Burkholderia dipogonis sp. nov., isolated from root nodules of Dipogon lignosus in New Zealand and Western Australia.

Abstract

Seven strains, ICMP 19430ᵀ, ICMP 19429, ICMP 19431, WSM4637, WSM4638, WSM4639 and WSM4640, were isolated from nitrogen-fixing nodules on roots of the invasive South African legume Dipogon lignosus (subfamily Papilionoideae, tribe Phaseoleae) in New Zealand and Western Australia, and their taxonomic positions were investigated by using a polyphasic approach. All seven strains grew at 10–37 °C (optimum, 25–30 °C), at pH 4.0–9.0 (optimum, pH 6.0–7.0) and with 0–2 % (w/v) NaCl (optimum growth in the absence of NaCl). On the basis of 16S rRNA gene sequence analysis, the strains showed 99.0–99.5 % sequence similarity to the closest type strain, Burkholderia phytofirmans PsJNT, and 98.4–99.7 % sequence similarity to Burkholderia caledonica LMG 19076ᵀ. The predominant fatty acids were C₁₈ : ₁ω7c (21.0 % of the total fatty acids in strain ICMP 19430ᵀ), C₁₆ : ₀ (19.1 %), C₁₇ : ₀ cyclo (18.9 %), summed feature 3 (C₁₆ : 1ω7c and/or C₁₆ : ₁ω6c; 10.7 %) and C₁₉ : ₀ cyclo ω8c (7.5 %). The polar lipid profile consisted of a mixture of phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol and several uncharacterized aminophospholipids and phospholipids. The major isoprenoid quinone was Q-8 and the DNA G+C content of strain ICMP 19430ᵀ was 63.2 mol%. The DNA–DNA relatedness of the novel strains with respect to the closest neighbouring members of the genus Burkholderia was 55 % or less. On the basis of 16S rRNA and recA gene sequence similarities and chemotaxonomic and phenotypic data, these strains represent a novel symbiotic species in the genus Burkholderia, for which the name Burkholderia dipogonis sp. nov. is proposed, with the type strain ICMP 19430ᵀ ( = LMG 28415ᵀ = HAMBI 3637ᵀ).