Molecular evidence for the presence of Phaeomoniella chlamydospora in New Zealand nurseries, and its detection in rootstock mothervines using species-specific PCR

Phaeomoniella chlamydospora is considered to be the causal agent of Petri disease of grapevines. The source of primary inoculum is believed to be through the planting of grafted vines collected from infected mother rootstock vines. The presence of P. chlamydospora in New Zealand has been confirmed by analysis of the ribosomal gene region amplified from morphologically identified isolates. Sequencing of six of these isolates revealed that their nucleotide sequences were 99.9–100% similar to those reported in GenBank, and established that the species-specific primers, previously developed for overseas strains, would amplify the New Zealand isolates. A method for DNA extraction from grapevine wood was developed which, when combined with the species-specific primers, provides the basis for a diagnostic service for the detection of this disease in rootstock.