Sahin F, Kotan R, Gergon E, Miller S A
Department of Plant Pathology, The Ohio State University, OARDC, Wooster 44691.
Philippines Rice Research Institute, Munoz, Luzon, Philippines.
Plant Dis. 1999 Jun;83(6):590. doi: 10.1094/PDIS.1999.83.6.590B.
Thirteen strains of Xanthomonas campestris pv. vesicatoria, causal agent of bacterial spot of pepper (Capsicum spp.) and tomato (Lycopersicum spp.), were isolated from six different pepper fields in the vicinity of Bongabon, Luzon, the Philippines. The strains were characterized based on sensitivity to copper and streptomycin, physiological tests, analysis of whole cell fatty acids (fatty acid methyl ester; FAME), serology, amplification of the 16S-23S rDNA spacer region, pathogenicity, and virulence on pepper and tomato differential genotypes as previously described (1,2). All of the Philippine strains were copper resistant (50 μg/ml), and streptomycin sensitive (20 μg /ml). None of the strains were pectolytic or amylolytic. FAME analysis showed that all strains had similar fatty acid profiles, and matched the strains to X. campestris (similarity indices [S.I.] = 0.186-0.455). With the universal primers 4F/7R, a DNA fragment (680 bp) was amplified from 16S-23S rDNA spacer regions of all Philippine strains. Serological fingerprints of the strains with a set of eight monoclonal antibodies (MAbs) in indirect enzyme-linked immunosorbent assay showed that all Philippine strains were serovar A1. Existence of the avrRxv gene in X. campestris pv. vesicatoria race T1 strains was also confirmed for all Philippine strains by amplifying a DNA fragment (approximately 0.7 kb) with the primer set RST 27/28. This is genetic evidence for race identity of the Philippine strains with T1. However, hypersensitive test results on pepper and tomato differential lines identified the Philippine strains as T2P7. These results showed that X. campestris pv. vesicatoria strains may contain the avrRxv gene, but it may not be functional. This is the first report of the observation of X. campestris pv. vesicatoria race T2P7 on pepper. References: (1) H. Bouzar et al. Phytopathology 84:664, 1994; (2) F. Sahin and S. A. Miller. Plant Dis. 82:794, 1998.
从菲律宾吕宋岛邦阿邦附近六个不同的辣椒田分离出了13株野油菜黄单胞菌辣椒斑点致病变种，该病菌可引发辣椒（辣椒属）和番茄（番茄属）的细菌性斑点病。按照之前描述的方法（1,2），基于对铜和链霉素的敏感性、生理测试、全细胞脂肪酸（脂肪酸甲酯；FAME）分析、血清学、16S - 23S rDNA间隔区扩增、致病性以及对辣椒和番茄鉴别基因型的毒力等对这些菌株进行了鉴定。所有菲律宾菌株都对铜具有抗性（50μg/ml），且对链霉素敏感（20μg/ml）。没有菌株具有果胶分解或淀粉分解能力。FAME分析表明，所有菌株具有相似的脂肪酸谱，与野油菜黄单胞菌的菌株相匹配（相似性指数[S.I.] = 0.186 - 0.455）。使用通用引物4F/7R，从所有菲律宾菌株的十六烷值 - 23S rDNA间隔区扩增出一个DNA片段（680bp）。在间接酶联免疫吸附测定中，用一组八种单克隆抗体（MAb）对菌株进行血清学指纹分析表明，所有菲律宾菌株均为血清型A1。通过用引物对RST 27/28扩增出一个DNA片段（约0.7kb），也证实了所有菲律宾菌株的野油菜黄单胞菌辣椒斑点致病变种T1小种中存在avrRxv基因。这是菲律宾菌株与T1小种具有相同小种的遗传证据。然而，在辣椒和番茄鉴别品系上的过敏反应测试结果将菲律宾菌株鉴定为T2P7。这些结果表明，野油菜黄单胞菌辣椒斑点致病变种菌株可能含有avrRxv基因，但它可能没有功能。这是关于在辣椒上观察到野油菜黄单胞菌辣椒斑点致病变种T2P7的首次报道。参考文献：（1）H. Bouzar等人，《植物病理学》84:664，1994年；（2）F. Sahin和S.A. Miller，《植物病害》82:794，1998年。
