A Single Mutation in the oprF mRNA Leader Confers Strict Translational Control by the Gac/Rsm System in Pseudomonas fluorescens CHA0
A Single Mutation in the oprF mRNA Leader Confers Strict Translational Control by the Gac/Rsm System in Pseudomonas fluorescens CHA0
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DOI：
10.1007/s00284-008-9306-6
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发表时间：
2009-02-01
影响因子：
2.6
通讯作者：
Valverde, Claudio
中科院分区：
文献类型：
--
作者：
Alvarez Crespo, Maria Cecilia;Valverde, Claudio
荧光假单胞菌CHA 0能够拮抗多种作物植物上的真菌植物病原体，这主要是由于次级代谢产物的产生，所述次级代谢产物由全局调节Gac/Rsm级联协同上调。双组分系统GacS/GacA激活三种小调节RNA RsmX、RsmY和RsmZ的转录，其抵消RsmA和RsmE蛋白对靶mRNA的翻译抑制。在基于RsmA/RsmE控制所需的mRNA前导序列上的最小序列寻找新的Gac/Rsm靶标时，主要孔蛋白OprF的前导区成为候选者。虽然一个同基因的CHA 0 oprF突变体表现出降低的能力，附着到黄瓜和番茄的根，这表明OprF在根定殖的病原体拮抗作用的一个必要条件，翻译oprF“-”lacZ融合弱调控的Gac/Rsm，尽管它的高序列相似性的hcnA的领导人。单个碱基取代使修饰的oprF 5 '-UTR处于Gac/Rsm的严格控制下。结果突出了Gac/RSM靶的细微序列要求。
The rhizobacterium Pseudomonas fluorescens CHA0 is able to antagonize fungal phytopathogens on a variety of crop plants, mainly due to the production of secondary metabolites that are coordinately upregulated by the global regulatory Gac/Rsm cascade. The two-component system GacS/GacA activates transcription of the three small regulatory RNAs RsmX, RsmY, and RsmZ, which counteract translational repression of target mRNAs by RsmA and RsmE proteins. In a search for novel Gac/Rsm targets based on the minimal sequence on mRNA leaders required for RsmA/RsmE control, the leader region of the major porin OprF emerged as a candidate. Although an isogenic CHA0 oprF mutant showed a reduced ability to attach to cucumber and tomato roots, suggesting a role for OprF in root colonization as a requisite for pathogen antagonism, a translational oprF'-'lacZ fusion was weakly regulated by Gac/Rsm despite its high sequence similarity to the hcnA leader. A single base substitution put the modified oprF 5'-UTR under strict control by Gac/Rsm. The results highlight the subtle sequence requirements of Gac/Rsm targets.