Genetic variability of Ganoderma zonatum infecting palms in Florida

Ganoderma zonatum is a lethal pathogen of palms (Arecaceae) in Florida (USA) because it degrades the wood of the lowest section of the palm trunk. This fungus is widespread throughout Florida, where it has been observed on over 60 species of palms. The authors examined the genetic variability of 25 isolates of G. zonatum obtained in Florida from 12 different palm species and representing 17 unique property locations in eight counties to determine if G. zonatum represents a species complex. The three genomic regions examined were the nuc rDNA ITS1-5.8S-ITS2 region (ITS), the coding region for RNA polymerase II subunit 2 (rpb2) domains 6 and 7, and the partial gene for translation elongation factor 1α (tef1α). The results indicated that variability among these three genomic regions was minimal, and the variability observed was not related to palm host or geographic region within Florida. Thus, in the geographic region surveyed, G. zonatum does not appear to represent a species complex.