Isolation and Characterization of Novel BTB Domain Protein Encoding Genes from Fungal Grass Endophytes

Isolation and Characterization of Novel BTB Domain Protein Encoding Genes from Fungal Grass Endophytes

Pasture grasses belonging to the Pooideae sub-family of the Poaceae family frequently host symbiotic fungal endophytes. These include the sexual Epichloë species and the anamorphic asexual Neotyphodium species, which are thought to have evolved from Epichloë species either by the direct loss of sexual reproduction or by interspecific hybridisation. The two key temperate pasture grasses, tall fescue (Festuca arundinacea Schreb) and perennial ryegrass (Lolium perenne L.) interact with the fungal endophytes N. coenophialum and N. lolii, respectively. Large insert genomic DNA libraries are valuable resources for the discovery and isolation of genes and their regulatory sequences, for physical mapping, map-based cloning of target genes as well as for whole genome sequencing. BTB (Bric-a-brac, tram-track, broad complex) domains are highly conserved motifs of 120 amino acids in length. The domains are rich in hydrophobic amino acids, and mediate protein-protein interaction that lead to homomeric dimerisation and in some cases heteromeric dimerisation of a large number of functionally diverse proteins. The presence of BTB domains defines a large family of genes involved in various biological processes, such as the regulation of transcription, DNA binding activity and structural organisation of macromolecular structures. Genes encoding BTB domain proteins (BDP) have previously been described in viruses, yeasts, plants, nematodes, insects, fish and mammals. However, BDP genes have not as yet been described for filamentous fungi.