<i>Spiroplasma citri</i> Movement into the Intestines and Salivary Glands of Its Leafhopper Vector, <i>Circulifer tenellus</i>

Kwon, Myoung-Ok; Wayadande, Astri; Fletcher, Jacqueline

doi:10.1094/phyto.1999.89.12.1144

Cited by 61 publications

(59 citation statements)

References 18 publications

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“…These phytopathogenic mollicutes are restricted to phloem and to certain vector tissues; thus, their vectors are phloem sap-feeding specialists. After being ingested from plant phloem by their insect vectors, they traverse the insect gut wall, move into the hemolymph, where they multiply, and invade the salivary glands (20,33,34,36). During their movements in the insect vector until its transmission to a new host plant, spiroplasmas and phytoplasmas must traverse two major physical barriers, namely, the insect intestine and the salivary gland (35,53).…”

mentioning

confidence: 99%

Entry of Spiroplasma citri into Circulifer haematoceps Cells Involves Interaction between Spiroplasma Phosphoglycerate Kinase and Leafhopper Actin

Labroussaa

Arricau‐Bouvery

Dubrana

et al. 2010

Appl Environ Microbiol

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Transmission of the phytopathogenic mollicutes, spiroplasmas, and phytoplasmas by their insect vectors mainly depends on their ability to pass through gut cells, to multiply in various tissues, and to traverse the salivary gland cells. The passage of these different barriers suggests molecular interactions between the plant mollicute and the insect vector that regulate transmission. In the present study, we focused on the interaction between Spiroplasma citri and its leafhopper vector, Circulifer haematoceps. An in vitro protein overlay assay identified five significant binding activities between S. citri proteins and insect host proteins from salivary glands. One insect protein involved in one binding activity was identified by liquid chromatography-tandem mass spectrometry (LC-MS/MS) as actin. Confocal microscopy observations of infected salivary glands revealed that spiroplasmas colocated with the host actin filaments. An S. citri actin-binding protein of 44 kDa was isolated by affinity chromatography and identified by LC-MS/MS as phosphoglycerate kinase (PGK). To investigate the role of the PGK-actin interaction, we performed competitive binding and internalization assays on leafhopper cultured cell lines (Ciha-1) in which His 6 -tagged PGK from S. citri or purified PGK from Saccharomyces cerevisiae was added prior to the addition of S. citri inoculum. The results suggested that exogenous PGK has no effect on spiroplasmal attachment to leafhopper cell surfaces but inhibits S. citri internalization, demonstrating that the process leading to internalization of S. citri in eukaryotic cells requires the presence of PGK. PGK, regardless of origin, reduced the entry of spiroplasmas into Ciha-1 cells in a dose-dependent manner.

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confidence: 99%

Entry of Spiroplasma citri into Circulifer haematoceps Cells Involves Interaction between Spiroplasma Phosphoglycerate Kinase and Leafhopper Actin

Labroussaa

Arricau‐Bouvery

Dubrana

et al. 2010

Appl Environ Microbiol

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“…Leafhopper heads, containing the salivary glands, were gently torn away from the thoraxes as described previously (22), rinsed in HEPES-sucrose buffer (8 mM HEPES [pH 7.4], 280 mM sucrose), and ground in groups of 5 in a Potter grinder with 1 ml of SP4 medium. After incubation (15 min at room temperature), the mixture was filtered through a 0.45-m-pore-size membrane for CFU determination.…”

Section: Methodsmentioning

confidence: 99%

“…In leafhoppers, spiroplasmas ingested from the phloem sieve tubes traverse the insect gut wall and move into the hemolymph, where they multiply and circulate. They eventually invade the salivary glands, where they multiply further (22,23). From there, they are introduced with saliva into the phloem of a new host plant.…”

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confidence: 99%

“…Spiroplasmas are then released into the salivary duct by exocytosis. Observation of membrane-bound cytoplasmic vesicles of midgut epithelium and salivary gland cells suggests that the spiroplasmas may cross these physical barriers by endocytosis involving a receptor-ligand interaction (22). At the present time, the molecular and cellular interactions contributing to the crossing of these physical barriers in the insect vector are poorly understood.…”

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confidence: 99%

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Disruption of a Gene Predicted To Encode a Solute Binding Protein of an ABC Transporter Reduces Transmission of Spiroplasma citri by the Leafhopper Circulifer haematoceps

