SYSTEMATICS OF ALTERNARIA SPP. ASSOCIATED WITH TREE FRUITS AND INTERNATIONAL COMMERCE
Physiology and Pathology of Tree Fruits Research
Project Number: 5350-22000-016-00
Start Date: Jun 04, 2007
End Date: Sep 30, 2011
The long-term objective of this project is to develop a stable, biologically relevant taxonomy for the genus Alternaria with particular reference to the small-spored members of the genus, which are the taxa most often involved in phytosanitary issues and which are also frequently misidentified. Associated with this objective is the development of molecular protocols for detection and identification of target species of phytosanitary importance that are based upon the systematics work. Certain species of Alternaria (e.g., A. gaisen, A. yaliinficiens) are currently known to have a limited geographic distribution that restricts the movement of deciduous tree fruit to the U.S. and other world markets. Other species, many of which are undescribed or frequently misidentified, occur in the United States and in other countries, and need to be characterized and described so that regulatory actions regarding Alternaria on intercepted plant products can be based upon a firm and scientific understanding of the Alternaria taxa that occur on tree fruits and other substrates in the U.S. Over the next 5 years we will focus on the following objective:
Objective 1: Isolate and accumulate sequence data from genomic transcripts of known
Alternaria spp. which are detected during development of phenotypic traits that vary among different sub-generic groups sensu Simmons and Roberts (1993) and species within those groups, with particular emphasis on sporulation pattern, conidial morphology and, if necessary, germination-mediated metabolite production.
A fundamental understanding of species-diversity (identity) among Alternaria strains associated with tree fruit will be developed using morphological characters and species-specific DNA sequences identified via subtractive hybridization protocols. Research will be conducted as necessary to address market- or issue-specific questions that arise from interactions with trading partners. Replacing 5350-22000-014-00D (11/03).