The most common practices are the spraying of various insecticides to control insect vectors, and removal of symptomatic plants. Phytoplasma-resistant cultivars are not available for the vast majority of affected crops.

The minimal gene set essential for life has long been sought. We report the 860-kb genome of the obligate intracellular plant pathogen phytoplasma (Candidatus Phytoplasma asteris, OY strain). The phytoplasma genome encodes even fewer metabolic functions than do mycoplasma genomes. It lacks the pentose phosphate cycle and, more unexpectedly, ATP-synthase subunits, which are thought to be essential for life. This may be the result of reductive evolution as a consequence of life as an intracellular parasite in a nutrient-rich environment.

One of the most important themes in agricultural science is the identification of virulence factors involved in plant disease. Here, we show that a single virulence factor, tengu-su inducer (TENGU), induces witches' broom and dwarfism and is a small secreted protein of the plant-pathogenic bacterium, phytoplasma. When tengu was expressed in Nicotiana benthamiana plants, these plants showed symptoms of witches' broom and dwarfism, which are typical of phytoplasma infection. Transgenic Arabidopsis thaliana lines expressing tengu exhibited similar symptoms, confirming the effects of tengu expression on plants. Although the localization of phytoplasma was restricted to the phloem, TENGU protein was detected in apical buds by immunohistochemical analysis, suggesting that TENGU was transported from the phloem to other cells. Microarray analyses showed that auxin-responsive genes were significantly down-regulated in the tengu-transgenic plants compared with GUS-transgenic control plants. These results suggest that TENGU inhibits auxin-related pathways, thereby affecting plant development.auxin ͉ disease symptom ͉ morphological change ͉ phytoplasma

Anisotropy in the arrival directions of cosmic rays with energies above 10 17 eV is studied using data from the Akeno 20 km 2 array and the Akeno Giant Air Shower Array (AGASA), using a total of about 114,000 showers observed over 11 years. In the first harmonic analysis, we have found strong anisotropy of ∼ 4% around 10 18 eV, corresponding to a chance probability of ∼ 0.2% after taking the number of independent trials into account. With two dimensional analysis in right ascension and declination, this anisotropy is interpreted as an excess of showers near the directions of the Galactic Center and the Cygnus region.

Many insect-transmissible pathogens are transmitted by specific insect species and not by others, even if they are closely related. The molecular mechanisms underlying such strict pathogen-insect specificity are poorly understood. Candidatus Phytoplasma asteris, OY strain, line W (OY), is a phytopathogenic bacterium transmitted from plant to plant by sap-feeding insect vectors (leafhoppers). Our study focused on an abundant cell-surface membrane protein of the phytoplasma named antigenic membrane protein (Amp), which is not homologous with any reported functional protein.Immunofluorescence microscopy of the phytoplasma-infected insect showed that OY phytoplasma was localized to the microfilaments of the visceral smooth muscle surrounding the insect's intestinal tract. The affinity column assay showed that Amp forms a complex with three insect proteins: actin, myosin heavy chain, and myosin light chain. Amp-microfilament complexes were detected in all OY-transmitting leafhopper species, but not in the non-OY-transmitting leafhoppers, suggesting that the formation of the Amp-microfilament complex is correlated with the phytoplasma-transmitting capability of leafhoppers. Although several studies have reported interactions between pathogens and mammalian microfilaments, this is an example of host-specific interactions between a bacterial surface protein and a host microfilament in insect cells. Our data also suggest that the utilization of a host microfilament may be a universal system for pathogenic bacteria infecting mammals or insects.host determination ͉ microbiology ͉ pathogen-host interaction ͉ phytoplasma

