A LuxR homologue of Xanthomonas oryzae pv. oryzae is required for optimal rice virulence
A LuxR homologue of Xanthomonas oryzae pv. oryzae is required for optimal rice virulence
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DOI：
10.1111/j.1364-3703.2007.00415.x
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发表时间：
2007-07-01
影响因子：
4.9
通讯作者：
Venturi, Vittorio
中科院分区：
文献类型：
--
作者：
Ferluga, Sara;Bigirimana, Joseph;Venturi, Vittorio
在革兰氏阴性菌中，典型的群体感应（QS）系统通常涉及酰化高丝氨酸内酯（AHL）的产生和应答。阿勒QS系统最常由LuxI家族阿勒合酶和LuxR家族阿勒反应调节剂介导。本研究首次报道了一个LuxR家族型调节器的存在下，黄单胞菌pv。（Xoo），已被指定为OryR。OryR的一级结构包含阿勒QS LuxR家族反应调节因子的典型特征结构域：AHL结合和HTH DNA结合基序。oryR基因在26个Xoo菌株中是保守的，并且也存在于近亲X的基因组中。野油菜致病变种campestris和X.轴足虫变种柑橘。在三个Xoo菌株中破坏oryR导致水稻毒性的显着降低。野生型Xoo菌株似乎不产生AHL，并且Xoo测序基因组的分析没有揭示LuxI家族阿勒合酶的存在。OryR蛋白被证明是由浸渍大米诱导的，并影响两种分泌蛋白的产生：一种细胞壁降解纤维二糖苷酶和一种功能未知的20 kDa蛋白。通过表达和纯化OryR，然后观察到当在稻提取物存在下生长时其被溶解，表明稻中可能存在结合OryR的分子。OryR作为一种可能的植物诱导的LuxR家族调节剂的作用进行了讨论。
In Gram-negative bacteria a typical quorum sensing (QS) system usually involves the production and response to acylated homoserine lactones (AHLs). An AHL QS system is most commonly mediated by a LuxI family AHL synthase and a LuxR family AHL response regulator. This study reports for the first time the presence of a LuxR family-type regulator in Xanthomonas oryzae pv. oryzae (Xoo), which has been designated as OryR. The primary structure of OryR contains the typical signature domains of AHL QS LuxR family response regulators: an AHL-binding and a HTH DNA binding motif. The oryR gene is conserved among 26 Xoo strains and is also present in the genomes of close relatives X. campestris pv. campestris and X. axonopodis pv. citri. Disrupting oryR in three Xoo strains resulted in a significant reduction of rice virulence. The wild-type Xoo strains do not seem to produce AHLs and analysis of the Xoo sequenced genomes did not reveal the presence of a LuxI-family AHL synthase. The OryR protein was shown to be induced by macerated rice and affected the production of two secreted proteins: a cell-wall-degrading cellobiosidase and a 20-kDa protein of unknown function. By expressing and purifying OryR it was then observed that it was solubilized when grown in the presence of rice extract indicating that there could be a molecule(s) in rice which binds OryR. The role of OryR as a possible in planta induced LuxR family regulator is discussed.