Department of Genetics and Applied Microbiology, University of Debrecen, Debrecen, Hungary.
Department of Biotechnology, Institute of Microbiology and Microbial Biotechnology, University of Natural Resources and Life Sciences Vienna (BOKU), Muthgasse 18, 1190, Vienna, Austria.
Sci Rep. 2023 Jan 20;13(1):1112. doi: 10.1038/s41598-023-27693-2.
Combination of the genomes of Saccharomyces species has great potential for the construction of new industrial strains as well as for the study of the process of speciation. However, these species are reproductively isolated by a double sterility barrier. The first barrier is mainly due to the failure of the chromosomes to pair in allodiploid meiosis. The second barrier ensures that the hybrid remains sterile even after genome duplication, an event that can restore fertility in plant interspecies hybrids. The latter is attributable to the autodiploidisation of the allotetraploid meiosis that results in sterile allodiploid spores (return to the first barrier). Occasionally, mating-competent alloaneuploid spores arise by malsegregation of MAT-carrying chromosomes. These can mate with cells of a third species resulting in aneuploid zygotes having at least one incomplete subgenome. Here we report on the construction of euploid three-species hybrids by making use of "rare mating" between a sterile S. kudriavzevii x S. uvarum allodiploid hybrid and a diploid S. cerevisiae strain. The hybrids have allotetraploid 2nn n genomes consisting of complete sets of parental chromosomes. This is the first report on the production of euploid three-species Saccharomyces hybrids by natural mating, without genetic manipulation. The hybrids provide possibilities for studying the interactions of three allospecific genomes and their orthologous genes present in the same cell.
酿酒酵母属物种基因组的组合对于构建新型工业菌株以及研究物种形成过程具有巨大潜力。然而，这些物种通过双重不育屏障进行有性生殖隔离。第一个障碍主要是由于在异源二倍体减数分裂中染色体配对失败。第二个障碍确保杂种即使在基因组复制后仍然保持不育，而这种事件可以恢复植物种间杂种的育性。后者归因于异源四倍体减数分裂的同源单倍体化，导致不育的异源二倍体孢子（回到第一个障碍）。偶尔，由携带 MAT 的染色体错分导致具有交配能力的异源三体孢子的产生。这些孢子可以与第三个物种的细胞交配，产生至少一个不完全亚基因组的非整倍体合子。在这里，我们通过利用不育的 S. kudriavzevii x S. uvarum 异源二倍体杂种与二倍体 S. cerevisiae 菌株之间的“稀有交配”来构建同源三体杂种。杂种具有全基因组的异源四倍体 2nn n 基因组，由完整的亲本染色体组组成。这是首次通过自然交配而无需遗传操作生产同源三体酿酒酵母杂种的报道。杂种为研究三个异源基因组及其在同一细胞中存在的直系同源基因的相互作用提供了可能性。
