Aureimonas jatrophae sp. nov. and Aureimonas phyllosphaerae sp. nov., leaf-associated bacteria isolated from Jatropha curcas L.

Four orange-pigmented isolates, L7-456, L7-484(T), L9-479 and L9-753(T), originating from surface-sterilized leaf tissues of Jatropha curcas L. cultivars were characterized using a polyphasic taxonomic approach. Phylogenetic analyses based on 16S rRNA gene sequences indicated that all four isolates belong to the genus Aureimonas. In these analyses, strain L7-484(T) appeared to be most closely related to Aureimonas ureilytica 5715S-12(T) (95.7 % sequence identity). The 16S rRNA gene sequences of strains L7-456, L9-479 and L9-753(T) were found to be identical and also shared the highest similarity with A. ureilytica 5715S-12(T) (97.5 %). Both L7-484(T) and L9-753(T) contained Q-10 and Q-9 as predominant ubiquinones and diphosphatidylglycerol, phosphatidylglycerol, phosphatidylcholine, phosphatidylmonomethylethanolamine, phosphatidylethanolamine, phosphatidyldimethylethanolamine, sulfoquinovosyldiacylglycerol and an aminophospholipid as the major polar lipids. C18 : 1ω7c and C16 : 0 were the major fatty acids. Similar to other species in the genus Aureimonas, hydroxylated fatty acids (e.g. C18 : 1 2-OH) and cyclic fatty acids (C19 : 0 cyclo ω8c) were also present. The DNA G+C contents of L7-484(T) and L9-753(T) were 66.1 and 69.4 mol%, respectively. Strains L7-484(T) and L9-753(T) exhibited less than 40 % DNA-DNA hybridization both between themselves and to A. ureilytica KACC 11607(T). Our results support the proposal that strain L7-484(T) represents a novel species within the genus Aureimonas, for which the name Aureimonas jatrophae sp. nov. is proposed, and that strains L9-753(T), L7-456 ( = KACC 16229  = DSM 25023) and L9-479 ( = KACC 16228  = DSM 25024) represent a second novel species within the genus, for which the name Aureimonas phyllosphaerae sp. nov. is proposed. The type strains of Aureimonas jatrophae sp. nov. and Aureimonas phyllosphaerae sp. nov. are respectively L7-484(T) ( = KACC 16230(T)  = DSM 25025(T)) and L9-753(T) ( = KACC 16231(T)  = DSM 25026(T)).

Phylogenetic diversity of thermophilic actinomycetes and Thermoactinomyces spp. isolated from mushroom composts in Korea based on 16S rRNA gene sequence analysis.

Forty one strains isolated from 21 samples of various mushroom composts in Korea were analyzed by 16S rRNA gene sequencing to investigate the phylogenetic diversity of thermophilic actinomycetes. The 25 strains of thermophilic actinomycete isolates were related to the five genera, Pseudonocardia, Saccharomonospora, Saccharopolyspora, Streptomyces, and Thermobifida, within the order Actinomycetales, and 16 strains were classified into the genus Thermoactinomyces within the family Bacillaceae. Most of 41 isolates were encompassed by two genera, Streptomyces and Thermoactinomyces, that were isolated mainly in composts prepared from waste cotton and hay, respectively. Among them, M104 and M109 were placed in distinct taxonomic positions although these strains formed phylogenetic lineages related to the genus Streptomyces and to the family Streptosporangiaceae, respectively. Therefore, a phenetic and genetic characterization of these strains will be needed to pinpoint their taxonomic position.