Evidence that the exoH gene of Sinorhizobium meliloti does not appear to influence symbiotic effectiveness with Medicago truncatula ‘Jemalong A17’

2010 ◽  
Vol 56 (12) ◽  
pp. 996-1002 ◽  
Author(s):  
Kais Zribi ◽  
Haythem Mhadhbi ◽  
Yazid Badri ◽  
Mohamed Elarbi Aouani ◽  
Peter van Berkum

The purpose of this study was to identify strains of Sinorhizobium meliloti that formed either an effective or completely ineffective symbiosis with Medicago truncatula L. ‘Jemalong A17’ and, subsequently, to determine whether differences existed between their exoH genes. Sinorhizobium meliloti TII7 and A5 formed an effective and ineffective symbiosis with M. truncatula ‘Jemalong A17’, respectively. Using a multilocus sequence typing method, both strains were shown to have chromosomes identical with S. meliloti Rm1021 and RCR2011. The 2260-bp segments of DNA stretching from the 3′ end of exoI through open reading frames of hypothetical proteins SM_b20952 and SM_b20953 through exoH into the 5′ end of exoK in strains TII7 and Rm1021 differed by a single nucleotide at base 127 of the hypothetical protein SM_b20953. However, the derived amino acid sequences of the exoH genes of effective TII7, ineffective A5, and strain Rm1021 were shown to be identical with each other. Therefore, it would seem unlikely that the gene product of exoH is directly involved with the low efficiency of a symbiosis of strain Rm1021 with M. truncatula ‘Jemalong A17’. Complementation or complete genome sequence analyses involving strains TII7 and A5 might be useful approaches to investigate the molecular bases for the differential symbiotic response with M. truncatula ‘Jemalong A17’.

2009 ◽  
Vol 2009 ◽  
pp. 1-10 ◽  
Author(s):  
Daniela Lepka ◽  
Tobias Kerrinnes ◽  
Evelyn Skiebe ◽  
Birgitt Hahn ◽  
Angelika Fruth ◽  
...  

We report the nucleotide sequence of two novel cryptic plasmids (4357 and 14 662 base pairs) carried by aYersinia enterocoliticabiotype 1A strain isolated from pork. As distinguished from most biotype 1A strains, this isolate, designated 07-04449, exhibited adherence to eukaryotic cells. The smaller plasmid pYe4449-1 carries five attributable open reading frames (ORFs) encoding the first CcdA/CcdB-like antitoxin/toxin system described for aYersiniaplasmid, a RepA-like replication initiation protein, and mobilizing factors MobA and MobC. The deduced amino acid sequences showed highest similarity to proteins described inSalmonella(CcdA/B),Klebsiella(RepA), andPlesiomonas(MobA/C) indicating genomic fluidity among members of theEnterobacteriaceae. One additional ORF with unknown function, termed ORF5, was identified with an ancestry distinct from the rest of the plasmid. While the C+G content of ORF5 is 38.3%, the rest of pYe4449-1 shows a C+G content of 55.7%. The C+G content of the larger plasmid pYe4449-2 (54.9%) was similar to that of pYe4449-1 (53.7%) and differed from that of theY. enterocoliticagenome (47.3%). Of the 14 ORFs identified on pYe4449-2, only six ORFs showed significant similarity to database entries. For three of these ORFs likely functions could be ascribed: a TnpR-like resolvase and a phage replication protein, localized each on a low C+G island, and DNA primase TraC. Two ORFs of pYe4449-2, ORF3 and ORF7, seem to encode secretable proteins. Epitope-tagging of ORF3 revealed protein expression at4°Cbut not at or above27°Csuggesting adaptation to a habitat outside swine. The hypothetical protein encoded by ORF7 is the member of a novel repeat protein family sharing theDxxGN(x)nDxxGNmotif. Our findings illustrate the exceptional gene pool diversity within the speciesY. enterocoliticadriven by horizontal gene transfer events.


