In summer of 2016, cankers were observed on 8-year-old pear trees (Pyrus communis L.) cv. Yali grafted on the Caleriana rootstock, in a commercial orchard in Monte Castelo, SC. Eight hundred out of 1200 trees died and the rest of the orchard was eradicated. Affected plants showed cankers on trunks and twigs with exudation; the branches turned brown and slowly died. Bacterial colonies were isolated on King’s B medium from infected tissues. Pathogenicity, biochemical tests were conducted and some isolates selected for whole genome sequencing using Ion Personal Genome Machine™ (PGM™) System (ThermoFisher Scientific). PCR with Y1/Y2 and PcaF/PcaR primers, specific for Pectobacterium carotovorum and Pectobacterium carotovorum subsp. actinidiae, respectively, were also carried out. The section of inoculated apple and pear branches showed longitudinal darkening, with wilt and leaf blight. Shoots of kiwifruit Actinidia deliciosa cv. Hayward inoculated with the bacterium showed no symptoms. The bacterium was re-isolated from all symptomatic tissues, satisfying Koch’s postulates. Selected isolates were gram-negative, facultative anaerobic, rod-shaped and exhibited a strong pectolytic activity in potato and carrot disks, and showed similar biochemical profile using a BIOLOG GEN III MicroPlate. The pathogen of the symptoms observed on pear trees in Brazil show highest genome (87.1%; DDH analysis) and proteome identity (99.8%; Patric analysis) with P. carotovorum subsp. actinidiae. A product of the expected size was obtained in both specific PCR (Y1/Y2 (434 bp) and PcaF/PcaR (343 bp) primer pairs). Results from the present study clearly show that P. carotovorum subsp. actinidiae was associated with canker on pear trees in Santa Catarina, Brazil.

在2016年夏季，在8岁的梨树（Pyrus communis L.）简历上发现了溃疡病。Yali在南卡罗来纳州蒙特卡斯特洛的一家商业果园中嫁接了Caleriana砧木。1200棵树中有800棵死了，其余的果园也被消灭了。受影响的植物在树干和嫩枝上出现溃疡，并有渗出。树枝变成褐色，慢慢死去。在King's B培养基上从感染组织中分离出细菌菌落。使用Ion Personal Genome Machine™（PGM™）系统（ThermoFisher Scientific）进行了致病性，生化测试，并选择了一些分离物用于全基因组测序。使用Y1 / Y2和PcaF / PcaR引物进行PCR，这些引物对胡萝卜杆菌和胡萝卜杆菌亚种具有特异性。猕猴桃分别也进行了。接种的苹果和梨的分支部分显示出纵向变暗，枯萎和叶片枯萎。猕猴桃猕猴桃猕猴桃的芽。用该细菌接种的海沃德未显示任何症状。从所有有症状的组织中重新分离出细菌，满足了科赫的假设。选定的分离物为革兰氏阴性，兼性厌氧，杆状，并在马铃薯和胡萝卜盘中表现出很强的果胶分解活性，并使用BIOLOG GEN III MicroPlate表现出相似的生化特征。在巴西梨树上观察到的症状病原体与胡萝卜假单胞菌亚种显示出最高的基因组（87.1％； DDH分析）和蛋白质组同一性（99.8％； Patric分析）。猕猴桃。在特异性PCR（Y1 / Y2（434 bp）和PcaF / PcaR（343 bp）引物对）中均获得了预期大小的产物。从本研究的结果清楚地表明，胡萝卜假单胞菌亚种。猕猴桃与巴西圣卡塔琳娜州梨树上的溃疡病有关。