Phylogenetic relationships between members of the crucifer pathogenic Leptosphaeria maculans species complex as shown by mating type (MAT1-2), actin, and β-tubulin sequences
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- 作者：Kerstin Voigt ; Anton J. Cozijnsen ; Jü ; rgen Kroymann ; Stefanie Pö ; ggeler and Barbara J. Howlett
- 关键词：Mating type ; Leptosphaeria maculans ; Phylogeny ; Pleosporales ; uORFs ; Sliding window analyses
- 刊名：Molecular Phylogenetics and Evolution
- 出版年：2005
- 出版时间：November 2005
- 年：2005
- 卷：37
- 期：2
- 页码：541-557
- 全文大小：663 K
文摘
The dothideomycetous fungus Leptosphaeria maculans comprises a complex of species differing in specificity and pathogenicity on Brassica napus. Twenty-eight isolates were investigated and compared to 20 other species of the Pleosporales order. Sequences of the mating type MAT1-2 (23), fragments of actin (48) and β-tubulin (45) genes were determined and used for phylogenetic analyses inferred by maximum parsimony, distance, maximum likelihood, and Bayesian approaches. These different approaches using single genes essentially confirmed findings using concatanated sequences. L. maculans formed a monophyletic group separate from Leptosphaeria biglobosa. The L. biglobosa clade encompasses five sub-clades; this finding is consistent with classification made previously on the basis of internal-transcribed sequences of the ribosomal DNA repeat. The propensity for purifying and neutral evolution of the three genes was determined using sliding window analysis, a technique not previously applied to genes of filamentous fungi. For members of the L. maculans species complex, this approach showed that in comparison to actin and β-tubulin, exonic sequences of MAT1-2 were more diverse and appeared to evolve at a faster rate. However, different regions of MAT1-2 displayed different degrees of sequence conservation. The more conserved upstream region (including the High Mobility Group domain) may be better suited for interspecies differentiation, while the more diverse downstream region is more appropriate for intraspecies comparisons.