scholarly journals Characterization, Phylogenetic Analyses, and Pathogenicity of Enterobacter cloacae on Rice Seedlings in Heilongjiang Province, China

Plant Disease ◽  
2020 ◽  
Vol 104 (6) ◽  
pp. 1601-1609
Author(s):  
Peng Cao ◽  
Chenxu Li ◽  
Kefei Tan ◽  
Chuanzeng Liu ◽  
Xi Xu ◽  
...  

Rice is used as a staple food in different areas of world, especially in China. In recent years, rice seedlings have been affected seriously by symptoms resembling bacterial palea browning (BPB) in Heilongjiang Province. To isolate and identify the pathogenic bacteria responsible for the disease, 40 bacterial strains were isolated from diseased rice seedlings collected from the four major accumulative-temperature zones of rice fields cultivated in Heilongjiang Province, and these were identified as 13 species based on morphological characteristics and 16S ribosomal RNA (rRNA) gene sequences. Inoculation of all the isolates on healthy rice seedlings showed that the nine Enterobacter cloacae isolates were the pathogens causing typical symptoms of BPB, including yellowing to pale browning, stunting, withering, drying, and death. Moreover, the nine E. cloacae isolates could also cause symptoms of bacterial disease on the seedlings of soybean (Glycine max), maize (Zea mays L.), and tomato (Solanum lycopersicum). Phylogenetic analysis based on the 16S rRNA gene sequences and phenotypic and biochemical characteristics indicated that these nine pathogenic isolates were E. cloacae. In addition, analysis of the sequences of four housekeeping genes (rpoB, gyrB, infB, and atpD) from the selected strain SD4L also assigned the strain to E. cloacae. Therefore, E. cloacae is the pathogen causing disease of rice seedlings in Heilongjiang Province, which we propose to classify as a form of BPB. To the best of our knowledge, this is the first study to identify E. cloacae as a causal agent of BPB in rice.

2006 ◽  
Vol 56 (5) ◽  
pp. 1013-1018 ◽  
Author(s):  
Bénédicte Lafay ◽  
Erika Bullier ◽  
Jeremy J. Burdon

Rhizobial bacteria almost exclusively nodulate members of the families Fabaceae, Mimosaceae and Caesalpiniaceae, but are found on a single non-legume taxon, Parasponia (Ulmaceae). Based on their host-range, their nitrogen-fixing ability and strain competition experiments, bacterial strains isolated from Parasponia were thought to constitute a separate lineage that would account for their exceptional host affinity. This hypothesis was investigated by focusing on four isolates that are representative of the morphological and cultural types of Parasponia-nodulating bradyrhizobia. Their evolutionary relationships with other rhizobia were analysed using 16S rRNA gene sequences and their nodulation properties were explored using the nodA gene as a proxy for host-range specificity. Phylogenetic analyses of the 16S rRNA and nodA gene sequences revealed that bacterial isolates from Parasponia species are embedded among other bradyrhizobia. They did not cluster together in topologies based on the 16S rRNA or nodA gene sequences, but were scattered among other bradyrhizobia belonging to either the Bradyrhizobium japonicum or the Bradyrhizobium elkanii lineages. These data suggest that the ability of some bradyrhizobia to nodulate species of the genus Parasponia does not represent a historical relationship that predates the relationship between rhizobia and legumes, but is probably a more recent host switch for some rhizobia.


2007 ◽  
Vol 57 (6) ◽  
pp. 1217-1221 ◽  
Author(s):  
Jung-Hoon Yoon ◽  
So-Jung Kang ◽  
Sooyeon Park ◽  
Tae-Kwang Oh

