ABSTRACT: Molecular phylogenetics of grapevine decline fungi from Pennsylvania and New York

B.E. Overton, E.L. Stewart and N.G. Wenner

Twenty-seven vineyard sites including more than 500 acres of vines were examined over three growing seasons (2001-03) to quantify the extent of vine decline and to isolate fungi from declining vineyards. Three hundred sixty-two fungal isolates were recovered from vines exhibiting decline symptoms in Pennsylvania (PA) and New York (NY). Twenty-nine percent of the fungi isolated were those associated with Petri disease. Phaeomoniella chlamydospora, Phaeoacremonium aleophilum, Phaeoacremonium mortoniae, Phaeoacremonium rubrigenum and Phaeoacremonium angustius/viticola were identified by morphological and molecular characters. Phaeoacremonium inflatipes and P. parisiticum were not isolated from declining vines in PA or NY. Twenty-four percent of the fungi isolated were Phialophora-like, referable to the genera Cadophora, Harpophora, and Phialophora s.s.. Twenty four percent were pycnidial fungi, with 8% identified to the genus Phomopsis. To date, the ITS rDNA gene region has been sequenced for 96 of the 362 isolates. Data obtained from the ITS rDNA region will be used to determine target strains for further phylogenetic study, including phylogenetic analyses based on other gene regions. Cadophora and Harpophora species were isolated in high frequency from declining vines and consequently, will be included in the overall sequencing project. The end result will be an established culture collection that can be used for ecological and plant pathological studies, and generation of sequence data that can be used for regional phylogenetic analyses, for identification of potentially new species, and for developing pathogen detection systems (real-time PCR).