Rhizobium quercicola sp. nov., isolated from the leaf of Quercus variablis in China.

Strain DKSPLA3T, a novel Gram-negative, catalase-positive, oxidase-positive, non-spore-forming, aerobic, non-nitrogen-fixing, non-motile bacterium was isolated from Quercus variablis leaf, in Zunyi, Guizhou, China. Growth occurred at 4-37 °C (optimum 28 °C), pH 4.0-9.0 (optimum pH 7.0) and up to 4.0% (w/v) NaCl (optimum under 2.0%, w/v). Phylogeny based on 16S rRNA gene indicated that strain DKSPLA3T was a novel species in the genus Rhizobium, which was supported by average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) values. The predominant fatty acids of strain DKSPLA3T were C16:0, C18:1 ω7c and/or C18:1 ω6c and C18:1 ω7c 11-methyl. The major respiratory quinone was Q-10. Major polar lipids were diphosphatidyl glycerol (DPG), phosphatidyl glycerol (PG), phosphatidylethanolamine (PE), phosphatidylmonomethylethanolamine (PME), phosphatidylcholine (PC), two unidentified phospholipids (PL) and nine unidentified lipids (L). The genomic G + C content was 64.47 mol%. Based on the phenotypic, phylogenetic and genotypic data, DKSPLA3T should be classified as a novel species in the genus Rhizobium, for which the name Rhizobium quercicola sp. nov. (KCTC 82843T = CFCC 16,707T) is proposed.

Reclassification of 11 Members of the Family Rhodobacteraceae at Genus and Species Levels and Proposal of Pseudogemmobacter hezensis sp. nov.

A novel Gram-stain-negative, aerobic, motile bacterial strain, D13-10-4-6T, was isolated from the bark sample of Populus × euramericana. The strain could grow at 15-35°C, at pH 6-10 and in 0-4% (w/v) NaCl, and the strain tested positive for oxidase and catalase activities. The main polar lipids were phosphatidylmonomethylethanolamine, diphosphatidylglycerol, phosphatidylglycerol, and phosphatidylethanolamine. The main respiratory quinone was Q-10, and the predominant fatty acid was C18:1 ω7c. The phylogenetic analyses showed that the strain belonged to the genus Pseudogemmobacter of the family Rhodobacteraceae. The family Rhodobacteraceae is an ecologically diverse group that includes bacteria from aquatic to terrestrial ecosystems. As a consequence, the classification of the family Rhodobacteraceae is difficult, not least when the early taxonomy work relied heavily on 16S rRNA gene analysis. Recently, the taxonomic status of many members of the family has been revised based on the genome analysis; however, there are still some classification conflicts due to the lack of genome sequences and parallel publication time. In this study, phylogenetic trees based on 16S rRNA gene, gyrB gene, and 120 concatenated proteins, the average amino acid identity (AAI) and percentage of conserved proteins (POCP) have been used for the analysis of strain D13-10-4-6T and other members of 15 genera within the family to further clarify their taxonomic relationships. For the data of phylogeny, AAI, and POCP, the taxonomic proposals are (1) reclassification of Rhodobacter tardus as the type species of a novel genus, Stagnihabitans gen. nov., as Stagnihabitans tardus comb. nov.; (2) reclassification of Tabrizicola alkalilacus, Tabrizicola sediminis, Tabrizicola algicola into a novel genus, Pseudotabrizicola gen. nov., as Pseudotabrizicola alkalilacus comb. nov., Pseudotabrizicola sediminis comb. nov., Pseudotabrizicola algicola comb. nov.; (3) reclassification of Rhodobacter sediminicola into the genus Cereibacter as Cereibacter sediminicola comb. nov.; (4) reclassification of Rhodobacter flagellatus, Rhodobacter thermarum, and Xinfangfangia soli into the genus Tabrizicola as Tabrizicola flagellatus comb. nov., Tabrizicola thermarum comb. Nov., and Tabrizicola soli comb. nov.; (5) reclassification of Xinfangfangia humi into the genus Pseudogemmobacter as Pseudogemmobacter humicola comb. nov.; (6) classification of strain D13-10-4-6T as a novel species of the genus Pseudogemmobacter, for which the name P. hezensis sp. nov. is proposed, the type strain is D13-10-4-6T (= CFCC 12033T = KCTC 82215T).

