Faculty of Agriculture, Kindai University, Nara, 631-8505, Japan.
Center for Ecological Research, Kyoto University, Hirano 2-509-3, Otsu, 520-2113, Japan.
Planta. 2024 Aug 13;260(3):71. doi: 10.1007/s00425-024-04497-w.
Using octoploid somatic hybrids with excessive C genome sets, AABBCCCC, a diverse allohexaploid, AABBCC, was produced by C genome reduction through subsequent crossing with various AABB cultivars. Even when somatic hybrids are produced, the plants that are produced are rarely in themselves an innovative crop. In this study, we used somatic hybrids of Brassica juncea (AABB) and B. oleracea (CC) as model cases for the genetic diversification of the somatic hybrids. One cell of 'Akaoba Takana' (B. juncea) and two cells of 'Snow Crown' (B. oleracea) were fused to create several somatic hybrids with excessive C genomes, AABBCCCC. Using AABBCCCC somatic hybrids as mother plants and crossing with 'Akaoba Takana', the AABBCC progenies were generated. When these AABBCC plants were self-fertilized, and flow cytometric (FCM) analysis was performed on the next generations, differences in the relative amount of genome size variation were observed, depending on the different AABBCCCC parents used for AABBCC creation. Further self-progeny was obtained for AABBCC plants with a theoretical allohexaploid DNA index by FCM. However, as the DNA indices of the progeny populations varied between plants used and aneuploid individuals still occurred in the progeny populations, it was difficult to say that the allohexaploid genome was fully stabilized. Next, to obtain genetic diversification of the allohexaploid, different cultivars of B. juncea were crossed with AABBCCCC, resulting in diverse AABBCC plants. Genetic diversity can be further expanded by crossbreeding plants with different AABBCC genome sets. Although genetic stability is necessary to ensure in the later generations, the results obtained in this study show that the use of somatic hybrids with excess genomes is an effective strategy for creating innovative crops.
利用具有过多 C 基因组的八倍体体细胞杂种 AABBCCCC，通过随后与各种 AABB 品种的杂交，通过 C 基因组减少产生了不同的异源六倍体 AABBCC。即使产生了体细胞杂种，所产生的植物本身也很少是创新作物。在这项研究中，我们使用了 Brassica juncea（AABB）和 B.oleracea（CC）的体细胞杂种作为体细胞杂种遗传多样化的模型案例。'Akaoba Takana'（B.juncea）的一个细胞和 'Snow Crown'（B.oleracea）的两个细胞融合，产生了几个具有过多 C 基因组的体细胞杂种 AABBCCCC。利用 AABBCCCC 体细胞杂种作为母本植物，并与 'Akaoba Takana'杂交，产生了 AABBCC 后代。当这些 AABBCC 植物自交，并对下一代进行流式细胞术（FCM）分析时，观察到根据用于创建 AABBCC 的不同 AABBCCCC 亲本，基因组大小变异的相对量存在差异。通过 FCM 对具有理论异源六倍体 DNA 指数的 AABBCC 植物进行了进一步的自交后代获得。然而，由于所用植物的后代群体的 DNA 指数不同，并且后代群体中仍然存在非整倍体个体，因此很难说异源六倍体基因组完全稳定。接下来，为了获得异源六倍体的遗传多样性，用不同的 B.juncea 品种与 AABBCCCC 杂交，产生了不同的 AABBCC 植物。通过杂交具有不同 AABBCC 基因组的植物，可以进一步扩大遗传多样性。尽管在后代中需要保证遗传稳定性，但本研究的结果表明，利用具有过多基因组的体细胞杂种是创造创新作物的有效策略。
