Cryptic plasmid pSKU146 from the wall-less plant pathogen Spiroplasma kunkelii encodes an adhesin and components of a type IV translocation-related conjugation system

Davis, Robert E.; Dally, E. L.; Jomantienė, R.; Zhao, Yan; Roe, Bruce A.; Lin, Shaoping; Shao, Jonathan

doi:10.1016/j.plasmid.2004.09.002

Cited by 33 publications

(37 citation statements)

References 39 publications

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“…S4). Clustering of Soj from S. citri pSciA and pSci6 and S. kunkelii pSKU146 with those of the mycoplasmal mobile elements is consistent with previous observations that the arrangement of three CDS of pSKU146 paralleled that of their counterparts in the integrated conjugative element (ICE) of Mycoplasma fermentans (Calcutt et al, 2002;Davis et al, 2005), and suggests that spiroplasma plasmids and mycoplasma ICEs might have a common ancestor. It is noteworthy that, in contrast to spiroplasmas, most mycoplasmas do not possess parA/soj genes (Livny et al, 2007), and that mycoplasmas having parA/soj-like sequences all belong to the 'pneumoniae' phylogenetic group.…”

Section: Partitioning Protein Sojsupporting

confidence: 89%

“…In particular, they do not share any homology with the phytoplasma plasmids that encode putative replication proteins (Rep) having the conserved motifs associated with the rolling circle mechanism of replication (Oshima et al, 2001;Tran-Nguyen & Gibb, 2006). S. citri plasmids pSciA and pSci1-6 all possess genes soj and pE, which are also conserved in plasmids pBJS-O from S. citri BR3 (Joshi et al, 2005) and pSKU146 from S. kunkelii CR2-3X (Davis et al, 2005). In this study, we showed that pE is essential and the only plasmid-encoded protein required for plasmid replication.…”

Section: Discussion Replication Protein Pementioning

confidence: 99%

“…3). The largest group consisted of PEs from pSci1-5 and the PE counterparts of pBJS-O from S. citri BR3 (Joshi et al, 2005) and pSKU146 from S. kunkelii CR2-3X (Davis et al, 2005). Unexpectedly, whereas one PE (PE2) from pSci6 also fell in this group, the Fig.…”

mentioning

confidence: 89%

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Characterizing the replication and stability regions of Spiroplasma citri plasmids identifies a novel replication protein and expands the genetic toolbox for plant-pathogenic spiroplasmas

et al. 2008

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Spiroplasma citri strain GII3 contains seven plasmids, pSciA and pSci1-6, that share extensive regions of sequence homology and display a mosaic gene organization. Plasmid pSci2 comprises 12 coding sequences (CDS), three of which encode polypeptides homologous to proteins Soj/ ParA, involved in chromosome partitioning, and TrsE and Mob/TraG, implicated in the type IV secretion pathway. One CDS encodes the adhesin-like protein ScARP3d whereas the other eight encode polypeptides with no homology to known proteins. The pSci2 CDS pE and soj have counterparts in all seven plasmids. Through successive deletions, various pSci2 derivatives were constructed and assessed for their ability to replicate by transformation of S. citri 44, a strain which has no plasmid. The smallest functional replicon was found to contain a single CDS (pE) and its flanking intergenic regions. Shuttle (S. citri/Escherichia coli) plasmids, in which CDS pE was disrupted, failed to replicate in S. citri, suggesting that PE is the replication protein of the S. citri plasmids. Successive propagations of pSci2-derived transformed spiroplasmas, in the absence of selection pressure, revealed that only pSci2 derivatives having an intact soj gene were stably maintained, indicating that the soj-encoded polypeptide is most likely involved in plasmid partitioning. Upon transformation, pSci2 derivatives, including shuttle (S. citri/E. coli) plasmids, were shown to replicate in all S. citri strains tested regardless of whether the strain possesses endogenous plasmids, such as strain GII3, or not, such as strain R8A2. In addition, the pSci replicons were introduced efficiently into the plant-pathogenic spiroplasmas Spiroplasma kunkelii and Spiroplasma phoeniceum, the transformation of which had never, to our knowledge, been described before. These studies show that, besides their implications for the biology of S. citri, the pSci plasmids hold considerable promise as vectors of general use for genetic studies of plantpathogenic spiroplasmas. As an example, a HA-tagged S. citri protein was expressed in S. kunkelii. Detection of pE-hybridizing sequences in various group I spiroplasma species indicated that pE replicating plasmids were not restricted to the three plant-pathogenic spiroplasmas. INTRODUCTIONSpiroplasmas are a group of helical, cell-wall-free bacteria belonging to the class Mollicutes. Three spiroplasma species, Spiroplasma citri (Saglio et al., 1973), Spiroplasma kunkelii (Whitcomb et al., 1986) and Spiroplasma phoeniceum (Saillard et al., 1987), have been associated with plant diseases. S. citri is the aetiological agent of the citrus stubborn and horseradish brittle root diseases and was the first plant mollicute to be cultured in vitro (Fletcher et al., 1981;Saglio et al., 1971). Since then, S. citri has been studied extensively (Bové et al., 1989(Bové et al., , 2003. The availability of both an experimental transmission assay via the leafhopper vector (Foissac et al., 1996) and gene transfer systems (Foissac et al., 1997;Renaudin, 2002;Renaudi...

