基于 SSR 标记分析毛白杨天然 2n 配子的遗传组成和传递的亲本杂合度。
Analysis of genetic composition and transmitted parental heterozygosity of natural 2n gametes in Populus tomentosa based on SSR markers.
机构信息
Beijing Advanced Innovation Center for Tree Breeding by Molecular Design, Beijing Forestry University, Beijing, 100083, China.
National Engineering Laboratory for Tree Breeding, Beijing Forestry University, Beijing, 100083, China.
出版信息
Planta. 2018 Jun;247(6):1407-1421. doi: 10.1007/s00425-018-2871-4. Epub 2018 Mar 9.
Natural 2n female gametes and transmission of parental heterozygosity by natural 2n gametes in Populus tomentosa are reported for the first time, which provides a new approach to polyploid breeding. Naturally occurring 2n pollen is widespread in Populus tomentosa and plays an important role in polyploid breeding. However, the competitiveness of 2n pollen is lower than that of haploid pollen during pollination and fertilization, so 2n pollen is less efficient at fertilizing haploid female gametes to produce polyploids. In theory, polyploids can also be obtained when 2n female gametes are fertilized by haploid pollen. Thus, the question becomes whether natural 2n female gametes exist in P. tomentosa, which can be answered by examining the genetic composition of natural 2n gametes. In this study, the origin of 87 triploids from the hybrid combination "X-2 × Z-5" was identified by SSR markers and 21% of natural 2n gametes were found to originate from female parents. Four SSR loci with low recombination rates were used to identify the genetic composition of natural 2n gametes. The results showed that the genetic composition of 2n female gametes was mainly characterized by SDR, while 2n male gametes were mainly produced by FDR. Moreover, the transmission of parental heterozygosity by natural 2n gametes, which is significantly different between female and male parents in FDR and SDR types, was analysed using 42 SSR primers. Here, we report naturally occurring 2n female gametes for the first time in P. tomentosa and reveal the genetic constitution and transmitted parental heterozygosity of these gametes. Our results provide a foundation for theoretical research into 2n gametes and their application in new polyploid breeding strategies.
首次报道了毛白杨中自然 2n 雌配子和自然 2n 配子传递亲本杂合性，这为多倍体育种提供了新途径。自然发生的 2n 花粉在毛白杨中广泛存在，在多倍体育种中发挥着重要作用。然而，在授粉和受精过程中，2n 花粉的竞争力低于单倍体花粉，因此 2n 花粉在使单倍体雌配子受精产生多倍体方面效率较低。从理论上讲，当 2n 雌配子被单倍体花粉受精时，也可以获得多倍体。因此，问题是毛白杨中是否存在自然 2n 雌配子，这可以通过检查自然 2n 配子的遗传组成来回答。在这项研究中，通过 SSR 标记鉴定了杂交组合“X-2 × Z-5”的 87 个三倍体的起源，发现 21%的自然 2n 配子来自母本。使用 4 个重组率低的 SSR 位点来鉴定自然 2n 配子的遗传组成。结果表明，2n 雌配子的遗传组成主要以 SDR 为主，而 2n 雄配子主要由 FDR 产生。此外，还利用 42 个 SSR 引物分析了自然 2n 配子传递亲本杂合性，在 FDR 和 SDR 类型中，自然 2n 配子传递亲本杂合性在母本和父本之间存在显著差异。在这里，我们首次报道了毛白杨中自然 2n 雌配子的存在，并揭示了这些配子的遗传组成和传递的亲本杂合性。我们的研究结果为 2n 配子的理论研究及其在新的多倍体育种策略中的应用提供了基础。
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