Phytoplasmas are insect-vectored bacteria that cause disease in a wide range of plant species. The increasing availability of molecular DNA analyses, expertise and additional methods in recent years has led to a proliferation of discoveries of phytoplasma-plant host associations and in the numbers of taxonomic groupings for phytoplasmas. The widespread use of common names based on the diseases ...

Phytoplasmas associated with cucumber phyllody (CuP) and squash phyllody (SqP) in Yazd province of Iran were characterized by molecular analyses and biological studies. Orosius albicinctus leafhoppers testing positive for phytoplasma presence by polymerase chain reaction (PCR) successfully transmitted CuP and SqP phytoplasmas to healthy cucumber and squash plants. The phytoplasmas were also tra...

Rubus stunt is an economically important disease in the production of raspberries, blackberries, and loganberries. A fast, sensitive, and reliable diagnosis of phytoplasmas, the causal agent of the disease, is of prime importance to stop its spread by vegetative propagation and by insect vectors. Therefore, multiplex qPCR assays using TaqMan probes with different kinds of fluorophores in one re...

The principal means of dissemination of phytoplasmas is by insect vectors. The interactions between phytoplasmas and their insect vectors are, in some cases, very specific, as is suggested by the complex sequence of events that has to take place and the complex form of recognition that this entails between the two species. The commonest vectors, or at least those best known, are members of the ...

Polymerase chain reaction (PCR)-based detection strategies were adopted to examine the etiology and vectorship of pear decline in Taiwan (PDTW). 16S rDNA sequences were amplified from total DNAs prepared from PDTW-affected pear trees Pyrus serotina Rehd. cv. Hengshan and pear psyllid Cacopsylla chinensis using PCR. According to the sequence analyses, C. chinensis carried phytoplasmas of two 16S...

Phytoplasmas ("Candidatus Phytoplasma," class Mollicutes) cause disease in hundreds of economically important plants and are obligately transmitted by sap-feeding insects of the order Hemiptera, mainly leafhoppers and psyllids. The 706,569-bp chromosome and four plasmids of aster yellows phytoplasma strain witches' broom (AY-WB) were sequenced and compared to the onion yellows phytoplasma strai...

Rubus stunt, a disease associated with phytoplasma infections in wild and cultivated Rubus species, is a major challenge in the production of raspberries, blackberries, and loganberries. Phytoplasmas are cell wall-less bacteria inhabiting the phloem and are transferred by phloem feeding insects. As the time between infection of a plant and the development of disease symptoms can take up to 1 ye...

Phytoplasmas are bacterial plant pathogens that have devastating effects on the yields of crops and plants worldwide. They are intracellular parasites of both plants and insects, and are spread among plants by insects. How phytoplasmas can adapt to two diverse environments is of considerable interest; however, the mechanisms enabling the "host switching" between plant and insect hosts are poorl...

Apple proliferation (AP), pear decline (PD) and European stone fruit yellows (ESFY) are among the most economically important plant diseases that are caused by phytoplasmas. Phylogenetic analyses revealed that the 16S rDNA sequences of strains of each of these pathogens were identical or nearly identical. Differences between the three phytoplasmas ranged from 1.0 to 1.5% of nucleotide positions...

Phytoplasmas cannot be cultivated in vitro, and remain the most poorly understood plant pathogens. Despite this limitation, the investigation of their nature with the aid of modern tools has produced noteworthy results during the last 20 years. Using biochemical and molecular approaches, the phylogeny of the phytoplasmas has been described, their chromosomal and extrachromosomal components are ...