Plant Pathology (2007) 56, 448-463
M.A. Whitelaw-Weckert, S.J. Curtin, R. Huang, C.C. Steel, C.L. Blanchard and P.E. Roffey (2007)
Phylogenetic relationships and pathogenicity of Colletotrichum acutatum isolates from grape in subtropical Australia
Plant Pathology 56 (3), 448-463
Abstract: The identity of Colletotrichum acutatum as the causal pathogen of grape ripe-rot, which causes yield loss and a bitter taint that lowers wine quality in Australian subtropical wine-grape regions, was confirmed using species-specific primers. Cultural, morphological and molecular methods (RAPD-PCR and sequencing of parts of the 5·8S-ITS regions and the ß-tubulin-2 gene) were used to determine the phylogenetic relationships of Australian C. acutatum isolates from wine grapes and other horticultural crops. A combination of RAPD-PCR and ß-tubulin-2 gene data showed that all wine-grape ripe-rot isolates from northern regions of New South Wales (NSW) and Queensland belong to a proposed new C. acutatum group (A9), together with isolates from Australian strawberry, mango, blueberry and olive. The 5·8S-ITS sequences for these grape pathogens were identical to published sequences for an isolate from Cyclamen (the Netherlands) and differed by 1 bp from isolates from Capsicum (Taiwan) and orange (Costa Rica). The grape ripe-rot isolates from the Shoalhaven Valley (southern NSW) were clustered within two other C. acutatum groups: A2 and A5. In vitro infection studies showed that Australian C. acutatum isolates from almond, blueberry, chilli, grape, mango, olive, strawberry and tomato were able to infect grape and could also infect blueberry and strawberry, indicating a lack of host specificity. This lack of host specificity, the genetic similarity with non-grape isolates, and the fact that many of the non-grape hosts were isolated from wine-growing regions, suggest the potential for cross-infection between grape and other horticultural crops.
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Database assignments for author(s): Melanie A. Whitelaw-Weckert, Christopher C. Steel
Research topic(s) for pests/diseases/weeds:
general biology - morphology - evolution
molecular biology - genes
