First Report of Pear Blossom Blast Caused by Pseudomonas syringae pv. syringae in China.
First Report of Pear Blossom Blast Caused by Pseudomonas syringae pv. syringae in China.
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DOI：
10.1094/pdis-92-5-0832c
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发表时间：
2008-04
期刊：
影响因子：
4.5
通讯作者：
L. Xu;G. Xie;B. Li;B. Zhu;F. S. Xu;J. Qian
中科院分区：
文献类型：
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作者：
L. Xu;G. Xie;B. Li;B. Zhu;F. S. Xu;J. Qian
2006年春天，在中国浙江省杭州市附近的梨园中发现了一种新的细菌性病害。该病在梨（Pyrus pyrifolia; cv.崔官）。该病的早期症状包括正在发育的果实的萼端变黑，开花簇变黑而受影响的开花簇的叶子看起来正常，或由花和叶组成的簇死亡。后来，树枝的尖端变成了深褐色，死了。未观察到细菌渗出。从10个花蕾和花朵样品中回收了12个细菌分离物。选择6个分离株进行鉴定。它们与假单胞菌pv.在基于Biolog微生物鉴定系统（4.2版; Biolog Inc.，海沃德，CA），致病性试验，使用微生物鉴定系统（Microbial Identification System，纽瓦克，DE），用需氧细菌文库（TABA 50）和电子显微镜（TEM，KYKY-1000 B，日本）。所有供试分离株均为革兰氏阴性需氧杆菌，大小为1.5至2.4 × 0.5至0.6 μm，具有2至4个极鞭毛。在King's培养基B上产生荧光绿色扩散颜料。菌落呈灰白色，在营养琼脂上略微凸起，边缘光滑。它们在蔗糖营养琼脂上产生莱万。在烟草品种‘cv.接种后24 h本氏。所有分离株均鉴定为P. Biolog相似性指数为0.57 - 0.86，FAME相似性指数为0.58 - 0.81。鉴定为P. p.用16 S rDNA通用引物（2，3）：5 '-阿加GTT TGA TCA TGG CTC AG-3'正向引物，5 '-ACG GTT ACC TTG TTA CGA CTT-3'反向引物对烟草赤星病菌进行鉴定。对3个分离株的PCR片段进行测序，并与GenBank中的序列进行比较。它们与P.甜菜碱16 S rRNA基因菌株NCPPB 3869。在盆中生长的原始梨栽培品种的芽和烧瓶中的分离的梨花上通过在18至22°C下用含有108 CFU/ml的六个分离物的细胞悬浮液喷雾接种进行Koch的假设，重复两次。该细菌在芽和花上诱导的症状与田间观察到的症状相似。从有症状的梨芽和内部卵巢组织中重新分离出细菌。黑腐病菌1914年，在英国首次报道了梨开花瘟的原因（1）。经检索中国农业数据库和主要期刊（国家知识基础数据库、维普中文期刊数据库、万方数据库、中国信息银行、中国科学院、植物病理学报、植叶学报、果树学报），发现这是国内首次报道开花霉P. erichingae pv.在中国，梨树病害循环规律及防治对策正在进一步研究中。参考文献：（1）B。P. Barker等人，Ann.Appl.Biol.1：85，1914。(2)联合Edward等，Nucleic Acids Res.17：7843，1989。(3)B。Li等人，J. Phytopathol. 34：141，2006.
In the spring of 2006, a new bacterial disease was noted in pear orchards near Hangzhou, Zhejiang Province, China. The disease caused severe blossom blast on pears (Pyrus pyrifolia; cv. Cuiguan). Early symptoms of the disease included blackening of the calyx end of developing fruit, blackening of blossom clusters while leaves of affected blossom clusters appeared normal, or death of clusters consisting of both blossoms and leaves. Later, tips of twigs turned dark brown and died. No bacterial ooze was observed. Twelve bacterial isolates were recovered from ten samples of buds and blossoms. Six isolates were selected for identification. They were similar to those of the reference strains of Pseudomonas syringae pv. syringae LMG5570 and LMG 2230 from Belgium in phenotypic tests on the basis of the Biolog Microbial Identification System (version 4.2; Biolog Inc., Hayward, CA), pathogenicity tests, gas chromatographic analysis of fatty acid methyl esters (FAMEs) using the Microbial Identification System (MIDI Inc., Newark, DE) with aerobic bacterial library (TABA50), and electron microscopy (TEM, KYKY-1000B, Japan). All isolates tested were gram-negative, aerobic rods measuring 1.5 to 2.4 × 0.5 to 0.6 μm with 2 to 4 polar flagella. Fluorescent green diffusible pigment was produced on King's Medium B. Colonies were gray-white and slightly raised with smooth margins on nutrient agar. They produced levan on sucrose nutrient agar. A hypersensitive reaction was observed on tobacco cv. Benshi 24 h after inoculation. All isolates were identified as P. syringae pv. syringae with Biolog similarity index of 0.57 to 0.86 and FAME similarity index of 0.58 to 0.81. Identification as P. syringae pv. syringae was confirmed using 16S rDNA universal primers (2,3): 5'-AGA GTT TGA TCA TGG CTC AG-3' forward primer, 5'-ACG GTT ACC TTG TTA CGA CTT-3' reverse primer. The PCR fragments of the three isolates were sequenced and compared with sequences in GenBank. They had 99% similiarity with P. syringae pv. syringae 16S rRNA gene strain NCPPB 3869. Koch's postulates were conducted on buds of the original pear cultivar growing in pots and detached pear blossoms in flasks by spray inoculation with cell suspensions containing 108 CFU/ml of the six isolates at 18 to 22°C with two replications. The bacteria induced symptoms on buds and blossoms similar to those observed in the field. The bacterium was reisolated from symptomatic pear buds and internal ovary tissues. P. syringae pv. syringae was first reported in England as the cause of pear blossom blast in 1914 (1). After searching all the Chinese agricultural databases and major journals (National Knowledge Infrastructure database, Vip Chinese periodical database, Chinese wanfang database, China InfoBank, Scientia Agricultura Sinica, Acta Phytopathologica Sinica, Acta Phytophylacica Sinica, and Journal of Fruit Science), to our knowledge, this is the first report of pear blossom blast caused by P. syringae pv. syringae in China. The disease cycle on pear trees and the control strategies in the regions are being further studied. References: (1) B. P. Barker et al. Ann. Appl. Biol. 1:85, 1914. (2) U. Edward et al. Nucleic Acids Res. 17:7843,1989. (3) B. Li et al. J. Phytopathol. 34:141, 2006.