Tang Dong-Jie, Li Xiang-Jiang, He Yong-Qiang, Feng Jia-Xun, Chen Baoshan, Tang Ji-Liang
The Key Laboratory of Ministry of Education for Microbial and Plant Genetic Engineering, Guangxi University, 100 Daxue Road, Nanning, Guangxi 530004, China.
Mol Plant Microbe Interact. 2005 Jul;18(7):652-8. doi: 10.1094/MPMI-18-0652.
Zur is a regulator of the high-affinity zinc uptake system in many bacteria. In Xanthomonas campestris pv. campestris 8004, a putative protein encoded by the open reading frame designated as XC1430 shows 42% amino acid similarity with the Zur of Escherichia coli. An XC1430-disrupted mutant 1430nk was constructed by homologous suicide plasmid integration. 1430nk failed to grow in rich medium supplemented with Zn2+ at a concentration of 400 microM and in nonrich medium supplemented with Zn2+ at a concentration of 110 microM, whereas the wild-type strain grew well in the same conditions. In rich medium with 400 microM Zn2+, 1430nk accumulated significantly more Zn2+ than the wild-type strain. 1430nk showed a reduction in virulence on the host plant Chinese radish (Raphanus sativus L. var. radiculus Pers.) and produced less extracellular polysaccharide (EPS) than did the wild-type strain in the absence of added zinc. These results revealed that XC1430 is a functional member of the Zur regulator family that controls zinc homeostasis, EPS production, and virulence in X. campestris pv. campestris.
Zur是许多细菌中高亲和力锌摄取系统的调节因子。在野油菜黄单胞菌野油菜致病变种8004中，由开放阅读框XC1430编码的一种假定蛋白与大肠杆菌的Zur具有42%的氨基酸相似性。通过同源自杀质粒整合构建了XC1430缺失突变体1430nk。1430nk在添加了浓度为400微摩尔的Zn2+的丰富培养基中以及添加了浓度为110微摩尔的Zn2+的非丰富培养基中无法生长，而野生型菌株在相同条件下生长良好。在含有400微摩尔Zn2+的丰富培养基中，1430nk积累的Zn2+比野生型菌株显著更多。在不添加锌的情况下，1430nk对寄主植物中国萝卜（Raphanus sativus L. var. radiculus Pers.）的毒力降低，并且产生的胞外多糖（EPS）比野生型菌株少。这些结果表明，XC1430是Zur调节因子家族的一个功能成员，它控制野油菜黄单胞菌野油菜致病变种中的锌稳态、EPS产生和毒力。
