Variation in the ribosomal ITS-sequence of the lichens Buellia frigida and Xanthoria elegans from the Vestfold Hills, eastern Antarctica

Abstract

Abstract:Thalli of the lichens Buellia frigida and Xanthoria elegans were collected from five different locations each 5–15km apart in the Vestfold Hills, Princess Elizabeth Land, eastern Antarctica. A further collection was made from Mawson Station, Mac Robertson Land, eastern Antarctica, 660km away. DNA was extracted from whole thalli and the ribosomal ITS region amplified by PCR using fungal specific primers. Resulting products were sequenced to gain an indication of whether or not variation was present within populations of lichen-forming fungi from continental Antarctica, and therefore of the availability of genetic resources to react to pressures such as climate change. Three genotypes ofB. frigida and two of X. elegans were detected in the Vestfold Hill collections. However, these differed by only one nucleotide position suggesting the presence of relatively little genetic variation, if the ITS region is indicative of the overall genome. Buellia frigida collected from Mawson Station had an identical ITS region sequence to the most common Vestfold Hills genotype, indicating that this species may have a low level of genetic variation across much of eastern Antarctica. In contrast, X. elegans collected from Mawson showed considerable genetic variation from the Vestfolds thalli, differing at 14·2% of nucleotide positions and had an identical ITS region sequence to an isolate from maritime Antarctica 4960km away. Samples from the Vestfold Hills formed a distinct cluster in a phylogenetic analysis of ITS sequences from a worldwide collection of X. elegans isolates.