Positive Selection Acting on a Surface Membrane Protein of the Plant-Pathogenic Phytoplasmas

Kakizawa, Shigeyuki; Oshima, Kenro; Jung, Hee‐Young; Suzuki, Shiho; Nishigawa, Hisashi; Arashida, Ryo; Miyata, Sumiko; Ugaki, Masashi; Kishino, Hirohisa; Namba, Susumu

doi:10.1128/jb.188.9.3424-3428.2006

Cited by 65 publications

(59 citation statements)

References 25 publications

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“…Phytoplasmas within the "Ca. Phytoplasma asteris" species carry genes that encode two immunodominant membrane proteins, Imp and Amp (14), and both of the genes encoding those proteins are objects of positive selection (13,47). The amp transcripts were the most abundant of all the analyzed gene transcripts in all three host species, and the amp transcript levels decreased in A. thaliana and M. quadripunctulatus during the CYP infection cycle.…”

Section: Discussionmentioning

confidence: 92%

Decreasing Global Transcript Levels over Time Suggest that Phytoplasma Cells Enter Stationary Phase during Plant and Insect Colonization

Pacifico

Galetto

Rashidi

et al. 2015

Appl Environ Microbiol

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To highlight different transcriptional behaviors of the phytoplasma in the plant and animal host, expression of 14 genes of "Candidatus Phytoplasma asteris," chrysanthemum yellows strain, was investigated at different times following the infection of a plant host (Arabidopsis thaliana) and two insect vector species (Macrosteles quadripunctulatus and Euscelidius variegatus). Target genes were selected among those encoding antigenic membrane proteins, membrane transporters, secreted proteins, and general enzymes. Transcripts were detected for all analyzed genes in the three hosts; in particular, those encoding the antigenic membrane protein Amp, elements of the mechanosensitive channel, and two of the four secreted proteins (SAP54 and TENGU) were highly accumulated, suggesting that they play important roles in phytoplasma physiology during the infection cycle. Most transcripts were present at higher abundance in the plant host than in the insect hosts. Generally, transcript levels of the selected genes decreased significantly during infection of A. thaliana and M. quadripunctulatus but were more constant in E. variegatus. Such decreases may be explained by the fact that only a fraction of the phytoplasma population was transcribing, while the remaining part was aging to a stationary phase. This strategy might improve long-term survival, thereby increasing the likelihood that the pathogen may be acquired by a vector and/or inoculated to a healthy plant. Phytoplasmas are wall-less plant-pathogenic bacteria, classified as "Candidatus Phytoplasma" spp. (1). They belong to the class Mollicutes and infect a wide variety of plants, causing heavy crop losses in many different countries (2). Phytoplasmas are phloem limited in the infected plant, and they cause severe symptoms (yellowing, dwarfism, and phyllody), often leading to plant death. They are transmitted by phloem-feeding Hemipteran vectors (leafhoppers, planthoppers, and psyllids) in a persistent propagative manner (3).Phytoplasmas are obligate parasites that depend on host cells for the uptake of essential compounds such as sugars, amino acids, ions, and nucleotide precursors (4). Consistent with this lifestyle, phytoplasmas have very small, A/T-rich genomes, ranging from 530 to 1,350 kb in size (5), that lack essential metabolic pathways, such as ATP synthesis. This genome condensation reflects the phytoplasma adaptation to nutrient-rich environments such as the plant phloem (6) and helps explain why these pathogens are not cultivable under axenic conditions (7).Although the pathogenicity mechanisms are still largely unclear, phytoplasmas influence plant metabolism both directly, through a set of membrane proteins acting as molecular carriers (6), and indirectly, through secretion of effector proteins (8,9). In vitro studies have also shown that phytoplasma immunodominant membrane proteins interact with vector proteins (10, 11) and plant proteins (12) and are subjected to strong positive selection (13-15). Moreover, phytoplasmas can modulate their genome express...