Two Gram-negative, non-spore-forming, motile and helical-shaped bacterial strains, K92T and K93, were isolated from sludge from a dye works in Korea, and their taxonomic positions were investigated by means of a polyphasic approach. Strains K92T and K93 grew optimally at 37 °C and pH 7.0–8.0 in the presence of 0.5 % (w/v) NaCl. They contained Q-10 as the predominant ubiquinone and C18 : 1 ω7c as the major fatty acid. The major polar lipids were phosphatidylcholine, phosphatidylglycerol, diphosphatidylglycerol, phosphatidylethanolamine and two unidentified amino-group-containing lipids that were ninhydrin-positive. Their DNA G+C contents were 70.0 mol%. The 16S rRNA gene sequences of K92T and K93 showed no differences, and the two strains had a mean DNA–DNA relatedness of 93 %. Phylogenetic analyses based on 16S rRNA gene sequences showed that strains K92T and K93 formed a distinct evolutionary lineage within the Alphaproteobacteria. The 16S rRNA gene sequences of strains K92T and K93 exhibited similarity values of less than 91.5 % with respect to the 16S rRNA gene sequences of other members of the Alphaproteobacteria. The two strains were distinguishable from phylogenetically related genera through differences in several phenotypic properties. On the basis of the phenotypic, phylogenetic and genetic data, strains K92T and K93 represent a novel genus and species, for which the name Caenispirillum bisanense gen. nov., sp. nov. is proposed. The type strain of Caenispirillum bisanense is K92T (=KCTC 12839T=JCM 14346T).


2005 ◽  
Vol 55 (5) ◽  
pp. 2051-2055 ◽  
Author(s):  
Jung-Hoon Yoon ◽  
So-Jung Kang ◽  
Soo-Young Lee ◽  
Choong-Hwan Lee ◽  
Tae-Kwang Oh

Two Gram-negative, non-spore-forming, slightly halophilic gliding bacterial strains, DSW-8T and DSW-9, were isolated from sea water off a Korean island, Dokdo, of the East Sea, Korea, and their taxonomic position was investigated by a polyphasic study. The two strains grew optimally at 30 °C and in the presence of 2–3 % (w/v) NaCl. Strains DSW-8T and DSW-9 were characterized chemotaxonomically as containing MK-6 as the predominant menaquinone and iso-C17 : 0 3-OH, iso-C15 : 0 and iso-C15 : 1 as the major fatty acids. Major polar lipids were phosphatidylethanolamine, two unidentified phospholipids, an unidentified glycolipid and an amino group-containing lipid that was ninhydrin-positive. Their DNA G+C contents were 36·1 and 35·9 mol%. Phylogenetic analyses based on 16S rRNA gene sequences showed that strains DSW-8T and DSW-9 fell within the genus Maribacter of the family Flavobacteriaceae. Strains DSW-8T and DSW-9 exhibited no difference in their 16S rRNA gene sequences and possessed a mean DNA–DNA relatedness level of 89 %. Strains DSW-8T and DSW-9 exhibited 16S rRNA gene sequence similarity levels of 96·9–98·0 % to the type strains of the four recognized Maribacter species, but their low level of DNA–DNA relatedness with these species demonstrated that they constitute a distinct Maribacter species. On the basis of phenotypic and phylogenetic data and genetic distinctiveness, strains DSW-8T (=KCTC 12393T=DSM 17201T) and DSW-9 were classified in the genus Maribacter as members of a novel species, for which the name Maribacter dokdonensis sp. nov. is proposed.


2007 ◽  
Vol 57 (7) ◽  
pp. 1386-1390 ◽  
Author(s):  
Jung-Hoon Yoon ◽  
Soon Ei Park ◽  
So-Jung Kang ◽  
Tae-Kwang Oh

Two Gram-negative, motile, non-spore-forming bacterial strains, SW-353T and SW-369, were isolated from seawater from the East Sea, Korea, and their taxonomic positions were investigated by means of a polyphasic study. Strains SW-353T and SW-369 grew optimally at 30–37 °C and pH 7.0–8.0. Strains SW-353T and SW-369 contained Q-8 as the predominant ubiquinone and contained C16 : 0, C18 : 1 ω7c and C16 : 1 ω7c and/or iso-C15 : 0 2-OH as the major fatty acids. The DNA G+C contents were 50.1 and 50.5 mol%. Strains SW-353T and SW-369 exhibited no differences in their 16S rRNA gene sequences and showed a mean DNA–DNA relatedness level of 91 %. Phylogenetic analyses based on 16S rRNA gene sequences showed that strains SW-353T and SW-369 belong to the genus Rheinheimera. Similarity values between the 16S rRNA gene sequences of the two isolates and the type strains of the recognized Rheinheimera species were in the range 96.6–97.9 %. DNA–DNA relatedness data and differential phenotypic properties, together with the phylogenetic distinctiveness, demonstrated that strains SW-353T and SW-369 differ from the recognized Rheinheimera species. On the basis of phenotypic, phylogenetic and genetic data, therefore, strains SW-353T and SW-369 represent a novel species of the genus Rheinheimera, for which the name Rheinheimera aquimaris sp. nov. is proposed. The type strain is SW-353T (=KCTC 12840T=JCM 14331T).


