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Host Range, Biological Variation, and Phylogenetic Diversity of Eutypa lata in California

Trouillas, F.P., Gubler, W.D.
Phytopathology 2010 v.100 no.10 pp. 1048-1056
Eutypa, plant pathogenic fungi, fungal diseases of plants, host plants, host range, species differences, fruit crops, ornamental plants, wild plants, indigenous species, phenotypic variation, phylogeny, strain differences, ribosomal DNA, internal transcribed spacers, microbial genetics, genes, pathogen identification, sequence analysis, geographical variation, pathogenicity, California
The objectives of this study were to investigate the host range of Eutypa lata in the major grape-growing regions in California and to analyze the phenotypic variation and phylogenetic diversity of E. lata isolates. Perithecia of E. lata were found on grapevines, in apricot, almond, cherry, apple, and pear tree orchards, and on ornamentals (oleander) and native plant species (California buckeye, big leaf maple, and willow). Multigene phylogenies of ribosomal DNA internal transcribed spacer, β-tubulin, and RPB2 genes confirmed the identity of E. lata recovered from the various host plants but also revealed sequence differences among isolates. The intraspecific phylogenetic diversity of E. lata did not correspond to geography or source of isolation, and intraspecific groups were not consistent across the different DNA phylogenies. Significant phenotypic variation also was detected among E. lata isolates, including ascospore and conidium length as well as level of aggressiveness on grapevines. Pathogenicity studies proved that all isolates were infectious to grapevine, suggesting that the native vegetation surrounding vineyards can serve as inoculum sources that may constitute an important element in the epidemiology of Eutypa dieback in grapevines.