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Section: Partitioning Protein Sojsupporting

confidence: 89%

Section: Discussion Replication Protein Pementioning

confidence: 99%

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Characterizing the replication and stability regions of Spiroplasma citri plasmids identifies a novel replication protein and expands the genetic toolbox for plant-pathogenic spiroplasmas

et al. 2008

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“…73,2009 BIOLOGICAL DIVERSITY OF PROKARYOTIC T4SS 777 processing of conjugative DNA elements, yet most of them still rely on a T4CP to recruit and bind protein substrates. Some T4SS of medical importance, e.g., the Bordetella pertussis Ptl and Brucella sp.…”

Section: Effector Translocator Systemsmentioning

confidence: 99%

“…The outcome of these investigations led to a general model that secretion signals are positioned near the C VOL. 73,2009 BIOLOGICAL DIVERSITY OF PROKARYOTIC T4SS 779 termini and consist of clusters of hydrophobic or positively charged residues. More recent findings, however, suggest that substrate recognition is mediated by a combination of C-terminal signals, additional intrinsic motifs, and other cellular factors, e.g., chaperones and accessory proteins (Table 1).…”

Section: Substrate Recognition Signals Secretion Chaperones and Accmentioning

confidence: 99%

Biological Diversity of Prokaryotic Type IV Secretion Systems

Martı́nez

Christie

2009

Microbiol Mol Biol Rev

623

780

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SUMMARY Type IV secretion systems (T4SS) translocate DNA and protein substrates across prokaryotic cell envelopes generally by a mechanism requiring direct contact with a target cell. Three types of T4SS have been described: (i) conjugation systems, operationally defined as machines that translocate DNA substrates intercellularly by a contact-dependent process; (ii) effector translocator systems, functioning to deliver proteins or other macromolecules to eukaryotic target cells; and (iii) DNA release/uptake systems, which translocate DNA to or from the extracellular milieu. Studies of a few paradigmatic systems, notably the conjugation systems of plasmids F, R388, RP4, and pKM101 and the Agrobacterium tumefaciens VirB/VirD4 system, have supplied important insights into the structure, function, and mechanism of action of type IV secretion machines. Information on these systems is updated, with emphasis on recent exciting structural advances. An underappreciated feature of T4SS, most notably of the conjugation subfamily, is that they are widely distributed among many species of gram-negative and -positive bacteria, wall-less bacteria, and the Archaea. Conjugation-mediated lateral gene transfer has shaped the genomes of most if not all prokaryotes over evolutionary time and also contributed in the short term to the dissemination of antibiotic resistance and other virulence traits among medically important pathogens. How have these machines adapted to function across envelopes of distantly related microorganisms? A survey of T4SS functioning in phylogenetically diverse species highlights the biological complexity of these translocation systems and identifies common mechanistic themes as well as novel adaptations for specialized purposes relating to the modulation of the donor-target cell interaction.

