Hybrids between Brassica napus and B. nigra show frequent pairing between the B and A/C genomes and resistance to blackleg
Hybrids between Brassica napus and B. nigra show frequent pairing between the B and A/C genomes and resistance to blackleg
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DOI：
10.1007/s10577-019-09612-2
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发表时间：
2019-09-01
影响因子：
2.6
通讯作者：
Mason, Annaliese S.
中科院分区：
文献类型：
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作者：
Gaebelein, Roman;Alnajar, Dima;Mason, Annaliese S.
芸苔属杂种中高频率的同源重组甚至非同源染色体重组可以在基因组之间转移有用的性状，但也会使人工合成的异源多倍体不稳定。我们从杂交B中产生了三倍体杂种（2n = 3x = ABC）。napus（rapeseed，2n = 4x = AACC）× B.黑芥（black mustard，2n = 2x = BB）和三倍体染色体加倍的异源六倍体杂种（2n = 6x = AABBCC = 54）。这些杂种表现出对黑胫病（致病因子：斑点细球腔菌）的抗性，遗传自它们的B。黑人家长为了评估这种抗性在B基因组和B的A和C亚基因组之间转移的可能性。napus，以及评估来自杂交B的异源六倍体的基因组稳定性。napus × B. nigra，使用经典的细胞遗传学和基因组原位杂交来评估这些杂种中的非同源染色体配对的频率。减数分裂是非常不规则的，和非同源染色体配对之间的B基因组和A/C基因组是常见的三倍体杂交（观察到38%的花粉母细胞）和异源六倍体杂交（观察到15%的花粉母细胞）。我们的研究结果表明，黑胫病抗性从B基因组渐渗到A或C基因组中应该是可能的，但是来自这种基因组组合的异源六倍体可能是不稳定的。
High frequencies of homoeologous and even non-homologous chromosome recombination in Brassica hybrids can transfer useful traits between genomes, but also destabilise synthetic allopolyploids. We produced triploid hybrids (2n = 3x = ABC) from the cross B. napus (rapeseed, 2n = 4x = AACC) x B. nigra (black mustard, 2n = 2x = BB) by embryo rescue and allohexaploid hybrids (2n = 6x = AABBCC = 54) by chromosome doubling of the triploids. These hybrids demonstrated resistance to blackleg disease (causal agent: Leptosphaeria maculans) inherited from their B. nigra parent. In order to assess the possibility of transfer of this resistance between the B genome and the A and C subgenomes of B. napus, as well as to assess the genomic stability of allohexaploids from the cross B. napus x B. nigra, frequencies of non-homologous chromosome pairing in these hybrids were assessed using classical cytogenetics and genomic in-situ hybridization. Meiosis was highly irregular, and non-homologous chromosome pairing between the B genome and the A/C genomes was common in both triploid hybrids (observed in 38% of pollen mother cells) and allohexaploid hybrids (observed in 15% of pollen mother cells). Our results suggest that introgression of blackleg resistance from the B genome into the A or C genomes should be possible, but that allohexaploids from this genome combination are likely unstable.