Light regulates attachment, exopolysaccharide production, and nodulation in Rhizobium leguminosarum through a LOV-histidine kinase photoreceptor
Light regulates attachment, exopolysaccharide production, and nodulation in Rhizobium leguminosarum through a LOV-histidine kinase photoreceptor
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DOI：
10.1073/pnas.1121292109
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发表时间：
2012-07-24
影响因子：
11.1
通讯作者：
Goldbaum, Fernando A.
中科院分区：
文献类型：
--
作者：
Bonomi, Hernan R.;Posadas, Diana M.;Goldbaum, Fernando A.
豆科根瘤菌是一种侵染根毛并诱导豆科植物形成固氮根瘤的土壤细菌。光、氧和电压(LOV)结构域蛋白是在高等植物和许多藻类、真菌和细菌中发现的蓝光受体。豆类根结线虫的基因组。Viciae 3841是一个花生调节内共生菌，它编码一个N-末端含有LOV结构域的传感器组氨酸激酶(R-LOV-HK)。R-LOV-HK具有典型的LOV结构域吸收光谱，在蓝色和UV-A区域有较宽的吸收带，并显示出截断的光循环。在这里，我们表明，R-LOV-HK蛋白调节附着在非生物表面上，以及鞭毛蛋白和胞外多糖的产生对光的响应。此外，在接种豌豆根之前对细菌培养物进行光照，可以增加每株的根瘤数量和根瘤内类杆菌的数量。光对结瘤的影响依赖于一个起作用的LOV基因。这项工作的结果表明，R-LOV-HK感受到的光是控制豆腐病菌适应反应和共生效率的一个重要环境因素。
Rhizobium leguminosarum is a soil bacterium that infects root hairs and induces the formation of nitrogen-fixing nodules on leguminous plants. Light, oxygen, and voltage (LOV)-domain proteins are blue-light receptors found in higher plants and many algae, fungi, and bacteria. The genome of R. leguminosarum bv. viciae 3841, a peanodulating endosymbiont, encodes a sensor histidine kinase containing a LOV domain at the N-terminal end (R-LOV-HK). R-LOV-HK has a typical LOV domain absorption spectrum with broad bands in the blue and UV-A regions and shows a truncated photocycle. Here we show that the R-LOV-HK protein regulates attachment to an abiotic surface and production of flagellar proteins and exopolysaccharide in response to light. Also, illumination of bacterial cultures before inoculation of pea roots increases the number of nodules per plant and the number of intranodular bacteroids. The effects of light on nodulation are dependent on a functional lov gene. The results presented in this work suggest that light, sensed by R-LOV-HK, is an important environmental factor that controls adaptive responses and the symbiotic efficiency of R. leguminosarum.