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Spiroplasma

Williamson¹,

Gasparich²,

Regassa³

et al. 2015

Bergey's Manual of Systematics of Archaea and Bacteria

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Spi.ro.plas'ma. Gr. n. speira (L. transliteration spira ) a coil, spiral; Gr. neut. n. plasma something formed or molded, a form; N.L. neut. n. Spiroplasma spiral form. Tenericutes / Mollicutes / Entomoplasmatales / Spiroplasmataceae / Spiroplasma Cells are pleomorphic, varying in size and shape from helical and branched nonhelical filaments to spherical or ovoid. The helical forms, usually 100–200 nm in diameter and 3–5 µm in length, generally occur during the exponential phase of growth and in some species persist during stationary phase. The cells of some species are short (1–2 µm). In certain cases, helical cells may be very tightly coiled, or the coils may show continuous variation in amplitude. Spherical cells ~300 nm in diameter and nonhelical filaments are frequently seen in the stationary phase, where they may not be viable, and in all growth phases in suboptimal growth media, where they may or may not be viable. In some species during certain phases, spherical forms may be the replicating form. Helical filaments are motile, with flexional and twitching movements, and often show an apparent rotatory motility. Fibrils are associated with the membrane, but flagellae, periplasmic fibrils, or other organelles of locomotion are absent . Fimbriae and pili observed on the cell surface of insect‐ and plant‐pathogenic spiroplasmas are believed to be involved in host‐cell attachment and conjugation (Ammar et al., 2004; Özbek et al., 2003), but not in locomotion. Cells divide by binary fission, with doubling times of 0.7–37 h. Facultatively anaerobic. The temperature growth range varies among species, from 5 to 41°C. Colonies on solid media are frequently diffuse , with irregular shapes and borders, a condition that reflects the motility of the cells during active growth (Figure 111). Colony type is strongly dependent on the agar concentration. Colony sizes vary from 0.1 to 4.0 mm in diameter. Colonies formed by nonmotile variants or mutants, or by cultures growing on inadequate media are typically umbonate with diameters of 200 µm or less. Some species, such as Spiroplasma platyhelix , have barely visible helicity along most of their length and display little rotatory or flexing motility. Colonies of motile, fast‐growing spiroplasmas are diffuse, often with satellite colonies developing from foci adjacent to the initial site of colony development. Light turbidity may be produced in liquid cultures. Chemo‐organotrophic. Acid is produced from glucose. Hydrolysis of arginine is variable. Urea, arbutin, and esculin are not hydrolyzed. Sterol requirements are variable. An optimum osmolality, usually in the range of 300–800 mOsm, has been demonstrated for some spiroplasmas. Media containing mycoplasma broth base, serum, and other supplements are required for primary growth, but after adaptation, growth often occurs in less complex media. Defined or semi‐defined media are available for some species. Resistant to 10,000 U/ml penicillin. Insensitive to rifampicin, sensitive to erythromycin and tetracycline. Isolated from the surfaces of flowers and other plant parts, from the guts and hemolymph of various insects and crustaceans, and from tick triturates. Also isolated from vascular plant fluids ( phloem sap ) and insects that feed on the fluids . Specific host associations are common. The type species, Spiroplasma citri , is pathogenic for citrus (e.g., orange and grapefruit), producing “stubborn” disease. Experimental or natural infections also occur in horseradish, periwinkle, radish, broad bean, carrot, and other plant species. Spiroplasma kunkelii is a maize pathogen. Some species are pathogenic for insects. Certain species are pathogenic, under experimental conditions, for a variety of suckling rodents (rats, mice, hamsters and rabbits) and/or chicken embryos. Genome sizes vary from 780 to 2220 kbp (PFGE). DNA G + C content ( mol %): 24–31 ( T m , Bd). Type species : Spiroplasma citri Saglio, L'Hospital, Laflèche, Dupont, Bové, Tully and Freundt 1973, 202 AL .

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Cryptic plasmid pSKU146 from the wall-less plant pathogen Spiroplasma kunkelii encodes an adhesin and components of a type IV translocation-related conjugation system

Cited by 33 publications

References 39 publications

Characterizing the replication and stability regions of Spiroplasma citri plasmids identifies a novel replication protein and expands the genetic toolbox for plant-pathogenic spiroplasmas

Characterizing the replication and stability regions of Spiroplasma citri plasmids identifies a novel replication protein and expands the genetic toolbox for plant-pathogenic spiroplasmas

Biological Diversity of Prokaryotic Type IV Secretion Systems

Spiroplasma

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