Different genome-specific chromosome stabilities in synthetic Brassica allohexaploids revealed by wide crosses with Orychophragmus
Different genome-specific chromosome stabilities in synthetic Brassica allohexaploids revealed by wide crosses with Orychophragmus
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DOI：
10.1093/aob/mcp099
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发表时间：
2009-07-01
期刊：
影响因子：
4.2
通讯作者：
Li, Zai-Yun
中科院分区：
文献类型：
--
作者：
Ge, Xian-Hong;Wang, Jing;Li, Zai-Yun
在栽培的芸薹属物种与另一种十字花科植物诸葛菜（2n = 24）的有性杂交中，有丝分裂和减数分裂期间亲本基因组的分离受遗传控制，但这种现象因芸薹属物种而异。为了进一步研究亲本基因组分离所涉及的机制，获得了来自三个来源的合成芸薹属异源六倍体（2n = 54，AABBCC）与诸葛菜的复合杂种并对其进行了表征。利用基因组原位杂交、扩增片段长度多态性（AFLP）和单链构象多态性（SSCP）来探究复合杂种及其后代的染色体/基因组成分以及rRNA基因表达。具有不同育性的复合杂种表现出不同于雌性异源六倍体的表型，并表达了诸葛菜的一些性状。这些杂种是混倍体（2n = 34 - 46），保留了异源六倍体的部分染色体组，包括A和B基因组的完整染色体以及一些C基因组染色体，但没有完整的诸葛菜染色体；检测到了诸葛菜特有的、双亲没有的以及六倍体中不存在的AFLP条带。复合杂种产生的后代其染色体/基因组成分偏向芥菜型油菜（2n = 36，AABB）以及具有两个不同起源基因组的新型芥菜型油菜品系。在所有异源六倍体和复合杂种中都检测到了黑芥的rRNA基因表达，这表明芸薹属异源四倍体中核仁显性的等级（黑芥，BB > 白菜型油菜，AA > 甘蓝型油菜，CC）在这些植物中仍然有效。在与诸葛菜杂交诱导外来染色体消除的过程中，这些合成的芸薹属异源六倍体的三个基因组的染色体表现出不同的基因组特异性稳定性（B > A > C），这可能受到核仁显性的影响。
In sexual hybrids between cultivated Brassica species and another crucifer, Orychophragmus violaceus (2n = 24), parental genome separation during mitosis and meiosis is under genetic control but this phenomenon varies depending upon the Brassica species. To further investigate the mechanisms involved in parental genome separation, complex hybrids between synthetic Brassica allohexaploids (2n = 54, AABBCC) from three sources and O. violaceus were obtained and characterized.Genomic in situ hybridization, amplified fragment length polymorphism (AFLP) and single-strand conformation polymorphism (SSCP) were used to explore chromosomal/genomic components and rRNA gene expression of the complex hybrids and their progenies.Complex hybrids with variable fertility exhibited phenotypes that were different from the female allohexaploids and expressed some traits from O. violaceus. These hybrids were mixoploids (2n = 34-46) and retained partial complements of allohexaploids, including whole chromosomes of the A and B genomes and some of the C genome but no intact O. violaceus chromosomes; AFLP bands specific for O. violaceus, novel for two parents and absent in hexaploids were detected. The complex hybrids produced progenies with chromosomes/genomic complements biased to B. juncea (2n = 36, AABB) and novel B. juncea lines with two genomes of different origins. The expression of rRNA genes from B. nigra was revealed in all allohexaploids and complex hybrids, showing that the hierarchy of nucleolar dominance (B. nigra, BB > B. rapa, AA > B. oleracea, CC) in Brassica allotetraploids was still valid in these plants.The chromosomes of three genomes in these synthetic Brassica allohexaploids showed different genome-specific stabilities (B > A > C) under induction of alien chromosome elimination in crosses with O. violaceus, which was possibly affected by nucleolar dominance.