Author(s):  
Shan Jiang ◽  
Feng-Bai Lian ◽  
You-Yang Sun ◽  
Xiao-Kui Zhang ◽  
Zong-Jun Du

A Gram-stain-negative, rod-shaped and facultatively aerobic bacterial strain, designated F7430T, was isolated from coastal sediment collected at Jingzi Wharf in Weihai, PR China. Cells of strain F7430T were 0.3–0.4 µm wide, 2.0–2.6 µm long, non-flagellated, non-motile and formed pale-beige colonies. Growth was observed at 4–40 °C (optimum, 30 °C), pH 6.0–9.0 (optimum, pH 7.5–8.0) and at NaCl concentrations of 1.0–10.0 % (w/v; optimum, 1.0 %). The sole respiratory quinone of strain F7430T was ubiquinone 8 and the predominant cellular fatty acids were summed feature 8 (C18 : 1  ω7c / C18 : 1  ω6c; 60.7 %), summed feature 3 (C16 : 1  ω7c/C16 : 1  ω6c; 30.2 %) and C15 : 0 iso (13.9 %). The polar lipids of strain F7430T consisted of diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, phosphatidylcholine, one unidentified phospholipid and three unidentified lipids. Results of 16S rRNA gene sequences analyses indicated that this strain belonged to the family Halieaceae and had high sequence similarities to Parahaliea aestuarii JCM 51547T (95.3 %) and Halioglobus pacificus DSM 27932T (95.2 %) followed by 92.9–95.0 % sequence similarities to other type species within the aforementioned family. The rpoB gene sequences analyses indicated that the novel strain had the highest sequence similarities to Parahaliea aestuarii JCM 51547T (82.2 %) and Parahaliea mediterranea DSM 21924T (82.2 %) followed by 75.2–80.5 % sequence similarities to other type species within this family. Phylogenetic analyses showed that strain F7430T constituted a monophyletic branch clearly separated from the other genera of family Halieaceae . Whole-genome sequencing of strain F7430T revealed a 3.3 Mbp genome size with a DNA G+C content of 52.6 mol%. The genome encoded diverse metabolic pathways including the Entner–Doudoroff pathway, assimilatory sulphate reduction and biosynthesis of dTDP-l-rhamnose. Based on results from the current polyphasic study, strain F7430T is proposed to represent a novel species of a new genus within the family Halieaceae , for which the name Sediminihaliea albiluteola gen. nov., sp. nov. is proposed. The type strain of the type species is F7430T (=KCTC 72873T=MCCC 1H00420T).


Author(s):  
Caixin Yang ◽  
Yibo Bai ◽  
Kui Dong ◽  
Jing Yang ◽  
Xin-He Lai ◽  
...  

