Mycoplasmas of Plants and Insects

Seemüller, E.; Garnier, M.; Schneider, Bernd

doi:10.1007/0-306-47606-1_5

Cited by 74 publications

(42 citation statements)

References 101 publications

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“…The expected size of the phytoplasma genome is only 500 to 1,200 kb (50). Therefore, the above-described genomic library (about 5,000 clones with an average insert size of approximately 2,000 bp) seems to be representative of the entire phytoplasmal genome, allowing the launch of a project to decipher the entire phytoplasmal genome.…”

Section: Discussionmentioning

confidence: 99%

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Identification and Characterization of Phytoplasmal Genes, Employing a Novel Method of Isolating Phytoplasmal Genomic DNA

et al. 2003

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Phytoplasmas are unculturable, insect-transmissible plant pathogens belonging to the class Mollicutes. To be transmitted, the phytoplasmas replicate in the insect body and are delivered to the insect's salivary glands, from where they are injected into the recipient plant. Because phytoplasmas cannot be cultured, any attempt to recover phytoplasmal DNA from infected plants or insects has resulted in preparations with a large background of host DNA. Thus, studies of the phytoplasmal genome have been greatly hampered, and aside from the rRNA genes, only a few genes have hitherto been isolated and characterized. We developed a unique method to obtain host-free phytoplasmal genomic DNA from the insect vector's saliva, and we demonstrated the feasibility of this method by isolating and characterizing 78 new putative phytoplasmal open reading frames and their deduced proteins. Based on the newly accumulated information on phytoplasmal genes, preliminary characteristics of the phytoplasmal genome are discussed.

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Section: Discussionmentioning

confidence: 99%

“…This method also allowed, for the first time, a comprehensive phytoplasma classification as the basis for an emerging taxonomy. Under the provisional status Candidatus, six species have been defined to date (16,19,26,28,49,50,55).…”

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Identification and Characterization of Phytoplasmal Genes, Employing a Novel Method of Isolating Phytoplasmal Genomic DNA

et al. 2003

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“…Witches' broom . Hormozgan Phytoplasmas are wall-less and phloem-restricted plant pathogens transmitted in nature by several groups of insects especially leafhoppers (Cicadellidae) (Seemüller et al 2002). They affect more than 600 plant species from tropical, subtropical to temperate climates all over the world (Jones 2002).…”

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confidence: 99%

First report of a ‘Candidatus Phytoplasma trifolii’-related strain associated with Suaeda aegyptiaca and its potential vector in Iran

Seyahooei

Hemmati

Faghihi

et al. 2017

Australasian Plant Dis. Notes

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Samples of Suaeda aegyptiaca with phytoplasma symptoms such as witches' broom, yellowing and little leaf were observed in Hormozgan Province, Iran in 2016. Using PCR assays, the symptomatic plants tested positive for phytoplasma. Results of phylogenetic analyses of the 16S rRNA gene sequences revealed that the phytoplasma associated with Suaeda aegyptiaca witches' broom (SaWT) is a strain of 'Candidatus Phytoplasma trifolii'. In addition, the phytoplasma was successfully detected in a leafhopper, Neoaliturus pulcher collected from the symptomatic plant by amplifying its 16S rRNA, which may indicate that this is a potential vector of this phytoplasma. This is the first report on the presence of a 'Ca. Phytoplasma trifolii'-related strain associated with S. aegyptiaca and the possible vector in Iran.Keywords Phytoplasma . Neoaliturus pulcher. Witches' broom . Hormozgan Phytoplasmas are wall-less and phloem-restricted plant pathogens transmitted in nature by several groups of insects especially leafhoppers (Cicadellidae) (Seemüller et al. 2002). They affect more than 600 plant species from tropical, subtropical to temperate climates all over the world (Jones 2002). Molecular analysis of several conserved genes, such as the 16S rRNA gene, has identified at least 32 groups and 100 subgroups of phytoplasmas (Nejat and Vadamalai 2013). Phytoplasmas in group 16SrVI, previously called the Clover proliferation (CP) group, were described associated with a disease of alsike clover in Canada originally associated with a yellows type virus (Chiykowski 1965). Subsequent investigations revealed that CP was in fact a phytoplasma that was also associated with phytoplasma diseases of tomato, potato, elm and pepper. CP is now taxonomically described as 'Ca. Phytoplasma trifolii' (Hiruki and Wang 2004). In Iran, some plants including Carthamus tinctorius, Cucumis sativus and Medicago sativa are known to be infected by 16SrVI phytoplasmas. In phytoplasma disease epidemics, insect vectors play a major role, which is not always easy to understand and interpret. Furthermore, polyphagous vectors have the potential to inoculate a wide range of plant species, which may differ in susceptibility (Weintraub and Beanland 2006).Suaeda aegyptiaca is a succulent, annual halophyte plant, which inhabits and is consider native to saline soils of arid and semiarid regions of Iran and widely distributed in Iraq, UAE, Pakistan and North Africa. In addition to supplying a salad, it is also a well-known medicinal plant for treating eczema in Iran (Askari et al. 2006).In September 2016, typical symptoms of phytoplasma disease, including witches' broom, yellowing and little leaf were observed during surveys in a S. aegyptiaca plant next to a cultivated vegetable field in Hassanlangi district, Hormozgan province, Iran (Fig. 1). A preliminary study was performed to determine if a phytoplasma was associated with the symptomatic plant. In addition, to find potential vectors of the related phytoplasma, all insects feeding on the symptomatic plant were ...

