Department of Biology, Saint Louis University, St. Louis, MO 63101-2010, USA.
Fungal Genet Biol. 2012 Jan;49(1):2-14. doi: 10.1016/j.fgb.2011.11.008. Epub 2011 Dec 6.
The mitochondrial (mt) genomes of Fusarium verticillioides, Fusarium solani and Fusarium graminearum were annotated and found to be 53.7, 63.0 and 95.7 kb in length, respectively. The genomes encode all genes typically associated with mtDNAs of filamentous fungi yet are considerably larger than the mt genome of F. oxysporum. Size differences are largely due to the number of group I introns. Surprisingly, the genomes contain a highly variable region of 7-9 kb that encodes an exceptionally large, unidentified open reading frame (uORF). The region has the hallmarks of a horizontally transmitted DNA and was likely acquired prior to the divergence of Fusarium species. Two additional uORFs were detected that are also under positive selection. DNA repeats associated with the uORFs suggest that 3' gene duplication may be an adaptive mechanism to modify coding regions or generate new ORFs. The acquisition of these new genes contrasts to the wide-scale size reduction experienced by fungal mt genomes.
镰刀菌属（Fusarium）的丝状真菌线粒体（mt）基因组被注释，发现其长度分别为 53.7、63.0 和 95.7kb。基因组编码所有与丝状真菌 mtDNA 相关的基因，但明显大于尖孢镰刀菌（F. oxysporum）的 mt 基因组。大小差异主要归因于 I 组内含子的数量。令人惊讶的是，基因组包含一个 7-9kb 的高度可变区，该区域编码一个异常大的、未识别的开放阅读框（uORF）。该区域具有水平传播 DNA 的特征，可能是在镰刀菌属物种分化之前获得的。还检测到另外两个受正选择影响的 uORF。与 uORF 相关的 DNA 重复序列表明，3' 基因重复可能是一种适应性机制，可以修饰编码区或产生新的 ORF。这些新基因的获得与真菌 mt 基因组经历的大规模大小减少形成鲜明对比。
