Abstract
Leaf spot similar to bacterial spot or bacterial shoot blight disease of tea were observed on tea leaves after a typhoon in Kagoshima Prefecture in 2007 and 2008; however, the causal agents of these bacterial diseases have not been isolated. Instead, four bacterial species that can induce a hypersensitive response (HR) symptom associated with the generation of hydrogen peroxide after infiltration of bacterial suspensions into tea leaf tissues were isolated from the leaf spot. Analyses of bacterial characteristics and the 16S rRNA gene sequences indicated that two dominant species among the four were most closely related to Herbaspirillum huttiense and Acidovorax avenae, respectively. These bacterial species did not cause lesions after needle-prick or spray inoculations under wet field conditions; however, spraying inoculum on a tea field under heavy storm conditions reproduced the same symptom within 1 to 2 d. Our data indicates that macroscopic HR symptoms can be caused by avirulent bacteria after heavy storms such as typhoons.
