Sinorhodobacter populi sp. nov., isolated from the symptomatic bark tissue of Populus × euramericana canker.

We isolated five novel bacterial strains from symptomatic bark tissue of Populus × euramericana canker that were Gram-stain-negative, non-motile, aerobic oxidase-negative and catalase-positive. Growth occurred at 10-41 °C and at pH 5.0-7.0, with optimum growth at 30 °C and pH 7.0. Additionally, growth occurred in conditions of 0-5 % (w/v) salinity, but not above 7 % NaCl. The 16S rRNA gene sequences of the novel strains shared the highest similarity with Sinorhodobacter ferrireducens SgZ-3T (97.1 %). The average nucleotide identity values between the novel strains and two type strains (S.inorhodobacter ferrireducens CCTCC AB2012026T and 'Sinorhodobacter hungdaonensis' CGMCC 1.12963T) were 78.4-78.9 %, which were lower than the proposed species boundary cut-off (95-96 %). The main polar lipids were phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol, an unidentified lipid and phosphatidylcholine. The main respiratory quinone was Q-10, and major fatty acids were C18 : 1ω7c and/or C18 : 1ω6c. Based on data from a polyphasic taxonomy study, the novel strains represent a novel species of the genus Sinorhodobacter, for which the name Sinorhodobacter populi sp. nov. is proposed. The type strain is sk2b1T (=CFCC 14580T=KCTC 52802T).

Ancrocorticia populi gen. nov., sp. nov, isolated from the symptomatic bark of Populus × euramericana canker.

A Gram-staining positive facultative anaerobic, non-motile strain, sk1b4T , was isolated from canker of symptomatic bark tissue of a Populus × euramericana. 16S rRNA gene sequence analyses showed that strain sk1b4T shared the highest similarity with Arcanobacterium phocisimile (94.1%). Within the phylogenetic tree, the novel isolate formed a distinct branch from Actinobaculum, Arcanobacterium, and Trueperella. The percentage of conserved proteins calculated from genomic sequence indicated a low level of relatedness between the novel strain and its phylogenetic neighbors. Growth of the novel strain occurred at temperatures between 10 and 41°C, and within a pH range of 6.0-9.0; optimal growth occurred at 30°C and at pH 6.0-9.0. Growth also occurred within a NaCl concentration of 1%-5% (w/v). The major fatty acids of the strain were C14:0 , C16:0 , and C18:1 ω9c, and major polar lipids were glycolipid, phosphatidylinositol mannoside, phospholipid, diphosphatidylglycerol, and phosphatidylglycerol. Respiratory quinone was absent. On the basis of phenotypic and genotypic characteristics, we propose that the novel isolate should be classified as a novel species in a new genus: Ancrocorticia populi gen. nov., sp. nov. The type strain is sk1b4T (=CFCC 14564T = KCTC 39919T ).

Sphingobacterium corticis sp. nov., isolated from bark of Populus × euramericana.

A Gram-stain negative, aerobic, non-motile bacterial strain, 23D10-4-9T, was isolated from symptomatic canker bark tissue of Populus × euramericana. The isolate grew between 4 and 35 °C, with optimal growth occurring at 25 °C. The species was positive for catalase and negative for oxidase activity. Nitrate was not reduced to nitrite. It showed activities toward ß-galactosidase and ß-glucosidase. Citrate was not utilized. Acid was produced from d-glucose. The major fatty acids were iso-C15 : 0, C16 : 1ω7c and iso-C17 : 0 3-OH. The main polar lipid profiles of the novel isolate included phosphatidylethanolamine, phospholipids and seven unknown lipids. The predominant menaquinone of the novel isolate was MK-7. The DNA G+C content was 40.6 mol%. 16S rRNA gene data revealed that the novel isolate shares the greatest sequence similarity with Sphingobacterium populi 7Y-4T (96.1 %). Based on phenotypic and genotypic characteristics, the isolate represents a novel species within the genus Sphingobacterium, for which the name Sphingobacteriumcorticis sp. nov. is proposed. The type strain is 23D10-4-9T (=CFCC 12640T=KCTC 42248T).