In 2014, bark cankers were observed on Caucasian alder (Alnus subcordata) trees in Iran. The disease was characterized by a dark watery liquid often exuding from longitudinal cankers in the bark of the tree trunks which stained the surface. Symptomatic tissue from A. subcordata was sampled from a number of sites in the Mazandaran province. Isolations were performed on nutrient agar supplemented with sucrose (SNA) and yielded bacterial colonies that were uniform, round and whitish. The bacterial strains isolated from alder trees in Iran were similar to Brenneria alni based on phenotypic and genotypic (nucleotide sequences of the 16S rRNA, and housekeeping genes gyrB, and infB) characteristics. The pathogenicity of the representative strains was determined by inoculating stem pieces of A. subcordata. All tested strains caused longitudinal necrotic lesions 30 days after inoculation and were re‐isolated from this tissue. To our knowledge, this is the first report of the occurrence of B. alni in Iran, and on A. subcordata globally.

中文翻译：

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细囊藻（Brennneria alni），Al木的致​​病菌树皮溃疡

2014年，在伊朗的高加索al木（Alnus subcordata）树上观察到树皮溃疡。该病的特征是深色水状液体经常从树干树皮的纵向溃疡中渗出，使表面变色。从马赞达兰省的许多地点取样了来自皮下土壤杆菌的症状组织。在补充了蔗糖（SNA）的营养琼脂上进行分离，并产生均匀，圆形和发白的细菌菌落。从表皮和基因型（16S rRNA的核苷酸序列，以及管家基因gyrB和infB）特征。代表性菌株的致病性是通过接种黑曲霉茎秆来确定的。接种后30天，所有测试菌株均引起纵向坏死性病变，并从该组织中重新分离出来。据我们所知，这是关于伊朗B. alni发生以及全球A. subcordata的首次报道。