Nelson Matthew N, Mason Annaliese S, Castello Marie-Claire, Thomson Linda, Yan Guijun, Cowling Wallace A
Faculty of Natural and Agricultural Sciences, School of Plant Biology, The University of Western Australia, Crawley, WA 6009, Australia.
Theor Appl Genet. 2009 Aug;119(3):497-505. doi: 10.1007/s00122-009-1056-8. Epub 2009 May 13.
We analysed the products of male meiosis in microspore-derived progeny from a Brassica napus (AAC(n)C(n)) x Brassica carinata (BBC(c)C(c)) interspecific hybrid (ABC(n)C(c)). Genotyping at 102 microsatellite marker loci and nuclear DNA contents provided strong evidence that 26 of the 28 progeny (93%) were derived from unreduced (2n) gametes. The high level of C(n)C(c) marker heterozygosity, and parallel spindles at Anaphase II in the ABC(n)C(c) hybrid, indicated that unreduced gametes were formed by first division restitution. The frequency of dyads at the tetrad stage of pollen development (2.6%) suggested that unreduced gametes were preferentially selected in microspore culture. Segregation of marker alleles in the microspore-derived progeny was consistent with homologous recombination between C(n) and C(c) chromosomes and homoeologous recombination involving A-, B- and C-genome chromosomes during meiosis in the ABC(n)C(c) hybrid. We discuss the potential for using microspore culture of unreduced gametes in interspecific hybrids to map Brassica centromeres through half-tetrad analysis.
我们分析了甘蓝型油菜（AAC(n)C(n)）与埃塞俄比亚芥（BBC(c)C(c)）种间杂种（ABC(n)C(c)）小孢子衍生后代中的雄配子减数分裂产物。在102个微卫星标记位点进行基因分型以及测定核DNA含量，有力地证明了28个后代中有26个（93%）源自未减数（2n）配子。ABC(n)C(c)杂种中C(n)C(c)标记的高杂合度以及后期II的平行纺锤体，表明未减数配子是通过第一次分裂 restitution形成的。花粉发育四分体阶段二分体的频率（2.6%）表明，未减数配子在小孢子培养中被优先选择。小孢子衍生后代中标记等位基因的分离与ABC(n)C(c)杂种减数分裂期间C(n)和C(c)染色体之间的同源重组以及涉及A、B和C基因组染色体的部分同源重组一致。我们讨论了利用种间杂种中未减数配子的小孢子培养通过半四分体分析绘制甘蓝型油菜着丝粒图谱的潜力。
