Characterisation of a β-tubulin gene from Melampsora lini and comparison of fungal β-tubulin genes

A Melampsora lini beta -tubulin gene and flanking sequence has been isolated and characterised. The gene contains 8 introns, is expressed in germinating urediospores and vegetative mycelia and encodes a 448 amino acid protein that is similar to other fungal beta -tubulin genes. Evidence for a second beta -tubulin gene within the M. lini genome is also presented. The predicted M. lini beta -tubulin protein was compared with 34 other fungal beta -tubulin proteins in a phylogenetic analysis and, in general, good agreement was observed between the derived beta -tubulin based phylogeny and the current taxonomic status of these species. However, it second beta -tubulin protein found in five fungal species is atypical when compared to other fungal beta -tubulin proteins. Analysis of in:ron positions within 33 fungal beta -tubulin genes showed that intron location was generally characteristic of the fungal class, with euascomycete fungi showing particularly striking conservation of intron position, although intron number was variable iind intron sequences showed little conservation.