Genome-wide recombination variation in biparental segregating and reciprocal backcross populations provides information for introgression breeding in Brassica napus
Genome-wide recombination variation in biparental segregating and reciprocal backcross populations provides information for introgression breeding in Brassica napus
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DOI：
10.1016/j.cj.2022.07.008
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发表时间：
2022-08
期刊：
影响因子：
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通讯作者：
M. Wang;G. King;Lei Shi;Ruiyuan Li;Y. Zhang;Xiaohua Wang;J. Meng;J. Tu;J. Zou
中科院分区：
文献类型：
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作者：
M. Wang;G. King;Lei Shi;Ruiyuan Li;Y. Zhang;Xiaohua Wang;J. Meng;J. Tu;J. Zou
植物基因组重组模式的变化为物种进化、遗传多样性和作物改良提供了信息。研究了油菜（Brassica napus） （AACC, 2n= 38）异源多倍体基因组双亲本分离和反向回交群体中产生的减数分裂杂交。从中国和欧洲菜籽两个纯合子组合的亲本中获得1445个杂交系，以提高QTL分辨率，实现基因组互渗。利用6161个遗传箱和固定着丝粒区域构建的高密度遗传图谱，确定每条染色体的重组变异模式。大约93%的基因组包含杂交，平均速率为3.8 cM Mb−1，其余7%归因于着丝粒或低标记密度。重组热点在A基因组中占主导地位，其中包括三分之二与育种渐渗有关的热点。拉伯。遗传背景可能影响重组变异。欧洲冬季油菜遗传多样性向中国半冬季油菜遗传多样性的渗透表现出半冬季环境下杂交率的增加。在历史上，较高的重组率有助于选择性性状的改善，证据包括在A10染色体的热点上积累有利于种子含油量的等位基因。相反，强的人工选择可能会影响重组率的变化，就像A09上硫代葡萄糖苷等位基因强选择导致的冷斑一样。但谱系分析表明，通过杂交设计，寒冷区域将迅速被激活。了解22个性状的QTL相关重组热点和冷点，可以指导两个基因库间渐渗育种的选择策略。这些结果和丰富的基因组资源拓宽了我们对异源多倍体重组行为的认识，并可能促进油菜的遗传改良。
Variation in patterns of recombination in plant genomes provides information about species evolution, genetic diversity and crop improvement. We investigated meiotic crossovers generated in biparental segregating and reciprocal backcross populations of the allopolyploid genome of rapeseed (Brassica napus) (AACC, 2n= 38). A structured set of 1445 intercrossed lines was derived from two homozygousde novogenome-assembled parents that represented the major genetic clusters of semi-winter Chinese and winter European rapeseeds, and was used to increase QTL resolution and achieve genomic reciprocal introgression. A high-density genetic map constructed with 6161 genetic bins and anchored centromere regions was used to establish the pattern of recombination variation in each chromosome. Around 93% of the genome contained crossovers at a mean rate of 3.8 cM Mb−1, with the remaining 7% attributed to centromeres or low marker density. Recombination hotspots predominated in the A genome, including two-thirds of those associated with breeding introgression fromB. rapa. Genetic background might affect recombination variation. Introgression of genetic diversity from European winter to Chinese semi-winter rapeseed showed an increase in crossover rate under the semi-winter environment. Evidence for an elevated recombination rate having historically contributed to selective trait improvement includes accumulation of favorable alleles for seed oil content on hotspots of chromosome A10. Conversely, strong artificial selection may affect recombination rate variation, as appears to be the case with a coldspot resulting from strong selection for glucosinolate alleles on A09. But the cold region would be promptly reactivated by crossing design indicated by the pedigree analysis. Knowledge of recombination hotspots and coldspots associated with QTL for 22 traits can guide selection strategies for introgression breeding between the two gene pools. These results and rich genomic resources broaden our understanding of recombination behavior in allopolyploids and may advance rapeseed genetic improvement.