Link to home

The Zinc Uptake Regulator Zur Is Essential for the Full Virulence of Xanthomonas campestris pv. campestris

July 2005 , Volume 18 , Number  7
Pages  652 - 658

Dong-Jie Tang , 1 , 2 Xiang-Jiang Li , 2 Yong-Qiang He , 1 , 2 Jia-Xun Feng , 1 , 2 Baoshan Chen , 1 , 2 and Ji-Liang Tang 1 , 2

1The Key Laboratory of Ministry of Education for Microbial and Plant Genetic Engineering, 2Guangxi Key Laboratory of Subtropical Bioresources Conservation and Utilization, Guangxi University, 100 Daxue Road, Nanning, Guangxi 530004, China

Go to article:
Accepted 14 February 2005.

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 μM and in nonrich medium supplemented with Zn2+ at a concentration of 110 μM, whereas the wild-type strain grew well in the same conditions. In rich medium with 400 μM 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.

© 2005 The American Phytopathological Society