Mirik M, Selcuk F, Aysan Y, Sahin F
Department of Plant Protection, Faculty of Agriculture, Namik Kemal University, TR-59030 Tekirdag, Turkey.
Department of Plant Protection, Faculty of Agriculture, Cukurova University, TR-01330 Adana, Turkey.
Plant Dis. 2008 Jan;92(1):176. doi: 10.1094/PDIS-92-1-0176C.
During warm and humid periods in the winters of 2004 to 2006, severe leaf necrosis and vein rot symptoms were observed on cabbage (Brassica oleracea var. capitata L.), broccoli (Brassica oleracea var. italica Plenck.), and Brussels sprouts (Brassica oleracea var. gemmifera D.C.) in the Mediterranean Region of Turkey. Symptoms were characterized by yellow, V-shaped areas of the leaf margin, with the internal tissue turning from brown to black. Infected seedlings were also observed in commercial nurseries in Adana with a disease incidence of nearly 10 to 25%. Isolations made from leaves and veins of the affected plants on yeast dextrose calcium carbonate agar yielded yellow, mucoid, and convex colonies. Twenty isolates recovered from diseased leaf samples were selected at random to identify the causal organism. All isolates were nonspore forming, gram negative, rod shaped, motile, aerobic, oxidase-negative, catalase-positive, and amylolytic-positive (3). All isolates induced hypersensitive responses on tobacco (Nicotiana tabacum cv. Samsun). The isolates were identified as Xanthomonas campestris pv. campestris on the basis of fatty acid methyl ester (FAME) profiles determined by Sherlock Microbial Identification System software (Microbial ID, Newark, DE) and indirect ELISA. The similarity indices for the FAME analysis ranged from 80 to 94% (2). Indirect ELISA with a polyclonal antibody (Agdia, Elkhart IN; BRA 97000/0500) further confirmed the identity of the pathogen in both pure culture and infected plant. The mean absorbance values for three replications of indirect ELISA tests ranged from 1.411 to 3.508 at a wavelength of A (1). Pathogenicity of the isolates was tested on 5-week-old cabbage plants by spray inoculation using bacterial suspensions (10 CFU/ml) prepared in saline buffer (0.85% NaCl). Sterile saline buffer was sprayed on negative control plants. Inoculated and control plants were maintained for 5 days at 25°C and 70% relative humidity to observe symptom development. No symptoms developed on negative control plants. The bacterium was reisolated from inoculated cabbage plants and identified as X. campestris pv. campestris by FAME and an ELISA test. To our knowledge, this is the first report of the occurrence and outbreak of X. campestris pv. campestris in the Mediterranean Region of Turkey. References: (1) A. M. Alvarez et al. Phytopathology 84:1449, 1994. (2) A. R. Chase et al. Phytopathology 82:754, 1992. (3) N. W Schaad et al. Xanthomonas. Page 175 in: Laboratory Guide for Identification of Plant Pathogenic Bacteria. 3rd ed. N. W. Schaad et al., eds. American Phytopathological Society. St. Paul, MN, 2001.
在2004年至2006年冬季温暖潮湿的时期，土耳其地中海地区的卷心菜（甘蓝变种甘蓝）、西兰花（甘蓝变种意大利芥蓝）和抱子甘蓝（甘蓝变种芽甘蓝）上观察到严重的叶片坏死和叶脉腐烂症状。症状表现为叶片边缘呈黄色的V形区域，内部组织从褐色变为黑色。在阿达纳的商业苗圃中也观察到受感染的幼苗，发病率接近10%至25%。从患病植物的叶片和叶脉在酵母葡萄糖碳酸钙琼脂上进行分离，得到黄色、黏液状和凸起的菌落。从患病叶片样本中随机挑选出20个分离株以鉴定致病生物。所有分离株均无芽孢形成，革兰氏阴性，杆状，具运动性，需氧，氧化酶阴性，过氧化氢酶阳性，且淀粉分解阳性（3）。所有分离株在烟草（烟草品种萨姆松）上引发过敏反应。根据由Sherlock微生物鉴定系统软件（微生物ID，纽瓦克，特拉华州）测定的脂肪酸甲酯（FAME）谱和间接ELISA，这些分离株被鉴定为野油菜黄单胞菌野油菜致病变种。FAME分析的相似性指数范围为80%至94%（2）。使用多克隆抗体（Agdia，埃尔克哈特，印第安纳州；BRA 97000/0500）进行的间接ELISA进一步证实了纯培养物和受感染植物中病原体的身份。间接ELISA测试三次重复的平均吸光度值在波长A处范围为1.411至3.508（1）。通过使用在生理盐水缓冲液（0.85% NaCl）中制备的细菌悬液（10 CFU/ml）进行喷雾接种，在5周龄的卷心菜植株上测试分离株的致病性。将无菌生理盐水缓冲液喷洒在阴性对照植株上。接种和对照植株在25°C和70%相对湿度下保持5天以观察症状发展。阴性对照植株未出现症状。从接种的卷心菜植株中重新分离出该细菌，并通过FAME和ELISA测试鉴定为野油菜黄单胞菌野油菜致病变种。据我们所知，这是野油菜黄单胞菌野油菜致病变种在土耳其地中海地区发生和爆发的首次报道。参考文献：（1）A. M. 阿尔瓦雷斯等人。植物病理学84:1449，1994。（2）A. R. 蔡斯等人。植物病理学82:754，1992。（3）N. W. 沙德等人。黄单胞菌属。载于：植物病原细菌鉴定实验室指南。第3版。N. W. 沙德等人编。美国植物病理学会。圣保罗，明尼苏达州，2001。
