Infection of non-host model plant species with the narrow-host-range Cacao swollen shoot virus.

Cacao swollen shoot virus (CSSV) is a major pathogen of cacao (Theobroma cacao) in Africa, and long-standing efforts to limit its spread by the culling of infected trees have had very limited success. CSSV is a particularly difficult virus to study, as it has a very narrow host range, limited to several tropical tree species. Furthermore, the virus is not mechanically transmissible, and its insect vector can only be used with difficulty.

Evaluation of potential risks associated with recombination in transgenic plants expressing viral sequences.

Virus-resistant transgenic plants have been created primarily through the expression of viral sequences. It has been hypothesized that recombination between the viral transgene mRNA and the RNA of an infecting virus could generate novel viruses. As mRNA/viral RNA recombination can occur in virus-resistant transgenic plants, the key to testing this risk hypothesis is to compare the populations of recombinant viruses generated in transgenic and non-transgenic plants.

The plant pathogen Erwinia amylovora produces acyl-homoserine lactone signal molecules in vitro and in planta.

We report for the first time the production of acyl homoserine lactones (AHLs) by Erwina amylovora, an important quarantine bacterial pathogen that causes fire blight in plants. E. amylovora produces one N-acyl homoserine lactone [a N-(3-oxo-hexanoyl)-homoserine lactone or a N-(3-hydroxy-hexanoyl)-homoserine lactone] quorum sensing signal molecule both in vitro and in planta (pear plant).

Quorum sensing in the Burkholderia cepacia complex.

Quorum sensing is a cell-density-dependent regulatory mechanism which, in Gram-negative bacteria, usually involves the production and detection of N-acyl homoserine lactones (HSLs). In the last four years HSL-dependent quorum sensing has been identified in members of the Burkholderia cepacia complex, and this mini-review summarizes initial findings and discusses future perspectives.

Identification of quorum-sensing-regulated genes of Burkholderia cepacia.

Quorum sensing is a regulatory mechanism (operating in response to cell density) which in gram-negative bacteria usually involves the production of N-acyl homoserine lactones (HSL). Quorum sensing in Burkholderia cepacia has been associated with the regulation of expression of extracellular proteins and siderophores and also with the regulation of swarming and biofilm formation. In the present study, several quorum-sensing-controlled gene promoters of B.