Chengdu Academy of Agricultural and Forestry Sciences, Chengdu, 611130, China.
Chengdu Research Branch, National Rapeseed Genetic Improvement Center, Chengdu, 611130, China.
BMC Plant Biol. 2021 May 3;21(1):207. doi: 10.1186/s12870-021-02981-z.
Artificial synthesis of octoploid rapeseed double haploid (DH) induction lines Y3380 and Y3560 was made possible by interspecific hybridization and genome doubling techniques. Production of pure lines by DH induction provides a new way to achieve homozygosity earlier in B.napus. Previously, the mechanism of induction, and whether the induction has obvious maternal genotypic differences or not, are not known so far.
In this study, different karyogene and cytoplasmic genotype of B.napus were pollinated with the previously reported DH inducers e.g. Y3380 and Y3560. Our study presents a fine comparison of different cytoplasmic genotypes hybridization to unravel the mechanism of DH induction. Ploidy identification, fertility and SSR marker analysis of induced F generation, revealed that ploidy and phenotype of the induced F plants were consistent with that type of maternal, rather than paternal parent. The SNP chip analysis revealed that induction efficiency of DH inducers were affected by the karyogene when the maternal cytoplasmic genotypes were the same. However, DH induction efficiency was also affected by cytoplasmic genotype when the karyogenes were same, and the offspring of the ogura cytoplasm showed high frequency inducer gene hybridization or low-frequency infiltration.
The induction effect is influenced by the interaction between maternal karyogene and cytoplasmic genotype, and the results from the partial hybridization of progeny chromosomes indicate that the induction process may be attributed to the selective elimination of paternal chromosome. This study provides a basis for exploring the mechanism of DH inducer in B.napus, and provides new insights for utilization of inducers in molecular breeding.
通过种间杂交和基因组加倍技术，人工合成了八倍体油菜双单倍体（DH）诱导系 Y3380 和 Y3560。DH 诱导系产生的纯系为油菜更早实现纯合提供了新途径。此前，诱导的机制，以及诱导是否存在明显的母本基因型差异，目前还不得而知。
在这项研究中，用先前报道的 DH 诱导剂 Y3380 和 Y3560 对不同的油菜核型和细胞质基因型进行授粉。我们的研究对不同细胞质基因型的杂交进行了精细比较，以揭示 DH 诱导的机制。对诱导 F1 代的倍性鉴定、育性和 SSR 标记分析表明，诱导 F1 代的倍性和表型与母本类型一致，而不是与父本类型一致。SNP 芯片分析表明，当母本细胞质基因型相同时，DH 诱导剂的诱导效率受核型的影响。然而，当核型相同时，DH 诱导效率也受细胞质基因型的影响，并且 ogura 细胞质的后代表现出高频诱导基因杂交或低频渗入。
诱导效果受母本核型和细胞质基因型相互作用的影响，后代染色体部分杂交的结果表明，诱导过程可能归因于父本染色体的选择性消除。本研究为探索油菜 DH 诱导剂的作用机制提供了依据，为分子育种中诱导剂的利用提供了新的思路。
