Diversity of Virulence in Phytophthora parasitica on Tobacco, as Reflected by Nuclear RFLPs.

ABSTRACT A worldwide collection of P. parasitica isolates was investigated for the ability to infect tobacco and tomato, as related to elicitin production. Elicitin was produced by all nontobacco isolates, and nonproducing strains all were isolated from tobacco.

Enzyme-Linked Immunosorbent Assay Testing of Shoots Grown In Vitro and the Use of Immunocapture-Reverse Transcription-Polymerase Chain Reaction Improve the Detection of Prunus necrotic ringspot virus in Rose.

We developed and evaluated two different methods to improve the detection of the most prevalent virus of rose in Europe, Prunus necrotic ring-spot virus (PNRSV). Immunocapture-reverse transcription-polymerase chain reaction was estimated to be about 100 times more sensitive than double-antibody sandwich-enzyme-linked immunosorbent assay (DAS-ELISA) and showed an equivalent specificity. Based on the observation that PNRSV multiplies actively in young growing tissues (axillary shoots and cuttings), an in vitro culture method allowing rapid (about 15 days) and homogeneous development of dormant axillary buds with high virus titers was standardized.

Survey of Prunus necrotic ringspot virus in Rose and Its Variability in Rose and Prunus spp.

ABSTRACT A survey for viruses in rose propagated in Europe resulted in detection of only Prunus necrotic ringspot virus (PNRSV) among seven viruses screened. Four percent of cut-flower roses from different sources were infected with PNRSV. Progression of the disease under greenhouse conditions was very slow, which should make this virus easy to eradicate through sanitary selection.

First Report of Cucumber mosaic virus in Teucrium fruticans.

Teucrium fruticans (shrubby germander), family Lamiaceae, is a hardy shrub. Being drought tolerant, it is widespread in the Mediterranean area. Because it is readily propagated through cuttings, it is also planted in hedges.

Developmental regulated mechanisms affect the ability of a fungal pathogen to infect and colonize tobacco leaves.

During tobacco development, a transition state from susceptibility to resistance to fungal pathogen infection is observed. Leaves acquire resistance to Phytophthora parasistica when the plant becomes committed to flowering. The ability to develop resistance does not imply pathogen-induced defence responses as for the onset of systemic acquired resistance (SAR).