PDF(Pubmed)
Abstract：
The cytoplasm of Aegilops kotschyi is known for the induction of male sterility and haploidy in wheat. Both systems originally appeared rather simple, but manipulation of the standard chromosome constitution of the nuclear genome revealed additional interactions. This study shows that while there is little or no allelic variation at the main fertility restorer locus Rfmulti on chromosome arm 1BS, additional genes may also be involved in the nuclear-mitochondrial genome interactions, affecting not only male fertility but also the growth rate, from pollen competition for fertilization and early endosperm divisions all the way to seed size and plant maturity. Some of these effects appear to be of a sporophytic nature; others are gametophytic. Induction of parthenogenesis by a rye inducer in conjunction with the Ae. kotschyi cytoplasm is well known. However, here we show that the cytoplasmic-nuclear interactions affect all aspects of double fertilization: producing maternal haploids from unfertilized eggs, diploids from fertilized eggs or synergids, embryo-less kernels, and fertilized eggs without fertilization of the double nucleus in the embryo sack. It is unclear how frequent the inducers of parthenogenesis are, as variation, if any, is obscured by suppressors present in the wheat genome. Genetic dissection of a single wheat accession revealed five distinct loci affecting the rate of maternal haploid production: four acting as suppressors and one as an enhancer. Only when the suppressing haplotypes are confirmed may it be possible to the identify genetic variation of haploidy inducers, map their position(s), and determine their nature and the mode of action.
摘要：
Aegilopskotschyi的细胞质以诱导小麦的雄性不育和单倍体而闻名。这两个系统最初看起来相当简单，但是操纵核基因组的标准染色体构成揭示了额外的相互作用。这项研究表明，尽管染色体臂1BS上的主要育性恢复位点Rfmulti几乎没有等位基因变异，其他基因也可能参与核-线粒体基因组相互作用，不仅影响男性生育率，而且影响增长率，从花粉竞争受精和早期胚乳分裂一直到种子大小和植物成熟。这些作用中的一些似乎具有孢子体性质；其他是配子体。黑麦诱导剂与Ae结合诱导孤雌生殖。kotschyi细胞质是众所周知的。然而,在这里，我们表明细胞质-核相互作用影响双重受精的各个方面：从未受精卵产生母体单倍体，来自受精卵或协同体的二倍体，无胚胎内核，和受精卵，而胚袋中的双核没有受精。目前还不清楚孤雌生殖的诱导剂有多频繁，作为变异，如果有的话,被小麦基因组中存在的抑制剂掩盖。单个小麦的遗传解剖显示，有五个不同的基因座会影响母体单倍体的产生率：四个充当抑制剂，一个充当增强子。只有当抑制单倍型被证实时，才有可能识别单倍性诱导物的遗传变异。映射他们的位置，并确定它们的性质和行动方式。
