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ABSTRACT: Molecular systematics of phialophora-like fungi from declining grapevines

2003. Leslie A. Long, Elwin L. Stewart, Nancy G. Wenner, Barrie E. Overton. 8 th International Congress of Plant Pathology . New Zealand.

The status and causes of grapevine decline in the states of Pennsylvania and New York ( USA ) have been under investigation since March of 2001. A survey has been conducted, across these two states, revealing the extent of vine decline in the region. From each site visited, wood tissue samples were taken from the trunk and roots of declining vines and plated onto 2% acidified malt agar. Fungi frequently identified from these symptomatic vines included Phaeomoniella chlamydospora, Phaeoacremonium spp. , Phialophora spp., and phialophora-like isolates. The objectives of this research are to assess the genetic diversity of selected phialophora-like isolates, and to determine the role of these organisms in grapevine decline. Molecular sequence data from the internal transcribed spacer (ITS) region ITS1-5.8S-ITS2, the large exon of translation elongation factor 1 a (tef), and the partial sequence of reverse polymerase subunit 2 (RPB2) gene regions have been analyzed using PAUP with Phaeomoniella chlamydospora as the out group. The phialophora-like isolates cluster in two clades: a Phialophora clade, and a Phaeoacremonium clade. The phialophora-like isolates clustering in the Phaeoacremonium clade do not match published sequences of Phaeoacremonium . Based on the sequence data, phialophora-like isolates clustering in the Phaeoacremonium clade will be preferentially selected for pathogenicity testing.