Department of Biology, University of New Mexico, Albuquerque, NM 87131 USA.
Department of Biology, University of New Mexico, Albuquerque, NM 87131 USA.
Fungal Genet Biol. 2019 Jan;122:47-52. doi: 10.1016/j.fgb.2018.12.004. Epub 2018 Dec 14.
A survey of genomes reported here for 10 isolates of Monosporascus species and an additional 25 genomes from other members of the Xylariales (representing 15 genera) available in public databases indicated that genes typically associated with MAT1-1 (mat A) or MAT1-2 (mat a) mating types are absent or have diverged greatly relative to counterparts in other Pezizomycotina. This was particularly surprising for isolates known to be homothallic, given that homothallic members of the Pezizomycotina typically possess a MAT1-1-1 (mat A-1) gene and one or both of two other closely-linked mating-type genes, MAT1-1-2 (mat A-2) and MAT1-1-3 (mat A-3), in addition to MAT1-2-1 (mat a-1). We failed to detect candidate genes for either MAT1-1-1 or MAT1-1-2 in any member of the Xylariales. Genes related to MAT1-2-1 and MAT1-1-3 are present in the genomes examined, but most appear to be orthologs of MATA_HMG (high-mobility group) genes with non-mating-type functions rather than orthologs of mating-type genes. Several MATA_HMG genes were found in genome positions that suggest they are derived from mating-type genes, but these genes are highly divergent relative to known MAT1-2-1 and MAT1-1-3 genes. The genomes examined represent substantial diversity within the order and include M. cannonballus, M. ibericus, Xylaria hypoxylon, X. striata, Daldinia eschscholzii, Eutypa lata, Rosellinia necatrix, Microdochium bolleyi and several others. We employed a number of avenues to search for homologs, including multiple BLAST approaches and examination of annotated genes adjacent to genes known to flank mating regions in other members of the Ascomycota. The results suggest that the mating regions have been lost from, or altered dramatically in, the Xylariales genomes examined and that mating and sexual development in these fungi are controlled differently than has been reported for members of the Pezizomycotina studied to date.
这里报告的 10 株单囊壳菌物种的基因组调查和另外 25 株来自其他子囊菌门（代表 15 个属）的基因组在公共数据库中可用，表明通常与 MAT1-1（mat A）或 MAT1-2（mat a）交配型相关的基因缺失或与其他 Pezizomycotina 中的对应基因有很大差异。这对于已知为同宗交配的分离株来说尤其令人惊讶，因为 Pezizomycotina 的同宗交配成员通常具有 MAT1-1-1（mat A-1）基因和两个紧密连锁的交配型基因之一或两个，MAT1-1-2（mat A-2）和 MAT1-1-3（mat A-3），除了 MAT1-2-1（mat a-1）。我们未能在任何子囊菌门成员中检测到 MAT1-1-1 或 MAT1-1-2 的候选基因。与 MAT1-2-1 和 MAT1-1-3 相关的基因存在于检查的基因组中，但大多数似乎是具有非交配型功能的 MATA_HMG（高迁移率组）基因的同源物，而不是交配型基因的同源物。在基因组位置发现了几个 MATA_HMG 基因，表明它们源自交配型基因，但这些基因与已知的 MAT1-2-1 和 MAT1-1-3 基因高度分化。检查的基因组代表了该目中的很大多样性，包括 M. cannonballus、M. ibericus、Xylaria hypoxylon、X. striata、Daldinia eschscholzii、Eutypa lata、Rosellinia necatrix、Microdochium bolleyi 和其他几个。我们采用了多种途径来搜索同源物，包括多种 BLAST 方法和检查其他子囊菌门成员中已知侧翼交配区的邻近基因的注释。结果表明，交配区已经从检查的子囊菌门基因组中丢失或发生了巨大变化，这些真菌的交配和有性发育与迄今为止研究的 Pezizomycotina 成员报道的不同。
