Zhu Bin, Tu Yuqin, Zeng Pan, Ge Xianhong, Li Zaiyun
National Key Lab of Crop Genetic Improvement, National Center of Oil Crop Improvement, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan 430070, People's Republic of China.
Crop Research Institute, Jiangxi Academy of Agricultural Sciences, Nanchang 330200, People's Republic of China.
Genetics. 2016 Nov;204(3):1015-1027. doi: 10.1534/genetics.116.190967. Epub 2016 Sep 16.
As the dynamic nature of progenitor genomes accompanies the speciation by interspecific hybridization, the extraction of the constituent subgenome(s) from a natural allopolyploid species of long history and then restitution of the progenitor(s) provides the unique opportunity to study the genome evolution and interplay. Herein, the A subgenome from the allotetraploid oilseed rape (Brassica napus L., AACC) was extracted through inducing the preferential elimination of C-subgenome chromosomes in intertribal crosses and the progenitor B. rapa was restituted (RBR). Then by crossing and backcrossing RBR with B. napus donor, the C subgenome was in situ dissected by adding each of its nine chromosomes to the extracted A subgenome and establishing the whole set of monosonic alien addition lines (MAALs). RBR from spring-type B. napus genotype "Oro" expressed a phenotype resembling some type of B. rapa never observed before, but showed a winter-type flowering habit. This RBR had weaker growth vigor and suffered more seriously from biotic and abiotic stresses compared with Oro. The phenotypes specific for these MAALs showed the location of the related genes on the particular C-subgenome chromosomes. These MAALs exhibited obviously different frequencies in homeologous pairing and transmission of additional C-subgenome chromosomes, which were associated with the distinct degrees of their relatedness, and even with the possible genetic regulation for meiotic pairing evolved in B. napus Finally, large scaffolds undetermined for sequence assembly of B. napus were anchored to specific C-subgenome chromosomes using MAALs.
由于祖先基因组的动态性质伴随着种间杂交导致的物种形成，从历史悠久的天然异源多倍体物种中提取组成亚基因组，然后恢复祖先基因组，为研究基因组进化和相互作用提供了独特的机会。在此，通过诱导族间杂交中C亚基因组染色体的优先消除，从异源四倍体油菜（甘蓝型油菜，AACC）中提取了A亚基因组，并恢复了祖先白菜型油菜（RBR）。然后通过将RBR与甘蓝型油菜供体进行杂交和回交，通过将其九条染色体中的每一条添加到提取的A亚基因组中，并建立整套单体异源附加系（MAALs），对C亚基因组进行原位剖析。来自春性甘蓝型油菜基因型“Oro”的RBR表现出一种类似于以前从未观察到的某种白菜型油菜的表型，但表现出冬性开花习性。与Oro相比，这种RBR的生长活力较弱，受到生物和非生物胁迫的影响更严重。这些MAALs特有的表型显示了相关基因在特定C亚基因组染色体上的位置。这些MAALs在同源配对和额外C亚基因组染色体的传递方面表现出明显不同的频率，这与它们的亲缘关系程度不同有关，甚至与甘蓝型油菜中减数分裂配对可能的遗传调控有关。最后，利用MAALs将甘蓝型油菜序列组装中未确定的大支架锚定到特定的C亚基因组染色体上。