Four Gram-stain-positive, catalase-negative, non-spore-forming, rod-shaped bacterial strains (zg-325T, zg329, dk561T and dk752) were isolated from the respiratory tract of marmot (Marmota himalayana) and the faeces of Tibetan gazelle (Procapra picticaudata) from the Qinghai-Tibet Plateau of PR China. The results of 16S rRNA gene sequence-based phylogenetic analyses indicated that strains zg-325T and dk561T represent members of the genus Actinomyces , most similar to Actinomyces denticolens DSM 20671T and Actinomyces ruminicola B71T, respectively. The DNA G+C contents of strains zg-325T and dk561T were 71.6 and 69.3 mol%, respectively. The digital DNA–DNA hybridization values of strains zg-325T and dk561T with their most closely related species were below the 70 % threshold for species demarcation. The four strains grew best at 35 °C in air containing 5 % CO2 on brain heart infusion (BHI) agar with 5 % sheep blood. All four strains had C18:1ω9c and C16:0 as the major cellular fatty acids. MK-8 and MK-9 were the major menaquinones in zg-325T while MK-10 was predominant in dk561T. The major polar lipids included diphosphatidylglycerol and phosphatidylinositol. On the basis of several lines of evidence from phenotypic and phylogenetic analyses, zg-325T and dk561T represent novel species of the genus Actinomyces , for which the name Actinomyces marmotae sp. nov. and Actinomyces procaprae sp. nov. are proposed. The type strains are zg-325T (=GDMCC 1.1724T=JCM 34091T) and dk561T (=CGMCC 4.7566T=JCM 33484T). We also propose, on the basis of the phylogenetic results herein, the reclassification of Actinomyces liubingyangii and Actinomyces tangfeifanii as Boudabousia liubingyangii comb. nov. and Boudabousia tangfeifanii comb. nov., respectively.


Author(s):  
Hiroyuki Sawada ◽  
Takashi Fujikawa ◽  
Shigeru Osada ◽  
Mamoru Satou

Five phytopathogenic bacterial strains, MAFF 301449T, MAFF 301450, MAFF 301451, MAFF 301452, and MAFF 301453, which were isolated from bud blight lesions of cyclamen (Cyclamen persicum Mill.) in Miyagi, Japan, were subjected to polyphasic taxonomic characterisation. The cells were Gram-reaction-negative, aerobic, non-spore-forming, motile with one to five polar flagella, and rod-shaped. Analysis of 16S rRNA gene sequences showed that they belong to the genus Pseudomonas , with Pseudomonas extremaustralis 14-3T (99.79 % sequence similarity), Pseudomonas trivialis DSM 14937T (99.79 %), Pseudomonas poae DSM 14936T (99.72 %), and Pseudomonas antarctica CMS 35T (99.72 %) as their relatives. The genomic DNA G+C content was 60.3 mol% and the major fatty acids (>5 % of the total fatty acids) were C16 : 0, summed feature 3 (C16 : 1 ω7c/C16 : 1 ω6c), summed feature 8 (C18 : 1 ω7c/C18 : 1 ω6c), and C17 : 0 cyclo. Phylogenetic analysis using the rpoD gene sequences and phylogenomic analyses based on the whole genome sequences demonstrated that the strains are members of the Pseudomonas fluorescens subgroup, but form a monophyletic and robust clade separated from their relatives. Average nucleotide identity and digital DNA–DNA hybridisation analyses with the closely related Pseudomonas species corroborated their novel species status. The strains were differentiated from their relatives by phenotypic characteristics, pathogenicity towards cyclamen, cellular fatty acid composition, and whole-cell MALDI-TOF mass spectrometry profiles. Based on the phenotypic, chemotaxonomic, and genotypic data obtained, we conclude that the strains represent a novel Pseudomonas species, for which we propose the name Pseudomonas cyclaminis sp. nov.; the type strain is MAFF 301449T (=ICMP 23720T).


Nematology ◽  
2017 ◽  
Vol 19 (3) ◽  
pp. 333-350 ◽  
Author(s):  
Shigeyuki Sekimoto ◽  
Taketo Uehara ◽  
Takayuki Mizukubo

The Korean cyst nematode, Heterodera koreana, was recorded for the first time from Japan and characterised morphologically, morphometrically and molecularly. In total, 41 populations were detected from soil samples collected from the rhizosphere of four bamboo species in Japan: 31 populations from moso bamboo (Phyllostachys edulis), seven from madake (P. bambusoides), two from henon bamboo (P. nigra var. henonis) and one from fish pole bamboo (P. aurea). The morphology and morphometrics of the Japanese population were in agreement with those of the original description of H. koreana from South Korea and other subsequent descriptions from China and Iran, with the exception of some minor differences. The results of the phylogenetic analyses of the D2-D3 expansion segments of 28S rRNA gene and ITS rRNA gene sequences confirmed the species identification and phylogenetic relationship of H. koreana with other Heterodera species. The COI mtDNA gene sequences were obtained for the first time for H. koreana. Three COI haplotypes found in Japanese H. koreana populations showed a characteristic geographical distribution in Japan.