Morphology and Phylogeny of Gnomoniopsis (Gnomoniaceae, Diaporthales) from Fagaceae Leaves in China.

Gnomoniopsis (Gnomoniaceae, Diaporthales) is a well-classified genus inhabiting leaves, branches and fruits of the hosts in three plant families, namely Fagaceae, Onagraceae and Rosaceae. In the present study, eighteen Gnomoniopsis isolates were obtained from diseased leaves of Fagaceae hosts collected from Fujian, Guangdong, Hainan, Henan, Jiangxi and Shaanxi provinces in China. Morphology from the cultures and phylogeny based on the 5.8S nuclear ribosomal DNA gene with the two flanking internally transcribed spacer (ITS) regions, the translation elongation factor 1-alpha (tef1) and the beta-tubulin (tub2) genes were employed to identify these isolates. As a result, seven species were revealed, viz. Gnomoniopsis castanopsidis, G. fagacearum, G. guangdongensis, G. hainanensis, G. rossmaniae and G. silvicola spp. nov, as well as a known species G. daii. In addition, G. daii was firstly reported on the host Quercus aliena.

Pseudomonas quercus sp. nov, associated with leaf spot disease of Quercus mongolica.

Two Gram-negative, aerobic, motile bacteria strains were isolated from leaf spot disease of Quercus mongolica. Strain hsmgli-8T has 99.86 % 16S rRNA gene sequence similarity to LY10J, and the highest 16S rRNA gene sequence similarity to Pseudomonas cerasi 58T (97.2 %), then Pseudomonas ficuserectae JCM 2400T (97.18 %), Pseudomonas meliae CFBP 3225T, Pseudomonas tremae CFBP 6111T and Pseudomonas congelans DSM 14939T (all 97.12 %), and less than 97.1 % similarity to other recognized species. In phylogenetic trees based on 16S rRNA gene and multilocus sequence data, the two novel strains form a separate branch, indicating that they do not belong to any Pseudomonas group and subgroup, and should belong to a novel species within the genus Pseudomonas. This assertion is also supported by the results of genome average nucleotide identity analysis. The major fatty acids are C16 : 0, C18 : 1 ω7c and/or C18 : 1 ω6c, C16 : 1 ω7c and/or C16 : 1 ω6c. Polar lipids include phosphatidylethanolamine, diphosphatidylglycerol, phosphatidylglycerol, aminolipid and seven uncharacterized phospholipids. The predominant respiratory quinone is Q-9. The DNA G+C content is 59.45-59.50 mol%. Based on these data, we propose that the two novel strains should be assigned as a novel species within the genus Pseudomonas. We propose that the novel strains be named Pseudomonas quercus sp. nov. The type strain is hsmgli-8T (=CFCC 15739T=LMG 31544T).

Affinibrenneria salicis gen. nov. sp. nov. isolated from Salix matsudana bark canker.

L3-3HAT, a Gram-negative-staining, facultatively anaerobic, motile bacterial strain, was isolated from the symptomatic bark of Salix matsudana canker in China. 16S rRNA gene analysis revealed that the novel strain shares the highest sequence similarity with Brenneria goodwinii FRB141T (95.5%). In phylogenetic trees based on four housekeeping genes (gyrB, rpoB, atpD, and infB) and the 16S rRNA gene sequence, the novel strain formed a separate branch from the five genera of the family Pectobacteriaceae (Lonsdalea, Brenneria, Dickeya, Pectobacterium, and Sodalis), suggesting that the novel strain should belong to a novel species of a novel genus within the family Pectobacteriaceae. The result was also supported by phylogenomics, amino acid identity and average nucleotide identity. The major fatty acids were C14:0, C16:0, C17:0 cyclo, and C19:0 cyclo É·8c. Genome analysis showed that the novel strain has a large genome (5.89 Mb) with 5,052 coding genes, including 181 virulence genes by searching the pathogen-host interactions database (PHI-base), indicating that the novel strain is a potential pathogen of plants and animals. Based on phenotypic and genotypic characteristics, the L3-3HAT strain represents a novel species of a novel genus in the Pectobacteriaceae family, for which the name Affinibrenneria salicis gen nov. sp. nov. is proposed. The strain type is L3-3HAT (= CFCC 15588T = LMG 31209T).

