Ralstonia solanacearum species complex is the most destructive and economically important bacterial pathogen of many plant species around the world. It is a particular constraint to the production of the solanaceous vegetables such as tomato, chilli pepper and African eggplant in West Africa. Its broad host range, ability to survive in the soil for long periods and ability to sustain latent infection, make it difficult to control. Identification, characterization and mapping the distribution of the causal Ralstonia spp. strains are necessary to help design effective control strategies. Wilted tomato, African eggplant and pepper plant samples were collected from fields in different regions of Mali. The causal bacterial strains were isolated from the samples and all were identified as Ralstonia pseudosolanacearum. Multiplex PCR using four phylotype specific primer pairs identified the presence of phylotype I strains distributed across all the vegetable production areas whereas phylotype III strains were limited to areas of Sikasso, Koulikoro and Segou to the south and east of Bamako city. Phylogenetic analysis of part of the conserved endoglucanase virulence gene sequences revealed four sequevars with most phylotype I strains identified as sequevars 46 and 31 with only a few as sequevar 14 and one sequevar 18. The phylotype III strains were all in the sequevar 23–48 group. Pathogenicity testing of a selected subset of the strains isolated in Mali showed them all to be pathogenic to the susceptible tomato cultivar Roma. To our knowledge, this is the first study on the molecular diversity within the Ralstonia spp. complex in Mali. This information is important for developing wilt management strategies including breeding for resistance and specifying quarantine restrictions.

中文翻译：

---

Ralstonia spp 的鉴定和表征。导致马里蔬菜青枯病

Ralstonia solanacearum 物种复合体是世界上许多植物物种中最具破坏性和经济重要性的细菌病原体。特别是西非番茄、辣椒、非洲茄子等茄科蔬菜的生产受到限制。其广泛的寄主范围、在土壤中长期存活的能力和持续潜伏感染的能力，使其难以控制。鉴定、表征和绘制因果 Ralstonia spp 的分布。菌株对于帮助设计有效的控制策略是必要的。从马里不同地区的田间收集枯萎的番茄、非洲茄子和辣椒植物样本。从样品中分离出致病菌株，均被鉴定为Ralstonia pseudosolanacearum。使用四个系统发育特异性引物对的多重 PCR 确定存在分布在所有蔬菜生产区的系统发育 I 菌株，而系统发育 III 菌株仅限于巴马科市南部和东部的 Sikasso、Koulikoro 和 Segou 地区。部分保守的内切葡聚糖酶毒力基因序列的系统发育分析揭示了4个sequevars，其中大多数系统发育型I菌株被鉴定为sequevars 46和31，只有少数为sequevar 14和一个sequevar 18。系统发育型III菌株均在sequevar 23-48组. 对马里分离的选定菌株亚群的致病性测试表明，它们都对易感番茄栽培品种 Roma 具有致病性。据我们所知，这是对 Ralstonia spp 内分子多样性的第一项研究。复杂的马里。