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

Seven strains, ICMP 19430T, ICMP 19429, ICMP 19431, WSM4637, WSM4638, WSM4639 and WSM4640 were isolated from nitrogen-fixing nodules on the 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 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, 0 % [w/v]). On the basis of 16S rRNA gene sequence analysis, the strains showed 99.0-99.5 % sequence similarity to the closest species Burkholderia phytofirmans PsJNT and 98.4-99.7 % sequence similarity to Burkholderia caledonica LMG 19076T. The predominant fatty acids were C18:1 7c (21.0 %), C16:0 (19.1 %), C17:0 cyclo (18.9 %), summed feature 3 (comprising C16:1 7c and/or C16:1 6c; 10.7 %) and C19:0 cyclo 8c (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 was 63.2 mol%. The DNA-DNA relatedness of the novel strains with respect to the closest neighbouring Burkholderia species was 55 % or less. On the basis of 16S rRNA and recA gene sequence similarities, and on 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).