Oak decline syndrome is characterized by periodic occurrences of decline and death of oaks over widespread areas. An outbreak of a new emerging disease on oak trees was reported in the Hyrcanian forest of Iran (Mazandaran and Golestan provinces) that showed stem bleeding and canker symptoms. Bacterial isolates were characterized through biochemical and physiological tests, protein electrophoresis, DNA fingerprinting (rep‐PCR, ERIC and BOX primers) and sequencing of 16S rRNA and MLSA (multilocus sequencing analysis) for housekeeping genes (gyrB, infB and atpD). A complex community of the genus Brenneria spp. (Brenneria goodwinii, Brenneria roseae subsp. roseae, Brenneria sp. and Brenneria nigrifluens) and a few isolates in the genus Gibbsiella were identified as major groups involved. Isolate differentiation was more accurate using concatenated partial gene sequences within the main groups. All bacterial isolates showed hypersensitivity reactions (HR) on Pelargonium leaves (Pelargonium × hortorum). Pathogenicity studies of different Brenneria and Gibbsiella strains revealed that they have potential to cause the disease in oak seedlings and devastating oak canker and stem bleeding symptoms in northern Iran. Due to the presence of several potentially pathogenic agent(s) associated with the oak decline, identification of the principal agent(s) is of major interest. To our knowledge, this is the first report of potentially pathogenic bacteria associated with oak bleeding and canker in Iran.

中文翻译：

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伊朗北部与患病橡树有关的细菌菌株的鉴定和表征

橡树衰落综合症的特征是在广泛的地区周期性地发生橡树衰落和死亡。伊朗Hycancan森林（Mazandaran和Golestan省）据报道在橡树上爆发了一种新出现的疾病，显示出茎干出血和溃疡病症状。细菌分离物通过生化和生理学测试，蛋白质电泳，DNA指纹图谱（rep-PCR，ERIC和BOX引物）以及管家基因（gyrB，infB和atpD）的16S rRNA和MLSA测序（多位点测序分析）进行表征。Brenneria spp属的复杂群落。（Brenneria goodwinii，Brenneria roseae亚种。roseae，Brenneria SP。和Brenneria nigrifluens）和属少数株Gibbsiella被认定为参与的主要群体。在主要人群中使用串联的部分基因序列进行分离分化更为准确。所有细菌分离物均对天竺葵叶片（天竺葵 ×  hortorum）表现出超敏反应（HR ）。不同的布雷氏菌和吉布氏菌的致病性研究菌株显示它们有可能在伊朗北部的橡树幼苗中引起该病，并破坏橡树溃疡和茎出血的症状。由于存在与橡树衰落有关的几种潜在病原体，因此主要试剂的鉴定尤为重要。据我们所知，这是有关伊朗橡木出血和溃疡病的潜在致病菌的首次报道。