Ralstonia solanacearum sensu lato causes bacterial wilt in many agronomic crops and tree species economically important worldwide. It is a species complex that has been divided into phylotypes and sequevars, commonly related to geographic distribution. Knowledge of the phylotype composition and genetic variability in populations of this phytopathogenic bacterium is useful for implementing effective control measures. In a survey conducted in 2019, six bacterial strains were obtained from wilted Eucalyptus urophylla trees in plantations located in the municipality of Dom Eliseu, Pará state, Brazil. Multiplex PCR based on the internal transcribed spacer (ITS) indicated that the bacterial strains belonged to two different species, namely R. pseudosolanacearum (phylotype I) and R. solanacearum (phylotype II). In a phylogenetic analysis, the nucleotide sequence of the endoglucanase (egl) gene from eucalypt strains of phylotype I clustered together with sequevar 18 sequences from GenBank. Separation of the strains into two different species was confirmed by repetitive element palindromic PCR (rep‐PCR). Pathogenicity tests demonstrated that the R. solanacearum and R. pseudosolanacearum strains recovered from E. urophylla cause disease in both tomato and eucalypt plants. Until now, only R. solanacearum (Phylotype II) has been reported causing wilt symptoms on Eucalyptus spp. in Brazil. Therefore, the presence of R. pseudosolanacearum and a need for better understanding of its genetic and aggressiveness variability as well as possible differences between the two species should be considered in breeding programmes aimed at the deployment of host resistance.

中文翻译：

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感染桉树的拟南芥Ralstonia pseudosolanacearum的检测和鉴定。在巴西

青枯雷尔氏菌会在全球范围内具有重要经济意义的许多农作物和树木中引起细菌枯萎。它是一种物种复合体，通常分为地理分布和系统型。了解这种植物致病细菌种群的系统型组成和遗传变异性对于实施有效的控制措施很有用。在2019年进行的一项调查中，从位于巴西帕拉州Dom Eliseu市的人工林中枯萎的尾叶桉（Eucalyptus urophylla）树中获得了六种细菌菌株。基于内部转录间隔子（ITS）的多重PCR表明该细菌菌株属于两个不同的物种，即假单胞菌。（系统型I）和青枯菌（系统型II）。在系统发育分析中，来自I型桉树菌株的内切葡聚糖酶（egl）基因的核苷酸序列与GenBank的Sequevar 18序列聚在一起。通过重复元素回文PCR（rep-PCR）将菌株分离为两个不同的物种。致病性测试表明，从尾叶大肠杆菌（E. urophylla）回收的青枯菌和拟茄霉（R. pseudosolanacearum）菌株在番茄和桉树植物中均引起病害。迄今为止，仅报道了茄形青枯菌（Phylotype II）引起桉树属枯萎症状。在巴西。因此，存在假单胞菌（R. pseudosolanacearum）以及需要对其遗传和侵略性变异以及两个物种之间可能存在的差异有更好的了解的目的，应在旨在部署宿主抗性的育种计划中考虑。