Schelfhout C J, Snowdon R, Cowling W A, Wroth J M
School of Plant Biology, Faculty of Natural and Agricultural Sciences, The University of Western Australia, 35 Stirling Hwy, Crawley, WA 6009, Australia.
Genome. 2006 Nov;49(11):1490-7. doi: 10.1139/g06-103.
We used polymerase chain reaction (PCR) and fluorescence in situ hybridization (FISH) techniques to demonstrate the presence of Brassica B-genome chromosomes and putative B-genome introgressions in B. napus x B. juncea interspecific progeny. The B-genome--specific repeat sequence pBNBH35 was used to generate PCR products and FISH probes. The highest frequencies of viable progeny were obtained when B. napus was the maternal parent of the interspecific hybrid and the first backcross. B-genome--positive PCR assays were found in 34/51 fertile F2 progeny (67%), which was more than double the proportion found in fertile BC(1) progeny. Four B-genome--positive F(2)-derived families and 1 BC(1)-derived family were fixed or segregating for B. juncea morphology in the F(4) and BC(1)S(2), respectively, but in only 2 of these families did B. juncea-type plants exhibit B. juncea chromosome count (2n = 36) and typical B-genome FISH signals on 16 chromosomes. The remaining B. juncea-type plants had B. napus chromosome count (2n = 38) and no B-genome FISH signals, except for 1 exceptional F(4)-derived line that exhibited isolated and weak B-genome FISH signals on 11 chromosomes and typical A-genome FISH signals. B. juncea morphology was associated with B-genome--positive PCR signals but not necessarily with 16 intact B-genome chromosomes as detected by FISH. B-genome chromosomes tend to be eliminated during selfing or backcrossing after crossing B. juncea with B. napus, and selection of lines containing B-genome chromatin during early generations would be promoted by use of this B-genome repetitive marker.
我们使用聚合酶链反应（PCR）和荧光原位杂交（FISH）技术，来证明甘蓝型油菜（B. napus）与芥菜型油菜（B. juncea）种间后代中芸苔属B基因组染色体的存在以及假定的B基因组渐渗。利用B基因组特异的重复序列pBNBH35来生成PCR产物和FISH探针。当甘蓝型油菜作为种间杂种及其第一次回交的母本时，获得了最高频率的可存活后代。在51株可育的F2后代中，有34株（67%）的B基因组PCR检测呈阳性，这一比例是可育BC(1)后代中该比例的两倍多。分别在F(4)和BC(1)S(2)中，有四个源自F(2)的B基因组阳性家系和一个源自BC(1)的家系在芥菜型油菜形态上固定或分离，但在这些家系中，只有2个家系的芥菜型油菜植株显示出芥菜型油菜的染色体数（2n = 36）以及16条染色体上典型的B基因组FISH信号。其余的芥菜型油菜植株具有甘蓝型油菜的染色体数（2n = 38），并且没有B基因组FISH信号，除了一个例外的源自F(4)的株系，该株系在11条染色体上显示出孤立且微弱的B基因组FISH信号以及典型的A基因组FISH信号。芥菜型油菜形态与B基因组阳性PCR信号相关，但不一定与FISH检测到的16条完整的B基因组染色体相关。在用芥菜型油菜与甘蓝型油菜杂交后的自交或回交过程中，B基因组染色体往往会被消除，使用这种B基因组重复标记将有助于在早期世代中选择含有B基因组染色质的株系。
