Triticeae Research Institute, Chengdu Campus, Sichuan Agricultural University, Chengdu 611130, China.
Division of Plant Sciences, Research School of Biology, The Australian National University, Canberra 2601, Australia.
Genes (Basel). 2024 Jun 28;15(7):855. doi: 10.3390/genes15070855.
The cytoplasm of 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 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 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.
细胞质是诱导小麦雄性不育和单倍体的原因。这两个系统最初看起来相当简单，但对核基因组标准染色体组成的操纵揭示了额外的相互作用。本研究表明，虽然在 1BS 染色体臂上的主要育性恢复基因座 几乎没有或没有等位基因变异，但其他基因也可能参与核-线粒体基因组相互作用，不仅影响雄性育性，还影响生长速度，从花粉竞争受精和早期胚乳分裂到种子大小和植物成熟。这些影响中的一些似乎具有孢子体性质；其他是配子体。众所周知，黑麦诱导剂与 细胞质一起诱导孤雌生殖。然而，在这里我们表明，细胞质-核相互作用影响双受精的各个方面：从不受精的卵子产生母本单倍体，从受精的卵子或助细胞产生二倍体，无胚核，以及在胚囊中双核未受精的受精卵子。孤雌生殖诱导子的频率尚不清楚，因为小麦基因组中存在的抑制子掩盖了任何变异。对单个小麦品系的遗传剖析揭示了五个影响母本单倍体产生率的不同基因座：四个作为抑制子，一个作为增强子。只有当确认抑制性单倍型时，才有可能识别单倍体诱导子的遗传变异，定位它们的位置，并确定它们的性质和作用模式。
