Bacterial Streak of Rye Caused by Xanthomonas campestris pv. cerealis (Hagborg 1942) Dye 1978

Abstract

In 1980, bacterial streak of rye caused by Xanthomonas campestris pv. cerealis (Hagborg 1942) Dye 1978 occurred in Hokkaido, Japan. The lesions on the leaves became at first water-soaked, dark-green spots and gradually elongate to form translucent brown streaks. The surface of the lesions was often covered with milky droplets of bacterial exudate under humid conditions and with thin, transparent films and/or yellow, resinous granules of excudates under dry conditions. Typical symptoms were produced on rye, barley, wheat and quack grass but not on smooth bromegrass, orchardgrass, timothy or rice by artificial inoculation. The bacteriological characteristics of the pathogen were determined: Cells were non-spore forming rods with a single flagellum, Gram-negative and aerobic. Yellow pigment and slime were produced on nutrient glucose agar. Glucose was oxidatively metabolized, but Kovacs' oxidase, urease and tyrosinase were negative. H₂S and ammonia were produced, but not 2-ketogluconate, indole or acetoin. Aesculin, Tween-80 and starch were hydrolysed, but not margarine or sodium hippurate. Gelatin was liquefied, and nitrate was not reduced. Growth on nutrient agar was inhibited by 0.02% TTC. Asparagine was inadequate as a sole source of carbon and nitrogen. Acid was produced from arabinose, xylose, glucose, fructose, galactose, mannose, sucrose, lactose, glycerol, cellobiose and trehalose, but not from rhamnose, maltose, raffinose, inulin, salicin, mannitol, sorbitol, adonitol, dulcitol or α-methyl-D-glycoside. Acetate, citrate, malate, succinate, propinate and lactate were utilized but not oxalate, gluconate or tartrate.