Boutareaud

Danet

Garnier

et al. 2004

Appl Environ Microbiol

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Spiroplasma citri is transmitted from plant to plant by phloem-feeding leafhoppers. In an attempt to identify mechanisms involved in transmission, mutants of S. citri affected in their transmission must be available. For this purpose, transposon (Tn4001) mutagenesis was used to produce mutants which have been screened for their ability to be transmitted by the leafhopper vector Circulifer haematoceps to periwinkle plants. With one mutant (G76) which multiplied in leafhoppers as efficiently as S. citri wild-type (wt) strain GII-3, the plants showed symptoms 4 to 5 weeks later than those infected with wt GII-3. Thirty to fifty percent of plants exposed to leafhoppers injected with G76 remained symptomless, whereas for wt GII-3, all plants exposed to the transmission showed severe symptoms. This suggests that the mutant G76 was injected into plants by the leafhoppers less efficiently than wt GII-3. To check this possibility, the number of spiroplasma cells injected by a leafhopper through a Parafilm membrane into SP4 medium was determined. Thirty times less mutant G76 than wt GII-3 was transmitted through the membrane. These results suggest that mutant G76 was affected either in its capacity to penetrate the salivary glands and/or to multiply within them. In mutant G76, transposon Tn4001 was shown to be inserted into a gene encoding a putative lipoprotein (Sc76) In the ABCdb database Sc76 protein was noted as a solute binding protein of an ABC transporter of the family S1_b. Functional complementation of the G76 mutant with the Sc76 gene restored the wild phenotype, showing that Sc76 protein is involved in S. citri transmission by the leafhopper vector C. haematoceps.

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“…Additionally, it was shown that the Fd phytoplasma attaches specifically to the midgut and salivary glands of its insect vector in in situ assays (Lefol et al, 1993). Kwon et al (1999) showed that Spiroplasma citri probably enters Circulifer tenellus gut epithelium by a process of receptor-mediated cell endocytosis. These authors hypothesized that specific spiroplasma membrane proteins recognize receptors on leafhopper gut epithelial cells.…”

Section: Introductionmentioning

confidence: 99%

An immunodominant membrane protein gene from the Western X-disease phytoplasma is distinct from those of other phytoplasmas The GenBank accession number for the sequence reported in this work is AF225904.

et al. 2001

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Membrane proteins mediate several important processes, including attachment, in several Mollicute species. Phytoplasmas are non-culturable plant pathogenic mollicutes that are transmitted in a specific manner by certain phloem-feeding insect vectors. Because it is likely that phytoplasma membrane proteins are involved with some aspect of the transmission process, their identification, isolation and characterization are important first steps in understanding phytoplasma transmission. A 32 kDa immunodominant protein (IDP) from the Western X-disease (WX) phytoplasma was purified from infected plants by immunoprecipitation using monoclonal antibodies, and two peptides from a tryptic digest were sequenced. PCR primers designed from these sequences amplified a 145 bp product which hybridized with WX-related phytoplasmas in Southern blots. This PCR product was used to identify a 25 kbp EcoRI-HindIII fragment that was cloned and sequenced. A complete 864 bp ORF (idpA) was identified for which the putative translation product contained both of the tryptic digest peptide sequences that were used to design the PCR primers. Analysis of the predicted IdpA sequence indicated two transmembrane domains but no cleavage point. The amino acid sequence had no significant homology with other known phytoplasma IDP genes. The idpA ORF was cloned into an Escherichia coli expression vector and a fusion protein of the predicted size was identified in Western blots using a WX-specific antiserum. A rabbit polyclonal antiserum was prepared to the purified expression protein and this reacted with both the E. coli-expressed and native WX phytoplasma proteins. This newly identified WX IDP (IdpA) is distinct from other known mollicute membrane proteins.

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Spiroplasma citri Movement into the Intestines and Salivary Glands of Its Leafhopper Vector, Circulifer tenellus

Cited by 61 publications

References 18 publications

Entry of Spiroplasma citri into Circulifer haematoceps Cells Involves Interaction between Spiroplasma Phosphoglycerate Kinase and Leafhopper Actin

Entry of Spiroplasma citri into Circulifer haematoceps Cells Involves Interaction between Spiroplasma Phosphoglycerate Kinase and Leafhopper Actin

Disruption of a Gene Predicted To Encode a Solute Binding Protein of an ABC Transporter Reduces Transmission of Spiroplasma citri by the Leafhopper Circulifer haematoceps

An immunodominant membrane protein gene from the Western X-disease phytoplasma is distinct from those of other phytoplasmas The GenBank accession number for the sequence reported in this work is AF225904.

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