Maize Research Institute, Sichuan Agricultural University, Chengdu, 611130, China.
Sericulture Research Institute, Sichuan Academy of Agricultural Sciences, Nanchong, 637000, China.
Theor Appl Genet. 2024 Jan 22;137(1):28. doi: 10.1007/s00122-023-04540-6.
We developed an array of Zea-Tripsacum tri-hybrid allopolyploids with multiple ploidies. We unveiled that changes in genome dosage due to the chromosomes pyramiding and shuffling of three species effects karyotypic heterogeneity, reproductive diversity, and phenotypic variation in Zea-Tripsacum allopolyploids. Polyploidy, or whole genome duplication, has played a major role in evolution and speciation. The genomic consequences of polyploidy have been extensively studied in many plants; however, the extent of chromosomal variation, genome dosage, phenotypic diversity, and heterosis in allopolyploids derived from multiple species remains largely unknown. To address this question, we synthesized an allohexaploid involving Zea mays, Tripsacum dactyloides, and Z. perennis by chromosomal pyramiding. Subsequently, an allooctoploid and an allopentaploid were obtained by hybridization of the allohexaploid with Z. perennis. Moreover, we constructed three populations with different ploidy by chromosomal shuffling (allopentaploid × Z. perennis, allohexaploid × Z. perennis, and allooctoploid × Z. perennis). We have observed 3 types of sexual reproductive modes and 2 types of asexual reproduction modes in the tri-species hybrids, including 2n gamete fusion (2n + n), haploid gamete fusion (n + n), polyspermy fertilization (n + n + n) or 2n gamete fusion (n + 2n), haploid gametophyte apomixis, and asexual reproduction. The tri-hybrids library presents extremely rich karyotype heterogeneity. Chromosomal compensation appears to exist between maize and Z. perennis. A rise in the ploidy of the trihybrids was linked to a higher frequency of chromosomal translocation. Variation in the degree of phenotypic diversity observed in different segregating populations suggested that genome dosage effects phenotypic manifestation. These findings not only broaden our understanding of the mechanisms of polyploid formation and reproductive diversity but also provide a novel insight into genome pyramiding and shuffling driven genome dosage effects and phenotypic diversity.
我们开发了一系列具有多种倍性的玉米-摩擦禾三体系杂种异源多倍体。我们揭示了由于三个物种的染色体堆积和洗牌导致的基因组剂量变化会影响玉米-摩擦禾异源多倍体的核型异质性、生殖多样性和表型变异。多倍体或全基因组加倍在进化和物种形成中发挥了重要作用。多倍体的基因组后果在许多植物中得到了广泛研究；然而，来自多个物种的异源多倍体的染色体变异、基因组剂量、表型多样性和杂种优势的程度在很大程度上仍然未知。为了解决这个问题，我们通过染色体堆积合成了一个涉及玉米、摩擦禾和多年生摩擦禾的异源六倍体。随后，通过异源六倍体与多年生摩擦禾的杂交获得了一个异源八倍体和一个异源五倍体。此外，我们通过染色体洗牌构建了三个不同倍性的群体（异源五倍体×多年生摩擦禾、异源六倍体×多年生摩擦禾和异源八倍体×多年生摩擦禾）。我们在三物种杂种中观察到 3 种有性生殖模式和 2 种无性繁殖模式，包括 2n 配子融合（2n+n）、单倍体配子融合（n+n）、多精受精（n+n+n）或 2n 配子融合（n+2n）、单倍体配子无融合生殖和无性繁殖。三杂种文库呈现出极其丰富的核型异质性。玉米和多年生摩擦禾之间似乎存在染色体补偿。三杂种的倍性升高与染色体易位的频率升高有关。不同分离群体中观察到的表型多样性程度的变化表明，基因组剂量效应表型表现。这些发现不仅拓宽了我们对多倍体形成和生殖多样性机制的理解，还为基因组堆积和洗牌驱动的基因组剂量效应和表型多样性提供了新的认识。
