A Novel RAYM_RS09735/RAYM_RS09740 Two-Component Signaling System Regulates Gene Expression and Virulence in Riemerella anatipestifer.
A Novel RAYM_RS09735/RAYM_RS09740 Two-Component Signaling System Regulates Gene Expression and Virulence in Riemerella anatipestifer.
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DOI：
10.3389/fmicb.2017.00688
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发表时间：
2017
影响因子：
5.2
通讯作者：
Li Z
中科院分区：
文献类型：
--
作者：
Wang Y;Lu T;Yin X;Zhou Z;Li S;Liu M;Hu S;Bi D;Li Z
鸭疫里默氏阴性杆菌是一种重要的水禽病原菌，给养鸭业造成了重大的经济损失。然而，在鸭疫杆菌感染过程中，介导致病的毒力因子知之甚少。在本研究中，通过生物信息学分析预测了Raym_RS09735和Raym_RS09740将形成一个双组分信号系统。该TCS在黄杆菌科植物中高度保守。构建了突变株YmΔRS09735/RS09740，研究其在鸭疫杆菌毒力和基因调控中的作用。YmΔRS09735/RS09740的半数致死量(LD50)为1011cfu，与无毒菌株相当。YmΔRS09735/RS09740株在心、脑、肝、血和脾中的细菌丰度显著低于野生型鸭疫杆菌Ym株。苏木精伊红染色病理分析表明，与野生型相比，突变株YmΔRS09735/RS09740对感染雏鸭的致病力显著降低。RYM_RS09735/RYM_RS09740 TCS的RNAseq和Real-Time-PCR分析表明，该TCS是PhP/Phor系统。这是一种针对革兰氏阴性菌的新型TCS。在YMΔRS09735/RS09740株中，Tcs基因表达上调的基因有112个，下调的基因有693个(约33%的基因存在差异表达)。综上所述，我们首次报道了在革兰氏阴性菌中发现的Phop/Phor TCS，并证明它参与了鸭疫杆菌的毒力和基因调控。
The Gram-negative bacterium Riemerella anatipestifer is an important waterfowl pathogen, causing major economic losses to the duck-producing industry. However, little is known of the virulence factors that mediate pathogenesis during R. anatipestifer infection. In this study, RAYM_RS09735 and RAYM_RS09740 were predicted to form a two-component signaling system (TCS) through bioinformatics analysis. This TCS was highly conserved across the Flavobacteriaceae. A mutant YMΔRS09735/RS09740 strain was constructed to investigate the role of the RAYM_RS09735/RAYM_RS09740 TCS in R. anatipestifer virulence and gene regulation. The median lethal dose (LD50) of YMΔRS09735/RS09740 was found to be >1011 CFU, equivalent to that of avirulent bacterial strains. The bacterial abundances of the YMΔRS09735/RS09740 strain in the heart, brain, liver, blood, and spleen were significantly lower than that of the wild-type R. anatipestifer YM strain. Pathological analysis using hematoxylin and eosin staining showed that, compared to the wild-type, the mutant YMΔRS09735/RS09740 strain caused significantly less virulence in infected ducklings. RNAseq and real-time PCR analysis indicated that the RAYM_RS09735/RAYM_RS09740 TCS is a PhoP/PhoR system. This is a novel type of TCS for Gram-negative bacteria. The TCS was also found to be a global regulator of expression in R. anatipestifer, with 112 genes up-regulated and 693 genes down-regulated in the YMΔRS09735/RS09740 strain (~33% genes demonstrated differential expression). In summary, we have reported the first PhoP/PhoR TCS identified in a Gram-negative bacterium and demonstrated that it is involved in virulence and gene regulation in R. anatipestifer.