Noviherbaspirillum aerium sp. nov., isolated from air.

A Gram-stain-negative, strictly aerobic, non-spore-forming, rod-shaped, motile with polar flagella and pale-orange bacterium, designated strain 122213-3T, was isolated from air, collected at the foot of the Xiangshan Mountain, located in Beijing, PR China. Optimal growth occurred at 28 °C, at pH 7 and in the presence of 0-1 % (w/v) NaCl. Phylogenetic analyses based on 16S rRNA gene sequences revealed that 122213-3T clustered with species of the genus Noviherbaspirillum and formed a distinct sublineage, showing highest similarities to Noviherbaspirillum malthae CC-AFH3T (96.88 %), Noviherbaspirillum massiliense JC206T (95.78 %) and Noviherbaspirillum aurantiacum SUEMI08T (95.78 %). The predominant cellular fatty acids were summed feature 3 (C16 : 1 ω6c and/or C16 : 1 ω7c), summed feature 8 (C18 : 1 ω7c and/or C18 : 1 ω6c) and C16 : 0. The predominant quinone was ubiquinone 8 (Q-8). The polar lipids comprised phosphatidylethanolamine, phosphatidylglycerol, unidentified phospholipid and two unidentified polar lipids. The polyamine pattern showed the presence of putrescine as the major polyamine, with minor amounts of 2-hydroxyputrescine. The DNA G+C content was 60.1 mol%. The phylogenetic analysis and physiological and biochemical data showed that strain 122213-3T should be classified as representing a novel species in the genus Noviherbaspirillum, for which the name Noviherbaspirillum aerium sp. nov. is proposed. The type strain of N. aerium is 122213-3T (=CFCC 14286T=LMG 30131T).

Sphingomonas corticis sp. nov., and Sphingobacterium corticibacterium sp. nov., from bark canker.

Two Gram-stain-negative, aerobic, non-motile bacterial strains, 36D10-4-7T and 30C10-4-7T, were isolated from bark canker tissue of Populus × euramericana, respectively. 16S rRNA gene sequence analysis revealed that strain 36D10-4-7T shows 98.0 % sequence similarity to Sphingomonas adhaesiva DSM 7418T, and strain 30C10-4-7T shows highest sequence similarity to Sphingobacterium arenae H-12T (95.6 %). Average nucleotide identity analysis indicates that strain 36D10-4-7T is a novel member different from recognized species in the genus Sphingomonas. The main fatty acids and respiratory quinone detected in strain 36D10-4-7T are C18 : 1 ω7c and/or C18 : 1 ω6c and Q-10, respectively. The polar lipids are diphosphatidylglycerol, phosphatidylcholine, phosphatidylglycerol, aminolipid, phosphatidylethanolamine, sphingoglycolipid, two uncharacterized phospholipids and two uncharacterized lipids. For strain 30C10-4-7T, the major fatty acids and menaquinone are iso-C15 : 0, C16 : 1 ω7c and/or C16 : 1 ω6c and iso-C17 : 0 3-OH and MK-7, respectively. The polar lipid profile includes phosphatidylethanolamine, phospholipids, two aminophospholipids and six unidentified lipids. Based on phenotypic and genotypic characteristics, these two strains represent two novel species within the genera Sphingomonas and Sphingobacterium. The name Sphingomonas corticis sp. nov. (type strain 36D10-4-7T=CFCC 13112T=KCTC 52799T) and Sphingobacterium corticibacterium sp. nov. (type strain 30C10-4-7T=CFCC 13069T=KCTC 52797T) are proposed.

