Genetic variation within New Zealand populations of Phaeomoniella chlamydospora, the causal agent of petri vine decline: a dissertation submitted in partial fulfilment of the requirements for the degree of Bachelor of Science, Honours at Lincoln University

The aim of this study was to characterise the genetic variation within 45 New Zealand isolates of Phaeomoniella chlamydospora and compare this to six isolates from Italy using the molecular techniques of randomly amplified polymorphic DNA (RAPD), randomly amplified microsatellite (RAMS) DNA and universally primed polymerase chain reaction (UP-PCR). Overall, genetic variation between New Zealand and Italian isolates of P. chlamydospora was low with a maximum of two genetically different groups, differing by only one band, identified using RAPD and UP-PCR primers. No polymorphism was detected using the RAMS method. Inter- and intravine variation was detected in New Zealand isolates, with three new groups, possibly unique to New Zealand, identified. New Zealand isolates had similar banding profiles to those of the Italian isolates. A subset of five New Zealand and one Italian isolate were further investigated for genetic variation using mycelial compatibility groups (MCG). One MCG was identified, which supported the molecular results of low genetic variation within P. chlamydospora isolates. The low genetic variation and the similar band profiles between New Zealand and Italian isolates suggested that asexual reproduction predominates in this fungus. The presence of intravine variation in the New Zealand regions sampled suggested that multiple introductions have occurred. The UP-PCR primer 3-2 produced a potential isolate-specific marker. Database searches of the translated protein sequence of the isolate-specific marker indicated significant homology to a group of flavin-binding monooxygenase-like proteins, which contained a putative NADP binding site. This is the first report of the presence in P. chlamydospora of a gene encoding a protein involved in an aflatoxin-like pathway. Determination of the presence of toxin production and related physiological responses in P. chlamydospora would assist in elucidating pathogenic processes within this pathogen