Conidiophores of V. albo-atrum
In studies of V. albo-atrum, by the use of molecular analysis and pathogenicity tests, we have identified two types of isolates in our hop gardens: isolates (PG1), which induce a mild form of hop wilt and isolates (PG2), which kill the plants. Comparison of these two pathotypes with hop V. albo-atrum isolates from other European hop growing regions and isolates of V. albo-atrum from other hosts have shown genetic differentiation between all lethal and mild isolates, as well as isolates from other hosts and a close genetic relationship between our PG2 isolates and lethal hop isolates from England. Comparative analysis of mycelium proteomes of the two forms additionally show similarities between lethal pathotypes from Slovenia and England and mild pathotypes from the two countries, as well as differentially expressed proteins that might explain the increased virulence of the lethal pathotype. Preliminary studies of the genome size of lethal and mild isolates suggest that lethal isolates have larger genomes than mild types and pulse field electrophoresis has revealed different karyotypes for them.