Stenotrophomonas cyclobalanopsidis sp. nov., isolated from the leaf spot disease of Cyclobalanopsis patelliformis.

A Gram-negative, facultatively anaerobic, motile bacterial strain, TPQG1-4T, was isolated from the leaf of Cyclobalanopsis patelliformis with spot disease. The isolate was investigated using the polyphasic taxonomic approach. 16S rRNA gene sequencing and analyzing revealed that the novel strain shares the highest sequence similarity with Stenotrophomonas lactitubi M15T (99.6%), Stenotrophomonas indicatrix WS40T (99.4%), Stenotrophomonas maltophilia IAM 12423T (99.2%) and Stenotrophomonas pavanii LMG 25348T (99.0%). In phylogenetic trees based on 16S rRNA gene sequences, the novel strain branched independently from other species of Stenotrophomonas. Average nucleotide identity values between the novel isolate and S. lactitubi M15T, S. indicatrix WS40T, S. maltophilia IAM 12423T, S. pavanii LMG 25348T, and Pseudomonas geniculata ATCC 19374T were 87.2%, 87.3%, 86.3%, 88.0%, and 81.3%, respectively, suggesting the isolate was a novel species of the genus Stenotrophomonas. The DNA G + C content of TPQG1-4T is 67.1 mol%. The major fatty acids were iso-C15:0 (25.4%) and anteiso-C15:0 (17.0%). The polar lipids of TPQG1-4T included phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol, amino phospholipid and phospholipid. Based on phenotypic and genotypic characteristics, the strain represents a novel species in the genus Stenotrophomonas, for which the name Stenotrophomonas cyclobalanopsidis sp. nov. is proposed. The type strain is TPQG1-4T (= CFCC 15341T = LMG 31208T).

Azohydromonas aeria sp. nov., isolated from air.

A grey pink colored bacterium, strain t3-1-3T, was isolated from the air at the foot of the Xiangshan Mountain in Beijing, China. The cells are aerobic, Gram-stain-negative, non-spore-forming, motile and coccoid-rod shaped (0.9-1.2 × 1.9-2.1 µm). Strain t3-1-3T was catalase-positive and oxidase-negative and this strain grew at 4-42°C (optimum 28°C), a pH of 4.0-9.0 (optimum pH 7.0) and under 0-2% (w/v) NaCl (optimum 0-1% NaCl). A phylogenetic analysis based on 16S rRNA gene sequences revealed that strain t3-1-3T was closely related to Azohydromonas riparia UCM-11T (97.4% similarity), followed by Azohydromonas australica G1-2T (96.8%) and Azohydromonas ureilytica UCM-80T (96.7%). The genome of strain t3-1-3T contains 6,895 predicted protein-encoding genes, 8 rRNA genes, 62 tRNA genes and one sRNA gene, as well as five potential biosynthetic gene clusters, including clusters of genes coding for non-ribosomal peptide synthetase (NRPS), bacteriocin and arylpolyene and two clusters of genes for terpene. The predominant cellular fatty acids (> 10.0% of the total) in strain t3-1-3T were summed feature 3 (C16:1ω7c and/or C16:1ω6c, 37.8%), summed feature 8 (C18:1ω7c and/or C18:1ω6c, 29.7%) and C16:0 (17.3%). Strain t3-1-3T contained ubiquinone-8 (Q-8) as the predominant respiratory quinone. The polar lipids of strain t3-1-3T comprised phosphatidyl ethanolamine (PE), phosphatidyl glycerol (PG), diphosphatidyl glycerol (DPG), an unidentified glycolipid (GL), an unidentified aminophospholipid (APL), two unidentified phospholipid (PL1-2) and five unidentified lipid (L1-5). The DNA G + C content of the type strain is 70.3%. The broader range of growth temperature, assimilation of malic acid and trisodium citrate, presence of C18:3ω6c and an unidentified glycolipid and absence of C12:0 2-OH and C16:0iso differentiate strain t3-1-3T from related species. Based on the taxonomic data presented in this study, we suggest that strain t3-1-3T represents a novel species within the genus Azohydromonas, for which the name Azohydromonas aeria sp. nov. is proposed. The type strain of Azohydromonas aeria is t3-1-3T (= CFCC 13393T = LMG 30135T).

