The Erwinia chrysanthem phoP-phoQ operon plays an important role in growth at low pH, virulence and bacterial survival in plant tissue
The Erwinia chrysanthem phoP-phoQ operon plays an important role in growth at low pH, virulence and bacterial survival in plant tissue
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DOI：
10.1046/j.1365-2958.2003.03583.x
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发表时间：
2003-07-01
影响因子：
3.6
通讯作者：
Rodríguez-Palenzuela, P
中科院分区：
文献类型：
--
作者：
Llama-Palacios, A;López-Solanilla, E;Rodríguez-Palenzuela, P
我们研究了酸性pH对菊花欧文氏菌植物质外体定植的屏障作用。使用一个含有无启动子报告基因gus的微型转座子对细菌基因组进行随机突变。分离到一个名为BT1119的酸敏感突变体，它与野生型菌株相比具有以下不同特征：(I)在pH小于或等于5.5时不能生长；(Ii)在酸性pH和植物组织中的存活率降低；(Iii)对抗菌肽的敏感性增加；(Iv)菊苣叶片和梨果实的毒性降低；(V)多聚半乳糖醛酸酶的产生减少；以及(Vi)侵染后菊苣组织的碱化能力降低。中断基因的序列与PhoQ基因高度相似，PhoQ基因参与了几种细菌的环境感知，如假结核耶尔森菌、胡萝卜欧文氏菌、鼠伤寒沙门氏菌和大肠杆菌，因此，这个名称被用于E.chrysenhemi系统。该基因在低浓度的镁离子和植物中被诱导。这些结果表明，菊花E.php-PhoQ系统在细菌侵染初期对植物组织中的细菌存活起着重要的作用。
We have studied the role of acidic pH as a barrier for the colonization of the plant apoplast by Erwinia chrymsanthemi. A minitransposon containing a promoterless reporter gene, gus, was used for random mutagenesis of the bacterial genome. An acid-sensitive mutant, named BT1119, was isolated and had the following differential features with respect to the wildtype strain: (i) inability to grow at pH less than or equal to 5.5; (ii) decreased survival at acid pH and in plant tissues; (iii) increased susceptibility to antimicrobial peptides; (iv) decreased virulence in chicory leaves and pear fruits; (v) reduced polygalacturonase production; and (vi) reduced ability to alkalinize chicory tissues after infection. The sequence of the interrupted gene was highly similar to the phoQ gene, which is involved in environmental sensing in several bacteria, such as Yersinia pseudotuberculosis, Erwinia carotovora, Salmonella typhimurium and Escherichia coli and thus, this designation was used for the E. chrysenthemi system. This gene was induced at low Mg2+ concentrations and in planta. These results suggest that E. chrysanthemi PhoP-PhoQ system plays an important role in bacterial survival in plant tissues during the initial infection stages.