Development and molecular-genetic characterization of a stable Brassica allohexaploid
Development and molecular-genetic characterization of a stable Brassica allohexaploid
复制标题
DOI：
10.1007/s00122-016-2759-2
复制
发表时间：
2016-11-01
影响因子：
5.4
通讯作者：
Banga, Surinder Singh
中科院分区：
文献类型：
--
作者：
Gupta, Mehak;Atri, Chhaya;Banga, Surinder Singh
我们报告了稳定的芸苔属异源六倍体的首次合成。它可能进化成一个新物种，并促进我们对复杂异源多倍体中配对调控和基因组进化的理解。芸苔属作物包括单基因组和双基因组物种。自然界中尚不存在三基因组芸苔属（AABBCC）。由于减数分裂异常和自交后代中非整倍体植物比例非常高，过去合成稳定异源六倍体的尝试并未成功。我们报告了稳定的异源六倍体芸苔属（2n = 54；AABBCC）的发育。基因组原位杂交证实了三个基因组的完整组装。仅涉及 B. rapa cv. 的异源六倍体。 R01 (2n = 20; AA) 作为授粉媒介与一组 B. carinata (2n = 34; BBCC) 是稳定的。这些在自交后代中表现出高比例（0.78-0.94）具有正常减数分裂的花粉母细胞和极好的六倍体比例（0.80-0.94）。在印度两个非常不同的地点，从 H-1 到 H-4 代，两种异源六倍体组合的稳定性得到了证明。异源六倍体的图形基因分型允许检测三个基因组之间的染色体片段交换。与不稳定的异源六倍体相比，减数分裂稳定的异源六倍体的这些要小得多。推定的六倍体在叶形态、花序结构和花形状上在形态上更接近雌性供体 B. carinata。新形成的异源六倍体还可能提供独特的机会来研究具有三个常驻基因组的芸苔属异源六倍体的直接遗传和基因组后果。
We report first-time synthesis of a stable Brassica allohexaploid. It may evolve into a new species and also advance our understanding of pairing regulation and genome evolution in complex allopolyploids.Crop Brassicas include both monogenomic and digenomic species. A trigenomic Brassica (AABBCC) is not known to exist in nature. Past attempts to synthesize a stable allohexaploid were not successful due to aberrant meiosis and very high proportion of aneuploid plants in the selfed progenies. We report the development of a stable allohexaploid Brassica (2n = 54; AABBCC). Genomic in situ hybridization confirmed the complete assemblage of three genomes. Only allohexaploids involving B. rapa cv. R01 (2n = 20; AA) as pollinator with a set of B. carinata (2n = 34; BBCC) were stable. These exhibited a high proportion (0.78-0.94) of pollen mother cells with normal meiosis and an excellent hexaploid ratio (0.80-0.94) in the selfed progenies. Stability of two allohexaploid combinations was demonstrated from H-1 to H-4 generations at two very diverse locations in India. Graphical genotyping of allohexaploids allowed detection of chromosome fragment exchanges among three genomes. These were much smaller for meiotically stable allohexaploids as compared to unstable ones. The putative hexaploids were morphologically closer to the female donor, B. carinata, for leaf morphology, inflorescence structure and flower shape. The newly formed allohexaploid may also provide unique opportunities to investigate the immediate genetic and genomic consequences of a Brassica allohexaploid with three resident genomes.