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).

Acinetobacter puyangensis sp. nov., isolated from the healthy and diseased part of Populus xeuramericana canker bark.

Two Gram-negative, non-motile, rod-shaped strains, BQ4-1(T) and NHI3-2, isolated respectively from the healthy and diseased part of Populus ×euramericana canker bark, were characterized using a polyphasic approach. Chemotaxonomic characterization supported the inclusion of the two strains in the genus Acinetobacter, with genomic DNA G+C contents (42.5-43 mol%) within the range observed for this genus (38-47 mol%) and 9-octadecenoic acid (C18 : 1ω9c, 39.87 %), hexadecanoic acid (C16 : 0, 11.26 %) and summed feature 3 (comprising C16 : 1ω7c/C16 : 1ω6c, 18.90 %) as major fatty acids. Phylogenetic analysis based on 16S rRNA, rpoB and gyrB gene sequences revealed that strains BQ4-1(T) and NHI3 did not cluster with any species with validly published names, and formed a distinct cluster with 99-100 % bootstrap support on three phylogenetic trees within the genus Acinetobacter. Acid was not produced from d-glucose, and haemolysis was not observed on agar media supplemented with sheep erythrocytes. On the basis of phenotypic, genotypic and phylogenetic characteristics, the two strains are considered to represent a novel species of the genus Acinetobacter, for which the name Acinetobacter puyangensis sp. nov. is proposed. The type strain is BQ4-1(T) (= CFCC 10780(T) = JCM 18011(T)).