Lawson cypress (Chamaecyparis lawsoniana), an important landscape tree, is widely planted in gardens and parks throughout Iran. Crown gall disease on Lawson cypress trees was observed in Sari and Juybar Counties, Mazandaran province, northern Iran, in 2017. Isolation from galls on potato dextrose agar (PDA) containing CaCO₃ yielded bacterial colonies, the predominant types of which were purified and selected for characterization. The isolates were Gram‐negative, oxidase positive, able to grow in 2% NaCl and produced 3‐ketolactose. They hydrolysed esculin, casein and arbutin but not starch, gelatin or Tween 80. Two representative isolates were selected for PCR amplification and sequencing of DNA gyrase subunit B (gyrB) gene. In the phylogenetic tree based on the partial sequence of the gyrB gene, isolates KH1 and KH2 clustered with Agrobacterium pusense. The pathogenicity of all isolates was confirmed by inoculation on Jimsonweed (Datura stramonium) and carrot discs (Daucus carota). Confirmation of the presence of genes involved in pathogenicity was made by performing PCR with the virD2A/virD2C and VCF/VCR primer pairs which resulted in amplification of the expected 224 and 730 bp fragments in all studied isolates, respectively. A. pusense was therefore identified as the causal agent of crown and stem gall of Lawson cypress. This appears to be the first report on the natural occurrence of crown gall disease on Lawson cypress and the first record of a plant disease caused by A. pusense.

中文翻译：

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朴农杆菌，一种新的从Lawson柏中分离出的诱导植物肿瘤的病原体

劳森柏（Chamaecyparis lawsoniana）是一棵重要的景观树，广泛种植在伊朗各地的花园和公园中。2017年，在伊朗北部Mazandaran省的Sari和Juybar县观察到Lawson柏树上的冠gall病。从gall汁中分离含CaCO _3的马铃薯葡萄糖琼脂（PDA）产生细菌菌落，主要菌落经过纯化和选择。用于表征。分离株为革兰氏阴性，氧化酶阳性，能够在2％NaCl中生长并产生3-酮基乳糖。他们水解了七叶树素，酪蛋白和熊果苷，但未水解淀粉，明胶或吐温80。选择了两个代表性的分离物用于PCR扩增和DNA旋转酶亚基B（gyr）的测序。B）基因。在基于gyr B基因的部分序列的系统发育树中，分离到与农杆菌结合的KH1和KH2 。通过接种金森草（Datura stramonium）和胡萝卜盘（Daucus carota）确认了所有分离株的致病性。通过用virD2A / virD2C和VCF / VCR引物对进行PCR来确认与致病性有关的基因的存在，从而分别扩增了所有研究菌株中预期的224和730 bp片段。us因此被确定为劳森柏树冠和茎stem的病因。这似乎是关于Lawson柏自然发生冠胆病的第一份报告，也是由普氏杆菌引起的植物病害的第一份记录。