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Section: Discussionmentioning

confidence: 92%

Decreasing Global Transcript Levels over Time Suggest that Phytoplasma Cells Enter Stationary Phase during Plant and Insect Colonization

Pacifico

Galetto

Rashidi

et al. 2015

Appl Environ Microbiol

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“…Candidatus phytoplasma asteris OY (OY-M [AP006628] and OY-W) was maintained as described previously (Oshima et al, 2001). Samples of DNA from PPT, ACLR, and KV strains (Kakizawa et al, 2006) were kindly provided by Dr. A. Bertaccini (University of Bologna). Infected plants of PaWB, sumac witches' broom phytoplasma, GY, and MD strains (Kakizawa et al, 2006) were kindly provided by Drs.…”

Section: Phytoplasma Strains and Plant Materialsmentioning

confidence: 99%

The Alteration of Plant Morphology by Small Peptides Released from the Proteolytic Processing of the Bacterial Peptide TENGU

et al. 2013

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Phytoplasmas are insect-borne plant pathogenic bacteria that alter host morphology. TENGU, a small peptide of 38 residues, is a virulence factor secreted by phytoplasmas that induces dwarfism and witches' broom in the host plant. In this study, we demonstrate that plants process TENGU in order to generate small functional peptides. First, virus vector-mediated transient expression demonstrated that the amino-terminal 11 amino acids of TENGU are capable of causing symptom development in Nicotiana benthamiana plants. The deletion of the 11th residue significantly diminished the symptom-inducing activity of TENGU, suggesting that these 11 amino acids constitute a functional domain. Second, we found that TENGU undergoes proteolytic processing in vitro, generating peptides of 19 and 21 residues including the functional domain. Third, we observed similar processing of TENGU in planta, and an alanine substitution mutant of TENGU, for which processing was compromised, showed reduced symptom induction activity. All TENGU homologs from several phytoplasma strains possessed similar symptom induction activity and went through processing, which suggests that the processing of TENGU might be related to its function.

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“…For these proteins, the F-box domain attaches to ubiquitin and promotes proteasomal degradation Lomma et al, 2010 . The F-box domain gene is involved in the interaction with the host and the host-parasite interactions would promote diversification of even eukaryotic-derived proteins in arms race coevolutionary conflicts Blanc et al, 2005;Kakizawa et al, 2006 . The clear positive selections imply an important biological role for F-box domain in hostbacterium interactions, and indicate that the eukaryotic like protein in L. pneumophila is variable and thus account for strain differences.…”

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confidence: 99%

Positive Selection in F-Box Domain (lpp0233) Encoded in <i>Legionella pneumophila</i> Strains

et al. 2018

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Recent studies have shown that the genome of Legionella pneumophila is characterized by many foreign genes from a variety of eukaryotes. The eukaryotic like proteins are known to play a role in its multiplication within host cells; however, their evolutionary genetics of L. pneumophila in environments is unknown. In this study, we examined the nonsynonymous/synonymous substitution rate of eukaryotic like domain encoding genes among L. pneumophila strains. In silico analysis revealed that the nonsynonymous/synonymous substitution rate in F-box domain gene lpp0233 was higher than those in other eukaryotic like domain and protein encoding genes and housekeeping genes. The F-box domain gene sequences in L. pneumophila strains isolated from a natural hot spring were more diversified than those of previously known strains, owing to preferential positive selection.

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Positive Selection Acting on a Surface Membrane Protein of the Plant-Pathogenic Phytoplasmas

Cited by 65 publications

References 25 publications

Decreasing Global Transcript Levels over Time Suggest that Phytoplasma Cells Enter Stationary Phase during Plant and Insect Colonization

Decreasing Global Transcript Levels over Time Suggest that Phytoplasma Cells Enter Stationary Phase during Plant and Insect Colonization

The Alteration of Plant Morphology by Small Peptides Released from the Proteolytic Processing of the Bacterial Peptide TENGU

Positive Selection in F-Box Domain (lpp0233) Encoded in <i>Legionella pneumophila</i> Strains

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