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“…Experimental transmission of these S. citri plasmid mutants through injection into the leafhopper vector Circulifer haematoceps revealed that pSci6, more precisely, the pSci6_06 coding sequence, encoding a protein of unknown function, was essential for transmission. In contrast, ScARPs and P32 were dispensable for both acquisition and transmission of the spiroplasmas by the leafhopper vector, even though S. citri mutants lacking pSci1 to -5 (encoding ScARPs) were acquired and transmitted at lower efficiencies than the wild-type strain GII3.Phytoplasmas and spiroplasmas, two groups of pathogenic mollicutes, are associated with many diseases affecting economically important crops, such as ornamentals, vegetables, fruit trees, and grapevine (6,10,26,36). Whereas most plantpathogenic bacteria colonize the apoplast of plant tissues, phytoplasmas and spiroplasmas are restricted to the phloem sieve tubes and are transmitted from plant to plant by phloem sapsucking insects (31, 42), which are therefore responsible for the spread of the diseases.…”

mentioning

confidence: 99%

“…Phytoplasmas and spiroplasmas, two groups of pathogenic mollicutes, are associated with many diseases affecting economically important crops, such as ornamentals, vegetables, fruit trees, and grapevine (6,10,26,36). Whereas most plantpathogenic bacteria colonize the apoplast of plant tissues, phytoplasmas and spiroplasmas are restricted to the phloem sieve tubes and are transmitted from plant to plant by phloem sapsucking insects (31, 42), which are therefore responsible for the spread of the diseases.…”

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confidence: 99%

Sequences Essential for Transmission of Spiroplasma citri by Its Leafhopper Vector, Circulifer haematoceps , Revealed by Plasmid Curing and Replacement Based on Incompatibility

Breton

Duret

Danet

et al. 2010

Appl Environ Microbiol

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Spiroplasma citri GII3 contains highly related low-copy-number plasmids pSci1 to -6. Despite the strong similarities between their replication regions, these plasmids coexist in the spiroplasma cells, indicating that they are mutually compatible. The pSci1 to -6 plasmids encode the membrane proteins known as S. citri adhesion-related proteins (ScARPs) (pSci1 to -5) and the hydrophilic protein P32 (pSci6), which had been tentatively associated with insect transmission, as they were not detected in non-insect-transmissible strains. With the aim of further investigating the role of plasmid-encoded determinants in insect transmission, we have constructed S. citri mutant strains that differ in their plasmid contents by developing a plasmid curing/ replacement strategy based on the incompatibility of plasmids having identical replication regions. Experimental transmission of these S. citri plasmid mutants through injection into the leafhopper vector Circulifer haematoceps revealed that pSci6, more precisely, the pSci6_06 coding sequence, encoding a protein of unknown function, was essential for transmission. In contrast, ScARPs and P32 were dispensable for both acquisition and transmission of the spiroplasmas by the leafhopper vector, even though S. citri mutants lacking pSci1 to -5 (encoding ScARPs) were acquired and transmitted at lower efficiencies than the wild-type strain GII3.Phytoplasmas and spiroplasmas, two groups of pathogenic mollicutes, are associated with many diseases affecting economically important crops, such as ornamentals, vegetables, fruit trees, and grapevine (6,10,26,36). Whereas most plantpathogenic bacteria colonize the apoplast of plant tissues, phytoplasmas and spiroplasmas are restricted to the phloem sieve tubes and are transmitted from plant to plant by phloem sapsucking insects (31, 42), which are therefore responsible for the spread of the diseases. Despite the fact they share common habitats with phytoplasmas, spiroplasmas are distinguishable in that they display a characteristic helical morphology and can be cultured in vitro. Spiroplasma citri is the etiological agent of citrus stubborn disease (33). It also infects many other plants, including the Madagascar periwinkle (Catharanthus roseus), an experimental host plant in which it induces symptoms such as stunting, leaf yellowing, and wilting, eventually leading to plant death. In nature, S. citri is transmitted in a circulative, persistent manner by the leafhoppers Circulifer haematoceps (Hemiptera, Cicadellidae) (in the Mediterranean area and the Near East) (16) and Circulifer tenellus (in the United States) (28).To complete their transmission cycle, spiroplasmas ingested by leafhopper vectors must cross two physical barriers, the gut epithelium (to move from the lumen to the hemocoel) and then the salivary gland-associated membranes (to reach the salivary duct) (24,27). Mainly on the basis of electron microscopy observations, a hypothetical model in which spiroplasmas pass through these two barriers by an endocytosis-exocytosis pro...

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Mycoplasmas of Plants and Insects

Cited by 74 publications

References 101 publications

Identification and Characterization of Phytoplasmal Genes, Employing a Novel Method of Isolating Phytoplasmal Genomic DNA

Identification and Characterization of Phytoplasmal Genes, Employing a Novel Method of Isolating Phytoplasmal Genomic DNA

First report of a ‘Candidatus Phytoplasma trifolii’-related strain associated with Suaeda aegyptiaca and its potential vector in Iran

Sequences Essential for Transmission of Spiroplasma citri by Its Leafhopper Vector, Circulifer haematoceps , Revealed by Plasmid Curing and Replacement Based on Incompatibility

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