Ivanović Milan, Prokić Anđelka, Gašić Katarina, Menković Jelena, Kuzmanović Nemanja, Zlatković Nevena, Obradović Aleksa
University of Belgrade-Faculty of Agriculture, 11080 Belgrade-Zemun, Serbia.
Institute for Plant Protection and Environment, 11040 Belgrade, Serbia.
Plant Dis. 2023 Mar;107(3):826-833. doi: 10.1094/PDIS-06-22-1425-RE. Epub 2023 Mar 7.
During May 2016, severe blight symptoms were observed in several raspberry and blackberry fields in Serbia. In total, 22 strains were isolated: 16 from symptomatic raspberry shoots, 2 from asymptomatic raspberry leaves, and 4 from symptomatic blackberry shoots. Additionally, eight raspberry strains, isolated earlier from two similar outbreaks, were included in the study. Pathogenicity of the strains was confirmed on detached raspberry and blackberry shoots by reproducing the symptoms of natural infection. The strains were Gram-negative, fluorescent on King's medium B, ice nucleation positive, and utilized glucose oxidatively. All strains were levan positive, oxidase negative, nonpectolytic, arginine dihydrolase negative, and induced hypersensitivity in tobacco leaves (LOPAT + - - - +, group Ia). Furthermore, all strains liquefied gelatin and hydrolyzed aesculin but did not show tyrosinase activity or utilize tartrate (GATTa + + - -). Tentative identification using morphology, LOPAT, GATTa, and ice-nucleating ability tests suggested that isolated strains belong to . The gene associated with syringomycin production was detected in all strains. DNA fingerprints with REP, ERIC, and BOX primers generated identical profiles for 29 strains, except for strain KBI 222, which showed a unique genomic fingerprint. In all, 9 of 10 selected strains exhibited identical sequences of four housekeeping genes: , , , and . Five nucleotide polymorphisms were found in strain KBI 222 at the gene locus only. In the phylogenetic tree based on a concatenated sequence of all four housekeeping genes, strains clustered within phylogroup 2 (i.e., genomospecies 1) of the species complex, with pathotype strains of pv. and pv. as their closest relatives. There was no correlation between genotype and geographic origin, particular outbreak, host, or cultivar.
2016年5月期间，在塞尔维亚的几个树莓和黑莓种植园中观察到严重的枯萎症状。总共分离出22个菌株：16个来自有症状的树莓嫩枝，2个来自无症状的树莓叶片，4个来自有症状的黑莓嫩枝。此外，从之前两次类似疫情中分离出的8个树莓菌株也被纳入研究。通过再现自然感染症状，在离体的树莓和黑莓嫩枝上证实了这些菌株的致病性。这些菌株革兰氏阴性，在King氏培养基B上产生荧光，冰核形成呈阳性，并且以氧化方式利用葡萄糖。所有菌株levan呈阳性，氧化酶阴性，不分解果胶，精氨酸双水解酶阴性，并且在烟草叶片中诱导过敏反应（LOPAT + - - - +，Ia组）。此外，所有菌株使明胶液化并水解七叶苷，但不显示酪氨酸酶活性或利用酒石酸盐（GATTa + + - -）。使用形态学、LOPAT、GATTa和冰核形成能力测试进行的初步鉴定表明，分离出的菌株属于。在所有菌株中均检测到与丁香霉素产生相关的基因。用REP、ERIC和BOX引物进行的DNA指纹图谱分析显示，除菌株KBI 222外，29个菌株产生了相同的图谱，菌株KBI 222显示出独特的基因组指纹。总共，10个选定菌株中的9个在四个管家基因（、、、和）上表现出相同的序列。仅在菌株KBI 222的基因座上发现了5个核苷酸多态性。在基于所有四个管家基因的串联序列构建的系统发育树中，菌株聚集在物种复合体的phylogroup 2（即基因组种1）内，与pv. 和pv. 的致病型菌株是其最亲近的亲属。基因型与地理起源、特定疫情、宿主或品种之间没有相关性。
