Summary
Bacterial wilt caused by Ralstonia solanacearum is one of the most significant diseases of plantation Eucalyptus in southern China. In this study, 11 isolates were obtained from symptomatic individual trees from eucalypt plantations located in the key eucalypt-growing regions in China: Guangdong, Guangxi and Hainan. Cultures of these isolates were subject to morphological examination followed by DNA sequence comparisons to provide positive identification; all were confirmed to be R. solanacearum. Identification of the biovar types of all isolates obtained was then carried out using an improved biovar testing technique established in the course of this study. Ten of the isolates were shown to be biovar 3 of R. solanacearum, whilst the one other isolate appeared similar to one reported from a previous Chinese study on crop plants and designated as subtype 1 of biovar 4. This study represents the first detailed scientific investigation on the causal agent of Eucalyptus bacterial wilt in southern China.
Acknowledgements
We acknowledge financial support for this study through Chinese Ministry of Science and Technology project number 2012BAD19B08 and Forestry Bureau of Guangdong, China, project number 2010KJCX015-03. We thank Huizhou Nanyou Forestry Economic Development Co. Ltd, Jinhua Forestry Co. Ltd, and Guangxi Stora Enso Forestry Co. Ltd and colleagues of Longxian Ran, Mingling Yin, Shuaifei Chen, Runlei Chang and Shengkun Wang for their valuable assistance in both the field and the laboratory.