2002 ◽  
Vol 68 (3) ◽  
pp. 1220-1227 ◽  
Author(s):  
Masayuki Hashimoto ◽  
Mitsuru Fukui ◽  
Kouichi Hayano ◽  
Masahito Hayatsu

ABSTRACT Rhizobium sp. strain AC100, which is capable of degrading carbaryl (1-naphthyl-N-methylcarbamate), was isolated from soil treated with carbaryl. This bacterium hydrolyzed carbaryl to 1-naphthol and methylamine. Carbaryl hydrolase from the strain was purified to homogeneity, and its N-terminal sequence, molecular mass (82 kDa), and enzymatic properties were determined. The purified enzyme hydrolyzed 1-naphthyl acetate and 4-nitrophenyl acetate indicating that the enzyme is an esterase. We then cloned the carbaryl hydrolase gene (cehA) from the plasmid DNA of the strain and determined the nucleotide sequence of the 10-kb region containing cehA. No homologous sequences were found by a database homology search using the nucleotide and deduced amino acid sequences of the cehA gene. Six open reading frames including the cehA gene were found in the 10-kb region, and sequencing analysis shows that the cehA gene is flanked by two copies of insertion sequence-like sequence, suggesting that it makes part of a composite transposon.


1998 ◽  
Vol 71 (1) ◽  
pp. 11-19 ◽  
Author(s):  
YUJI YASUKOCHI ◽  
TOSHIO KANDA ◽  
TOSHIKI TAMURA

To clone the Bombyx xanthine dehydrogenase (XDH) gene as a dominant marker for silkworm transgenesis, we performed nested reverse transcriptase–polymerase chain reaction (RT-PCR) using embryonic mRNA and primers designed from the conserved region of Drosophila and rat XDH genes. Sequencing of amplified 180 bp fragments showed that two different sequences were present in the fragments. Since both possessed striking similarity to XDH genes of other organisms, we considered these to be portions of silkworm XDH genes and designated them BmXDH1 and BmXDH2. Subsequently we cloned separately the entire region of the two cDNAs by PCR using phage DNA of an embryonic cDNA library and sequenced them. The two cDNAs were around 4 kb in size and possessed complete open reading frames. The deduced amino acid sequences of the two BmXDHs were very similar to each other and to those of other organisms. The expression pattern of wild-type larvae basically followed the tissue specificity of the enzyme and no significant difference was observed between the two XDH genes. The expression of both genes was detected in the XDH-deficient mutants, oq and og, but non-synonymous substitutions were specifically detected in the BmXDH1 of the oq mutant. In addition, a length polymorphism of the second intron of the BmXDH1 co-segregated with the oq translucent phenotype, suggesting that deficiency in BmXDH1 is the cause of the oq translucent phenotype.


2020 ◽  
Vol 47 (5) ◽  
pp. 425
Author(s):  
Mengyu Liu ◽  
Xiaofeng Liu ◽  
Junhua Hu ◽  
Yang Xue ◽  
Xiaochun Zhao

D-limonene is the main component of citrus essential oils. In the monoterpene biosynthetic pathway, geranyl diphosphate reacts with monoterpenes to form the prenyl-carbocation intermediate to produce d-limonene. In this study, d-limonene synthase (FcLS) genes were first isolated from Rongan kumquat (Fortunella crassifolia Swingle). Sequencing analysis revealed that the open reading frames of 18 FcLS genes contain 12 single nucleotide polymorphisms, which resulted in the variation of FcLS proteins, indicating that the limonene synthase genes are a large family in F. crassifolia. This phenomenon has not been reported in Citrus. The predicted FcLS proteins showed a high amino acid sequence identity with other Citrus limonene synthases and also had the typical structures of limonene synthase protein. FcLS1 was validated to be a functional d-limonene synthase by prokaryotic expression.