Phylogenetic relationships of five jujube witches'-broom (JWB) phytoplasma isolates from four different districts, and other phytoplasmas, were investigated by 16S rDNA PCR amplification and sequence analysis. The 16S rDNA sequences of any pair of the five isolates of JWB phytoplasmas were >99?5 % similar. The JWB phytoplasma 16S rDNA sequences were most closely related to that of the elm yellows (EY) phytoplasma in 16S-group VIII. Phylogenetic analysis of the 16S rDNA sequences from the JWB phytoplasma isolates, together with sequences from most of the phytoplasmas archived in GenBank, produced a tree in which the JWB isolates clustered as a discrete subgroup. The uniqueness of the JWB phytoplasma appears to be correlated with a specific insect vector (Hishimonus sellatus) and the host plant (Zizyphus jujuba), or with a specific geographical distribution. The unique properties of the JWB phytoplasma sequences clearly indicate that it represents a novel taxon, 'Candidatus Phytoplasma ziziphi'.

c Here, we investigate the endosymbiotic microbiota of the Macrosteles leafhoppers M. striifrons and M. sexnotatus, known as vectors of phytopathogenic phytoplasmas. PCR, cloning, sequencing, and phylogenetic analyses of bacterial 16S rRNA genes identified two obligate endosymbionts, "Candidatus Sulcia muelleri" and "Candidatus Nasuia deltocephalinicola," and five facultative endosymbionts, Wolbachia, Rickettsia, Burkholderia, Diplorickettsia, and a novel bacterium belonging to the Rickettsiaceae, from the leafhoppers. "Ca. Sulcia muelleri" and "Ca. Nasuia deltocephalinicola" exhibited 100% infection frequencies in the host species and populations and were separately harbored within different bacteriocytes that constituted a pair of coherent bacteriomes in the abdomen of the host insects, as in other deltocephaline leafhoppers. Wolbachia, Rickettsia, Burkholderia, Diplorickettsia, and the novel Rickettsiaceae bacterium exhibited infection frequencies at 7%, 31%, 12%, 0%, and 24% in M. striifrons and at 20%, 0%, 0%, 20%, and 0% in M. sexnotatus, respectively. Although undetected in the above analyses, phytoplasma infections were detected in 16% of M. striifrons and 60% of M. sexnotatus insects by nested PCR of 16S rRNA genes. Two genetically distinct phytoplasmas, namely, "Candidatus Phytoplasma asteris," associated with aster yellows and related plant diseases, and "Candidatus Phytoplasma oryzae," associated with rice yellow dwarf disease, were identified from the leafhoppers. These results highlight strikingly complex endosymbiotic microbiota of the Macrosteles leafhoppers and suggest ecological interactions between the obligate endosymbionts, the facultative endosymbionts, and the phytopathogenic phytoplasmas within the same host insects, which may affect vector competence of the leafhoppers.

A gene that encodes a putative SecE protein, which is a component of the Sec protein-translocation system, was cloned from the onion yellows phytoplasma (OY). The identification of this gene and the previously reported genes encoding SecA and SecY provides evidence that the Sec system exists in phytoplasma. In addition, a gene encoding an antigenic membrane protein (Amp) (a type of immunodominant membrane protein) of OY was cloned and sequenced. The OY amp gene consisted of 702 nt encoding a protein of 233 aa which was highly similar to Amp of aster yellows phytoplasma (AY). Part of OY Amp was overexpressed in Escherichia coli, purified, and used to raise an anti-Amp polyclonal antibody. The anti-Amp antibody reacted specifically with an OY-infected plant extract in Western blot analysis and was therefore useful for the detection of OY as well as Amp. Amp has a conserved protein motif that is known to be exported by the Sec system of E. coli. A partial OY Amp protein expressed in E. coli was localized in the periplasm as a shorter, putatively processed form of the protein. It had probably been exported from the cytoplasm to the periplasm through the Sec system. Moreover, OY Amp protein expressed in OY and detected in OY-infected plants was apparently also processed. Because phytoplasmas cannot be cultured or transformed, little information is available regarding their protein secretion systems. This study suggests that the Sec system operates in this phytoplasma to export OY Amp.