Phylogeny of the pecan scab fungus Fusicladium effusum G. Winter based on the cytochrome b gene sequence
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Pecan scab, caused by the fungus Fusicladium effusum, is the most devastating disease of pecan (Carya illinoinensis) trees and is responsible for the majority of disease management efforts applied to that crop. The taxonomy of the fungus changed several times in the last decade and most recently, using ITS nrDNA data and conventional taxonomic methods, the organism was renamed F. effusum. In our study, a conserved region of the mitochondrial cytochrome b gene was sequenced from three isolates of F. effusum. The obtained sequences showed 95% nucleic acid and 100% amino acid homology (201–266 amino acids on exon 5 of the cytochrome b gene) with Venturia inaequalis (NCBI GenBank accession number AF047029). And in the maximum parsimony tree based on nucleotide sequences, F. effusum and V. inaequalis were clustered, with a 92% bootstrap value. The taxonomic classification of the pecan scab fungus was supported based on the cytochrome b region.
KeywordsVenturia anamorph Carya Sequence analyses
We acknowledge Bonnie Evans for technical assistance, and Sidney Law and Tim Varnadore for assistance in locating orchards. Financial support provided by E. I. Du Pont de Nemours and Company, Inc., United Phosphorus Inc., and the Georgia Agricultural Commodity Commission for Pecans is also appreciated.
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