Bacterial Leaf Spot and Dry Rot of Lettuce Caused by Xanthomonas campestris pv. vitians

Lee, Seung Don; Lee, Jung Hee; Kim, Yong Ki; Heu, Sung Gi; Ra, Dong Soo

Research in Plant Disease 2007;13(1):66-70.
Published online April 30, 2007.

Xanthomonas campestris pv. vitians에 의한 상추 세균성점무늬병

이승돈, 이정희, 김용기, 허성기, 나동수

Bacterial Leaf Spot and Dry Rot of Lettuce Caused by Xanthomonas campestris pv. vitians

Seung Don Lee, Jung Hee Lee, Yong Ki Kim, Sung Gi Heu, Dong Soo Ra

Abstract

During 1997 and 1998, a new disease of lettuce (Lactuca sativa) was observed on greenhouse-grown plants in Kwangju and Kwangmyung. Lesions on leaves were irregular, small, pale green to black, water-soaked, and 2 to 5 mm in diameter. Coalescing lesions sometimes caused defoliation of older leaves. Isolations made from diseased leaves on yeast extract dextrose calcium carbonate agar yielded nearly pure cultures of a yellow pigmented bacterium typical of a xanthomonad. Two bacterial strains (SL0246 and SL1352) were purified and used for further tests. Pathogenicity of strains was confirmed on 5-week-old lettuce plants injected with bacterial suspensions containing 108 cfu/ml of phosphate buffered saline. The representative Xanthomonas strains isolated from lettuce were compared with a reference strain X. campestris pv. vitians for fatty acid profiles and metabolic fingerprints using GN2 microplate, showing that all outcomes were indistinguishable between the representative and reference strains. This is the first report of bacterial leaf spot and dry rot of lettuce in Korea.

Key Words: Bacterial leaf spot, Lactuca sativa, Xanthomonas campestris pv. vitians