Methods Strains, growth conditions, and DNA extraction Seventy six strains of Beauveria bassiana, 3 of B. brongniartii and 14 strains of 9 other Beauveria species, together with one representative from each of 11 species belonging to the order Hypocreales were examined and are listed in Additional File 2, Table S2 (a fungal collection kept in the Department of Genetics and Biotechnology, Athens University, Greece). All fungal isolates were derived from single conidial spores grown on Potato
Dextrose Agar (PDA) plates and all cultures were started from single spore isolations. Liquid cultures were in 250 ml flasks containing 50 ml of medium, inoculated with a spore suspension to reach 105/ml final spore concentration, on an orbital shaker at 150 rev min-1, 25°C, for 3-4 days. Mycelia were removed by vacuum filtration, lyophilized for 2-4 days, and ground in liquid nitrogen using MK-8931 datasheet a mortar and pestle. Small quantities selleckchem of ground
mycelia (50-100 mg) were used for the extraction of DNA as described [69]. Construction of libraries, PCR amplification and sequencing of the complete mt genomes Isolation and digestion of nuclear and mtDNA from B. bassiana strain Bb147 and B. brongiartii strain IMBST 95031 were performed as previously described [69]. EcoRI and HindIII restricted fragments of CsCl-purified mtDNA were ligated into vector pBluescript KS+ (Stratagene, Cedar Creek, TX), analysed, subcloned and sequenced, thus covering BCKDHA over 78-80% of their complete mtDNA. The rest of the mtDNA and overlapping junctions were determined through sequence analysis of long-expand PCR amplicons. For this purpose, previously designed primers were used as follows: nad1B, cox3B, atp6A [42],
cox2R, LSUER [27], LSUSF [38], and NMS1, NMS2 [70]. The primer pairs and respective amplicon sizes are shown in Additional File 7 (Additional File 7, Table S7). No sequence differences were observed between cloned fragments and PCR amplicons for the overlapping regions. PCR amplifications were performed with the proof-reading polymerase Herculase (Stratagene), in a PTC-200 Gradient Peltier Thermal Cycler (MJ Research, Waltham, MA), according to the manufacturer’s CP673451 molecular weight instructions. PCR products were cloned in vector pDrive (QIAGEN, Hilden, Germany), subcloned as smaller fragments to pBluescript SKII and sequenced. Sequencing was performed with the Thermo Sequenase Primer Cycle Sequencing kit (Amersham Biosciences, Amersham, UK), and the reactions were analyzed at a LICOR 4200 IR2 automated sequencer. All fragments were sequenced in both directions. DNA similarity searches were performed with Basic Local Alignment Search Tool (BLAST 2.2.14) [71]. The tRNAs were predicted by tRNAscan-SE 1.21 [72]. Intron identification and characterization utilized the intron prediction tool RNAweasel [73]. Phylogenetic analysis The ITS1-5.