The infection of leafhoppers by western X-disease virus

Whitcomb, Robert F.; Jensen, D. D.; Richardson, Jean

doi:10.1016/0042-6822(66)90057-2

Cited by 29 publications

(1 citation statement)

References 21 publications

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“…They have also been visualized in vectors (15,16,25). Moreover, yellows agents in vitro have properties (22,38,40) similar to those of vertebrate Mycoplasma. Therefore, it would be a peculiar and unfortunate coincidence if the pleomorphic organisms in vectors and in phloem were not involved in disease production.…”

Section: Discussionmentioning

confidence: 99%

Evidence on Possible Mycoplasma Etiology of Aster Yellows Disease II. Suppression of Aster Yellows in Insect Vectors

Whitcomb

Davis

1970

Infect Immun

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Chlortetracycline or chloramphenicol (but not kanamycin, penicillin, or erythromycin), when administered in hydroponic solution to diseased aster, reduced the availability of the aster yellows (AY) agent to nymphs of Macrosteles fascifrons (Stal). Insects exposed to healthy plants whose roots were immersed in chlortetracycline were able to acquire AY agent from diseased plants the day after removal from the antibiotic-treated plants, but the latent period of the ensuing disease in the insects was prolonged. Chlortetracycline or tylosin tartrate blocked AY infection in nymphs injected with a mixture of antibiotic and the AY agent, but polymyxin, neomycin, vancomycin, penicillin, carbomycin, or chloramphenicol did not. All tetracyclines tested, methacycine, oxytetracycline, and chlortetracycline, produced a dramatic reduction in the ability of infected vectors to transmit AY agent. Tylosin tartrate also reduced transmission when injected into AY-transmitting vectors, but carbomycin, spectinomycin, cycloserine, penicillin, erythromycin, or kanamycin had no such effect. During the first 10 days after injection of tylosin tartrate or oxytetracycline into transmitting vectors, ability of the insects to transmit AY decayed rapidly. Transmission by insects injected with buffer alone, after decreasing the first day after injection, gradually returned to its normal level in less than 1 week. By 2 to 3 weeks after injection with tylosin or oxytetracycline, ability to transmit AY was regained by vectors. The results suggest that tetracycline antibiotics and tylosin tartrate inhibit multiplication of AY agent in the insect. The spectrum of antibiotic activity in the insect is consistent with the hypothesis that AY and other plant yellows diseases are caused by mycoplasma-like organisms.

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Section: Discussionmentioning

confidence: 99%

Evidence on Possible Mycoplasma Etiology of Aster Yellows Disease II. Suppression of Aster Yellows in Insect Vectors

Whitcomb

Davis

1970

Infect Immun

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CandidatusPhytoplasma

Harrison¹,

Gundersen‐Rindal²,

Davis³

et al. 2018

Bergey's Manual of Systematics of Archaea and Bacteria

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Phy.to.plas'ma. Gr. neut. n. phyton , a plant; Gr. neut. n. plasma something formed or molded, a form; N.L. neut. n. Phytoplasma , a form from a plant. Tenericutes / Mollicutes / Acholeplasmatales / Incertae Sedis ‐ Family II / Candidatus Phytoplasma The generic name ‘ Candidatus Phytoplasma’ has been adopted by specialists to refer to a monophyletic clade of wall‐less phytopathogenic bacteria affiliated with the order Acholeplasmatales in the class Mollicutes . These small (<1 µm) pleomorphic cells occur within the nutritionally‐rich phloem sap and sieve elements of plants, and in the gut or hemolymph of insects that feed on plants. Sustained culture in cell‐free media has not yet been demonstrated for any phytoplasma, and a recent report of successful axenic culture remains to be independently replicated. Reference strains are maintained in plants by periodic graft inoculation. Sequence analysis of PCR‐amplified rDNA, plus considerations of the plant host range and vector species, provide a basis for phytoplasma strain identification and assignment to phylogenetic groups. Hundreds of plant species are susceptible to infection, with signs including discoloration, stunting, virescence, phyllody, proliferation of flowers or shoots, or sterility. The necessity for strict quarantine regulations to control the spread of phytoplasmas among important plants such as fruit trees, palms, and grapevines illustrates the importance of accurate identification and nomenclature for these organisms.

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‘CandidatusPhytoplasma’

Gasparich¹,

Bertaccini²,

Zhao³

2020

Bergey's Manual of Systematics of Archaea and Bacteria

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Phy.to.plas‐ma. Gr. masc. n. phytos a plant; N.L. neut. n. Phytoplasma a form from a plant. Tenericutes / Mollicutes / Acholeplasmatales / Incertae sedis – Family II / Candidatus Phytoplasma Phytoplasmas are wall‐less, nutritionally fastidious, and phytopathogenic prokaryotes 0.2–0.8 μm in diameter that morphologically resemble nonhelical members of the class Mollicutes . Sequencing of nearly full‐length PCR‐amplified 16S rRNA genes, combined with earlier studies, provided the first comprehensive phylogeny of the organisms and showed that they constitute a unique, monophyletic clade within the Mollicutes . These organisms are most closely related to members of the genus Acholeplasma within the Anaeroplasma clade as defined by Weisburg et al. Despite decades of efforts and recent progress, sustained pure culture in cell‐free media has not yet been demonstrated for any phytoplasma. Their genome sizes have been estimated to range from 530 to 1,350 kb, and the DNA G + C content is about 23–30 mol%. The presence of a characteristic oligonucleotide sequence in the 16S rRNA gene, CAA GAY BAT KAT GTK TAG CYG GDC T, and standard codon usage indicate that phytoplasmas represent a distinct genus‐level taxon for which the name ‘ Candidatus Phytoplasma’ has been adopted. At present, for any subtaxa within the provisional genus, the designation ‘ Candidatus ’ must still be used. DNA G + C content (mol%) : 23–29.

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The infection of leafhoppers by western X-disease virus

Cited by 29 publications

References 21 publications

Evidence on Possible Mycoplasma Etiology of Aster Yellows Disease II. Suppression of Aster Yellows in Insect Vectors

Evidence on Possible Mycoplasma Etiology of Aster Yellows Disease II. Suppression of Aster Yellows in Insect Vectors

CandidatusPhytoplasma

‘CandidatusPhytoplasma’

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