2011 ◽  
Vol 61 (5) ◽  
pp. 1182-1188 ◽  
Author(s):  
Ki-Hoon Oh ◽  
Yong-Taek Jung ◽  
Tae-Kwang Oh ◽  
Jung-Hoon Yoon

A Gram-negative-staining, non-motile and rod-shaped bacterial strain, HD-28T, was isolated from a tidal flat of the Yellow Sea, Korea. Strain HD-28T grew optimally at pH 7.0–8.0 and 30 °C in the presence of 2–3 % (w/v) NaCl. Phylogenetic analyses based on 16S rRNA gene sequences showed that strain HD-28T was most closely related to species of the genus Ruegeria and exhibited 95.5–96.9 % 16S rRNA gene sequence similarity to the type strains of Ruegeria species. A neighbour-joining phylogenetic tree based on gyrB gene sequences also showed that strain HD-28T fell within the cluster comprising recognized species of the genus Ruegeria, showing 77.5–83.9 % sequence similarity. Strain HD-28T contained Q-10 as the predominant ubiquinone and C18 : 1ω7c as the major fatty acid. The major polar lipids detected in strain HD-28T were phosphatidylcholine, phosphatidylglycerol, an unidentified aminolipid and two unidentified lipids. The DNA G+C content was 57.9 mol%. Differential phenotypic properties, together with phylogenetic distinctiveness, demonstrated that strain HD-28T could be distinguished from recognized species of the genus Ruegeria. On the basis of phenotypic, chemotaxonomic and phylogenetic data, strain HD-28T is considered to represent a novel species of the genus Ruegeria, for which the name Ruegeria faecimaris sp. nov. is proposed. The type strain is HD-28T ( = KCTC 23044T = CCUG 58878T).


2007 ◽  
Vol 57 (9) ◽  
pp. 2089-2095 ◽  
Author(s):  
Jung-Hoon Yoon ◽  
So-Jung Kang ◽  
Sooyeon Park ◽  
Tae-Kwang Oh

Two Gram-negative, non-motile, pleomorphic bacterial strains, DS-40T and DS-45T, were isolated from a soil sample collected from Dokdo, Korea, and their exact taxonomic positions were investigated by using a polyphasic approach. Strains DS-40T and DS-45T grew optimally at 25 °C and pH 6.5–7.5 in the presence of 0–1.0 % (w/v) NaCl. They contained MK-7 as the predominant menaquinone and possessed iso-C15 : 0, iso-C17 : 0 3-OH and summed feature 3 (C16 : 1 ω7c and/or iso-C15 : 0 2-OH) as the major fatty acids. The DNA G+C contents of strains DS-40T and DS-45T were 36.0 and 36.8 mol%, respectively. Strains DS-40T and DS-45T shared a 16S rRNA gene sequence similarity of 96.7 % and demonstrated a mean DNA–DNA relatedness level of 12 %. Phylogenetic analyses based on 16S rRNA gene sequences revealed that strains DS-40T and DS-45T were most closely phylogenetically affiliated with the genus Pedobacter of the family Sphingobacteriaceae. Strains DS-40T and DS-45T exhibited 16S rRNA gene sequence similarity values of 91.4–93.7 and 89.9–91.6 % with respect to the type strains of Pedobacter and Sphingobacterium species, respectively. Phenotypic and chemotaxonomic properties, together with the phylogenetic data, support the assignment of strains DS-40T and DS-45T as two distinct species within the genus Pedobacter. On the basis of phenotypic, phylogenetic and genetic data, strains DS-40T and DS-45T represent two novel species of the genus Pedobacter, for which the names Pedobacter lentus sp. nov. and Pedobacter terricola sp. nov. are proposed, respectively. The respective type strains are DS-40T (=KCTC 12875T=JCM 14593T) and DS-45T (=KCTC 12876T=JCM 14594T).


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