Phytoplasmas, biotrophic wall-less prokaryotes, only reside in sieve elements of their host plants. The essentials of the intimate interaction between phytoplasmas and their hosts are poorly understood, which calls for research on potential ultrastructural modifications. We investigated modifications of the sieve-element ultrastructure induced in tomato plants by 'Candidatus Phytoplasma solani,...

Complex multi-trophic interactions in vectorborne diseases limit our understanding and ability to predict outbreaks. Arthropod-vectored pathogens are especially problematic, with the potential for novel interspecific interactions during invasions. Variations and novelties in plant-arthropod-pathogen triumvirates present significant threats to global food security. We examined aspects of a phyto...

Phytoplasma infection causes a desirable branching phenotype in the ornamental plant Euphorbia pulcherrima by releasing apical dominance. Four E. pulcherrima genes specifically regulated during phytoplasma infection were identified using differential display of cDNA-PCR products. According to BLAST searches the possible functions of the identified genes included a histidinecontaining phosphotra...

ABSTRACT In the spring of 2000, an aster yellows (AY) epidemic occurred in carrot crops in the Winter Garden region of southwestern Texas. A survey revealed that vegetable crops, including cabbage, onion, parsley, and dill, and some weeds also were infected by AY phytoplasmas. Nested polymerase chain reaction (PCR) and restriction fragment length polymorphism analysis of PCR-amplified phytoplas...

Polymerase chain reaction (PCR) with subsequent restriction fragment length polymorphism (RFLP) analysis is often used for phytoplasma identification and classification. Although these techniques are very sensitive and specific, in some cases, nonspecific reactions, false positives and negatives results, as well as unusual or illegible profiles after RFLP analyses, amplification of plant host ́s...

Phytoplasmas are cell-wall-less members of the bacterial class Mollicutes that are obligate parasites of plants and insect vectors. Phytoplasmas cause hundreds of plant diseases, several of which have worldwide agricultural significance (17). The plant host range of some phytoplasma strains may be very wide. This is the case for X-disease phytoplasma (Xp). Although X-disease is an economic dise...

Paulownia witches' broom (PaWB) caused by phytoplasma might result in devastating damage to the growth and wood production of Paulownia. To study the effect of phytoplasma on DNA sequence and to discover the genes related to PaWB occurrence, DNA polymorphisms and DNA methylation levels and patterns in PaWB seedlings, the ones treated with various concentration of methyl methane sulfonate (MMS) ...

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 symp...

Quercetin is known to possess antimicrobial activity against bacteria, fungi, and viruses. The activity of this flavonoid against phytoplasmas, non-cultivable plant pathogenic bacteria that cause numerous plant diseases, has never been examined before. The aim of this research was to examine the effect of different concentrations of quercetin (10 mM, 100 mM and 1 mM) on 'Candidatus Phytoplasma ...

Parasitic bacteria that infect eukaryotes, such as animals and plants, often have reduced genomes, having lost important metabolic genes as a result of their host-dependent life cycles. Genomic sequencing of these bacteria has revealed their survival strategies and adaptations to parasitism. Phytoplasmas (class Mollicutes, genus 'Candidatus Phytoplasma') are intracellular bacterial pathogens of...