Bacterial Blight of Sesame Caused by Xanthomonas campestris pv. sesami

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

Research in Plant Disease 2005;11(2):146-151.
Published online December 30, 2005.

Xanthomonas campestris pv. sesami에 의한 참깨의 세균성잎마름병

이승돈, 이정희, 김용기, 허성기, 나동수

Bacterial Blight of Sesame Caused by Xanthomonas campestris pv. sesami

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

Abstract

A new bacterial disease of sesam (Sesamum indicum) was observed on field-grown plants in Suwon, Hongchun and Yeonchun in 2000. Leaf symptoms initially appeared as water-soaked spots that gradually enlarged, became necrotic, and were often bordered by a small zone of lemon yellow tissue. In the case of severe infection, dead leaves were defoliated. 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 were purified and used for further tests. Pathogenicity of strains was confirmed on 3-week-old sesame plants sprayed with bacterial suspensions containing 10(8) cfu/ml of phosphate buffered saline. The Biolog and fatty acid analyses of the two strains(SL3451 and SL3476) from sesame leaf blight showed that they could be identified as X. campestris pv. sesami because of their high similarity to the tester strain(X. campestris pv. sesami LMG865) with a match probability of 100%. The bacterium grew well between 18 and 36℃, but optimum temperature was 27℃ on LB broth. This is the first report of bacterial blight of sesame in Korea. Symptoms of bacterial blight of sesame are difficult to differentiated with those of bacterial leaf spot caused by Pseudomonas syringae pv. sesami.

Key Words: Bacterial blight, Sesamum indicum, Xanthomonas campestris pv. sesami