2004 ◽  
Vol 186 (14) ◽  
pp. 4730-4739 ◽  
Author(s):  
Andrea K. White ◽  
William W. Metcalf

ABSTRACT DNA sequencing and analysis of two distinct C—P lyase operons in Pseudomonas stutzeri WM88 were completed. The htxABCDEFGHIJKLMN operon encodes a hypophosphite-2-oxoglutarate dioxygenase (HtxA), whereas the predicted amino acid sequences of HtxB to HtxN are each homologous to the components of the Escherichia coli phn operon, which encodes C—P lyase, although homologs of E. coli phnF and phnO are absent. The genes in the htx operon are cotranscribed based on gene organization, and the presence of the intergenic sequences is verified by reverse transcription-PCR with total RNA. Deletion of the htx locus does not affect the ability of P. stutzeri to grow on phosphonates, indicating the presence of an additional C—P lyase pathway in this organism. To identify the genes comprising this pathway, a Δhtx strain was mutagenized and one mutant lacking the ability to grow on methylphosphonate as the sole P source was isolated. A ca.-10.6-kbp region surrounding the transposon insertion site of this mutant was sequenced, revealing 13 open reading frames, designated phnCDEFGHIJKLMNP, which were homologous to the E. coli phn genes. Deletion of both the htx and phn operons of P. stutzeri abolishes all growth on methylphosphonate and aminoethylphosphonate. Both operons individually support growth on methylphosphonate; however, the phn operon supports growth on aminoethylphosphonate and phosphite, as well. The substrate ranges of both C—P lyases are limited, as growth on other phosphonate compounds, including glyphosate and phenylphosphonate, was not observed.


2000 ◽  
Vol 182 (21) ◽  
pp. 6123-6129 ◽  
Author(s):  
Matthias Contzen ◽  
Andreas Stolz

ABSTRACT The genes for two different protocatechuate 3,4-dioxygenases (P34Os) were cloned from the 4-sulfocatechol-degrading bacteriumAgrobacterium radiobacter strain S2 (DSMZ 5681). ThepcaH1G1 genes encoded a P34O (P34O-I) which oxidized protocatechuate but not 4-sulfocatechol. These genes were part of a protocatechuate-degradative operon which strongly resembled the isofunctional operon from the protocatechuate-degrading strainAgrobacterium tumefaciens A348 described previously by D. Parke (FEMS Microbiol. Lett. 146:3–12, 1997). The second P34O (P34O-II), encoded by the pcaH2G2 genes, was functionally expressed and shown to convert protocatechuate and 4-sulfocatechol. A comparison of the deduced amino acid sequences of PcaH-I and PcaH-II, and of PcaG-I and PcaG-II, with each other and with the corresponding sequences from the P34Os, from other bacterial genera suggested that the genes for the P34O-II were obtained by strain S2 by lateral gene transfer. The genes encoding the P34O-II were found in a putative operon together with two genes which, according to sequence alignments, encoded transport proteins. Further downstream from this putative operon, two open reading frames which code for a putative regulator protein of the IclR family and a putative 3-carboxymuconate cycloisomerase were identified.


2003 ◽  
Vol 185 (22) ◽  
pp. 6658-6665 ◽  
Author(s):  
Kasumi Takeuchi ◽  
Fumiko Taguchi ◽  
Yoshishige Inagaki ◽  
Kazuhiro Toyoda ◽  
Tomonori Shiraishi ◽  
...  

ABSTRACT The deduced amino acid sequences of the flagellins of Pseudomonas syringae pv. tabaci and P. syringae pv. glycinea are identical; however, their abilities to induce a hypersensitive reaction are clearly different. The reason for the difference seems to depend on the posttranslational modification of the flagellins. To investigate the role of this posttranslational modification in the interactions between plants and bacterial pathogens, we isolated genes that are potentially involved in the posttranslational modification of flagellin in P. syringae pv. glycinea (glycosylation island); then defective mutants with mutations in these genes were generated. There are three open reading frames in the glycosylation island, designated orf1, orf2, and orf3. orf1 and orf2 encode putative glycosyltransferases, and mutants with defects in these open reading frames, Δorf1 and Δorf2, secreted nonglycosylated and slightly glycosylated flagellins, respectively. Inoculation tests performed with these mutants and original nonhost tobacco leaves revealed that Δorf1 and Δorf2 could grow on tobacco leaves and caused symptom-like changes. In contrast, these mutants failed to cause symptoms on original host soybean leaves. These data indicate that putative glycosyltransferases encoded in the flagellin glycosylation island are strongly involved in recognition by plants and could be the specific determinants of compatibility between phytopathogenic bacteria and plant species.


