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

Melamed, Sharon; Tanne, Edna; Ben-Haim, Raz; Edelbaum, Orit; Yogev, David; Sela, Ilan

doi:10.1128/jb.185.22.6513-6521.2003

Cited by 14 publications

(8 citation statements)

References 53 publications

(51 reference statements)

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“…This is also in agreement with annotations conducted for OY-M (76). Our results were not in agreement with a previous report that stated that UGA should be considered as a tryptophan codon in phytoplasmas, as in mycoplasmas (64). The average guanine (G) and cytosine (C) content of the AY-WB chromosome is 27%.…”

contrasting

confidence: 55%

Living with Genome Instability: the Adaptation of Phytoplasmas to Diverse Environments of Their Insect and Plant Hosts

Bai

Zhang

Ewing³

et al. 2006

J Bacteriol

350

447

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Phytoplasmas ("CandidatusPhytoplasmaThe phylogenetic tree of mollicutes is composed of two major clades that diverged early in evolution (51). One clade contains the orders Acholeplasmatales and Anaeroplasmatales (AAA clade mollicutes), and the other clade contains the orders Mycoplasmatales and Entomoplasmatales (SEM clade mollicutes) (9). Phytoplasmas, formerly known as mycoplasma-like organisms of plants, form a monophyletic group in the order Acholeplasmatales (51) and were recently assigned to a novel genus, "Candidatus Phytoplasma" (41). Approximately 20 phytoplasma phylogenetic groups have been proposed based on 16S rRNA gene sequences, and new branches are continuously being discovered (69,85). Members of the order Acholeplasmatales are distinct from other mollicutes in several ways. For instance, whereas most mollicutes use UGA as a tryptophan codon instead of a stop codon, a feature they share with mitochondria, the acholeplasmas and phytoplasmas retained UGA as a stop codon (80).

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contrasting

confidence: 55%

Living with Genome Instability: the Adaptation of Phytoplasmas to Diverse Environments of Their Insect and Plant Hosts

Bai

Zhang

Ewing³

et al. 2006

J Bacteriol

350

447

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“…In addition, although some of our sequences show high identity to sequences annotated as being from a phytoplasma, we believe this annotation is incorrect. The “phytoplasma” DNA was isolated from the saliva of the leafhopper Orosius albicinctus [ 33 ]. However, all the sequences in our sample that showed matches to sequences annotated as “phytoplasma”-like show phylogenetic relationships to the Bacteroidetes phylum.…”

Section: Resultsmentioning

confidence: 99%

Metabolic Complementarity and Genomics of the Dual Bacterial Symbiosis of Sharpshooters

Wu¹,

Daugherty²,

et al. 2006

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Mutualistic intracellular symbiosis between bacteria and insects is a widespread phenomenon that has contributed to the global success of insects. The symbionts, by provisioning nutrients lacking from diets, allow various insects to occupy or dominate ecological niches that might otherwise be unavailable. One such insect is the glassy-winged sharpshooter (Homalodisca coagulata), which feeds on xylem fluid, a diet exceptionally poor in organic nutrients. Phylogenetic studies based on rRNA have shown two types of bacterial symbionts to be coevolving with sharpshooters: the gamma-proteobacterium Baumannia cicadellinicola and the Bacteroidetes species Sulcia muelleri. We report here the sequencing and analysis of the 686,192–base pair genome of B. cicadellinicola and approximately 150 kilobase pairs of the small genome of S. muelleri, both isolated from H. coagulata. Our study, which to our knowledge is the first genomic analysis of an obligate symbiosis involving multiple partners, suggests striking complementarity in the biosynthetic capabilities of the two symbionts: B. cicadellinicola devotes a substantial portion of its genome to the biosynthesis of vitamins and cofactors required by animals and lacks most amino acid biosynthetic pathways, whereas S. muelleri apparently produces most or all of the essential amino acids needed by its host. This finding, along with other results of our genome analysis, suggests the existence of metabolic codependency among the two unrelated endosymbionts and their insect host. This dual symbiosis provides a model case for studying correlated genome evolution and genome reduction involving multiple organisms in an intimate, obligate mutualistic relationship. In addition, our analysis provides insight for the first time into the differences in symbionts between insects (e.g., aphids) that feed on phloem versus those like H. coagulata that feed on xylem. Finally, the genomes of these two symbionts provide potential targets for controlling plant pathogens such as Xylella fastidiosa, a major agroeconomic problem, for which H. coagulata and other sharpshooters serve as vectors of transmission.

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“…Genomic DNA is extracted by adding 10 µl of 0.5 M NaOH, followed by the addition of 20 µl of 1M Tris-HCl (pH 8.0) containing 1% sodium dodecyl sulfate and 20mM EDTA. The mixture is then incubated at 65°C for 15 min, precipitated with 2 volumes of ethanol, redissolved in 30 µl of TE, and kept at -80°C (18). The amounts of reagents are detailed for 200 µl of artificial diet and should be adjusted accordingly when using higher amounts of diets (e.g.…”

Section: Methodsmentioning

confidence: 99%

Insect Vector Transmission Assays

Bosco

Tedeschi

2012

Methods in Molecular Biology

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SummaryPhytoplasmas are transmitted in a persistent propagative manner by phloem-feeding vectors belonging to the order Hemiptera, suborder Homoptera. Following acquisition from the infected source plant, there is a latent period before the vector can transmit, so transmission assays consist of three basic steps: acquisition, latency and inoculation. More than ninety vector species (plant-, leafhoppers and psyllids) have been discovered so far but many others are still undiscovered, and their role in spreading economically important crop diseases is neglected. Therefore, screening for vectors is an essential step in developing rational control strategies for phytoplasma-associated diseases, targeted against the actual vectors. The mere detection of a phytoplasma in an insect does not imply that the insect is a vector; a transmission assay is required to provide conclusive evidence. Transmission experiments can be carried out using insects from phytoplasma-free laboratory colonies or field-collected. Moreover, transmission assays can be performed by feeding vectors on an artificial diet through Parafilm ® , then phytoplasmas can be detected in the sucrose feeding medium by PCR. Transmission trials involve the use of different techniques according to the biology of the different vector species, planthoppers, leafhoppers and psyllids.

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

Cited by 14 publications

References 53 publications

Living with Genome Instability: the Adaptation of Phytoplasmas to Diverse Environments of Their Insect and Plant Hosts

Living with Genome Instability: the Adaptation of Phytoplasmas to Diverse Environments of Their Insect and Plant Hosts

Metabolic Complementarity and Genomics of the Dual Bacterial Symbiosis of Sharpshooters

Insect Vector Transmission Assays

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