum 3841、Rhizobium etli CIAT652和Azorhizobium caulinodans ORS571含有一种裸色型光敏色素，而自养黄杆菌Py2含有一种光敏色素，可以将Pfr转化为Pr。我们认为裸色色素是对土壤光环境的适应。大多数细菌光敏色素是光调节组氨酸激酶，其中一些在同一蛋白上具有c端反应调节亚基。根据我们的系统发育研究，具有这种结构域排列的光敏色素群是从一个健康的光敏色素祖先进化而来的。
Phytochromes are biliprotein photoreceptors that are found in plants, bacteria, and fungi. Prototypical phytochromes have a Pr ground state that absorbs in the red spectral range and is converted by light into the Pfr form, which absorbs longer-wavelength, far-red light. Recently, some bacterial phytochromes have been described that undergo dark conversion of Pr to Pfr and thus have a Pfr ground state. We show here that such so-called bathy phytochromes are widely distributed among bacteria that belong to the order Rhizobiales. We measured in vivo spectral properties and the direction of dark conversion for species which have either one or two phytochrome genes. Agrobacterium tumefaciens C58 contains one bathy phytochrome and a second phytochrome which undergoes dark conversion of Pfr to Pr in vivo. The related species Agrobacterium vitis S4 contains also one bathy phytochrome and another phytochrome with novel spectral properties. Rhizobium leguminosarum 3841, Rhizobium etli CIAT652, and Azorhizobium caulinodans ORS571 contain a single phytochrome of the bathy type, whereas Xanthobacter autotrophicus Py2 contains a single phytochrome with dark conversion of Pfr to Pr. We propose that bathy phytochromes are adaptations to the light regime in the soil. Most bacterial phytochromes are light-regulated histidine kinases, some of which have a C-terminal response regulator subunit on the same protein. According to our phylogenetic studies, the group of phytochromes with this domain arrangement has evolved from a bathy phytochrome progenitor.