1999 ◽  
Vol 12 (7) ◽  
pp. 633-639 ◽  
Author(s):  
Changsik Oh ◽  
Sunggi Heu ◽  
Jae-Yong Yoo ◽  
Yongsup Cho

Transposon mutagenesis was used to isolate nonpathogenic mutants of Xanthomonas campestris pv. glycines 8ra, which causes bacterial pustule disease in soybean. A 6.1-kb DNA region in which a mutation gave loss of pathogenicity was isolated and found to carry six open reading frames (ORFs). Four ORFs had homology with hrcU, hrcV, hrcR, and hrcS genes of Ralstonia solanacearum and X. campestris pv. vesicatoria. One nonpathogenic mutant, X. campestris pv. glycines H80, lost pathogenicity on soybean but was able to elicit the hypersensitive response (HR) on nonhost pepper and tomato plants. This mutant still multiplied as well as the wild type in the leaves or cotyledons of soybean. Although the DNA and amino acid sequences showed high homology with known hrp genes, the hrcU-homolog ORF is not required for HR induction on nonhost plants, pepper and tomato, or for the multiplication of bacteria in the host plant. This gene was only required for the pathogenic symptoms of X. campestris pv. glycines 8ra on soybean.


Acta Naturae ◽  
2016 ◽  
Vol 8 (1) ◽  
pp. 117-125 ◽  
Author(s):  
V. A. Chernukhin ◽  
D. A. Gonchar ◽  
M. A. Abdurashitov ◽  
O. A. Belichenko ◽  
V. S. Dedkov ◽  
...  

Putative open reading frames of MD-endonucleases have been identified in Enterobacteria genomes as a result of the search for amino acid sequences homologous to MD-endonuclease BisI. A highly conserved DNA primary structure of these open reading frames in different genera of Enterobacteria (Escherichia, Klebsiella and Cronobacter) has allowed researchers to create primers for PCR screening, which was carried out on Enterobacteria DNA collected from natural sources. The DNA fragment, about 440 bp in length, was amplified by use of the genomic DNA of a wild E.coli LM N17 strain as a template and was inserted into the pMTL22 vector. Endonuclease activity was detected in an E.coli ER 2267 strain transformed with the obtained construction. A new enzyme named ElmI was purified by chromatographic techniques from the recombinant strain biomass. It was discovered that similarly to BisI this enzyme specifically cleaves the methylated DNA sequence 5-GCNGC- 3 before the central nucleotide N if this sequence contains two 5-methylcytosines. However, unlike BisI, ElmI more efficiently cleaves this sequence if more than two cytosine residues are methylated.


2015 ◽  
Author(s):  
Xiaoqiu Huang ◽  
Anindya Das ◽  
Binod B Sahu ◽  
Subodh K Srivastava ◽  
Leonor F Leandro ◽  
...  

Supernumerary chromosomes have been shown to transfer horizontally from one isolate to another. However, the mechanism by which horizontal chromosome transfer (HCT) occurs is unknown. In this study, we compared the genomes of 11 isolates comprising six Fusarium species that cause soybean sudden death syndrome (SDS) or bean root rot (BRR), and detected numerous instances of HCT in supernumerary chromosomes. We also identified a statistically significant number (21 standard deviations above the mean) of single nucleotide polymorphisms (SNPs) in the supernumerary chromosomes between isolates of the asexual pathogen F. virguliforme. Supernumerary chromosomes carried reverse transcriptase-related genes (RVT); the presence of long RVT open reading frames (ORFs) in the supernumerary chromosome was correlated with the presence of two or more chromosome copies with a significant number of SNPs between them. Our results suggest that supernumerary chromosomes transfer horizontally via an RNA intermediate. Understanding the mechanism by which HCT occurs will have a profound impact on understanding evolution and applying biotechnology as well as accepting HCT as a natural source of genetic variation.


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