Sphingomonas populi sp. nov., isolated from bark of Populus × euramericana.

One Gram-stain-negative, aerobic, motile bacterial strain, 3-7T, was isolated from symptomatic canker bark tissue of Populus × euramericana. 16S rRNA gene sequence data revealed that the novel isolate shared highest similarity with Sphingomonas panacis DCY99T (98.8 %), and <96.5 % sequence similarity with all other species with validly published names. Growth occurred between 15 and 37 °C and at pH 6.0-9.0, and optimal growth occurred at 30 °C and pH 7.0-8.0. Nitrogen was produced from nitrates. The strain was positive for acetoin production and activity of catalase, oxidase, ß-galactosidase, arginine dihydrolase and ß-glucosidase. The major fatty acids were C16 : 0, C18 : 1ω7c and/or C18 : 1ω6c. The polar lipids of the novel isolate included diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, phosphatidylcholine, sphingoglycolipid, glycolipid, two uncharacterized phospholipids and two uncharacterized lipids. The respiratory quinones detected in isolate 3-7T were Q-10 (96.9 %) and Q-9 (3.1 %). The DNA G+C content was 65.1 mol%. Based on phenotypic and genotypic characteristics, the isolate represents a novel species within the genus Sphingomonas, for which the name Sphingomonas populi is proposed. The type strain is 3-7T (=CFCC 11561T=LMG 30138T).

Acetylome analysis of lysine acetylation in the plant pathogenic bacterium Brenneria nigrifluens.

Protein lysine acetylation, a dynamic and reversible posttranslational modification, plays a crucial role in several cellular processes, including cell cycle regulation, metabolism, enzymatic activities, and protein interactions. Brenneria nigrifluens is a pathogen of walnut trees with shallow bark canker and can cause serious disease in walnut trees. Until now, a little has been known about the roles of lysine acetylation in plant pathogenic bacteria. In the present study, the lysine acetylome of B. nigrifluens was determined by high-resolution LC-MS/MS analysis. In total, we identified 1,866 lysine acetylation sites distributed in 737 acetylated proteins. Bioinformatics results indicated that acetylated proteins participate in many different biological functions in B. nigrifluens. Four conserved motifs, namely, LKac , Kac *F, I*Kac , and L*Kac , were identified in this bacterium. Protein interaction network analysis indicated that all kinds of interactions are modulated by protein lysine acetylation. Overall, 12 acetylated proteins were related to the virulence of B. nigrifluens.

Corticimicrobacter populi gen. nov., sp. nov., a member of the family Alcaligenaceae, isolated from symptomatic bark of Populus × euramericana canker.

One Gram-negative aerobic bacterial strain was isolated from the bark tissue of Populus × euramericana and investigated using a polyphasic approach including 16S rRNA gene sequencing and both phenotypic and chemotaxonomic assays. The 16S rRNA gene and housekeeping gene phylogenies suggest that the novel isolate is different from the other genera of the family Alcaligenaceae. The G+C content, major fatty acids, physiological and biochemical data supported the distinctiveness of the novel strain from reference species. The major fatty acids detected in the novel isolate were C16 : 1ω7c and/or C16 : 1ω6c, C16 : 0, C14 : 0 3OH and/or C16 : 1isoI and C18 : 1ω7c. The phospholipid profile of strain d3-2-2T contained diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, aminolipid, aminophospholipid and an unidentified lipid. The quinone of the novel isolate was Q-8. Therefore, based on the data, the strain constitutes a novel species of a novel genus within the family Alcaligenaceae, for which the name Corticimicrobacter populi gen. nov., sp. nov. is proposed. The type strain is 3d-2-2T (=CFCC 11891T=KCTC 52807T).