人工合成芸薹属异源六倍体的细胞遗传学研究

发布时间：2018-03-26 16:15

本文选题：合成芸薹属种　切入点：远缘杂交　出处：《华中农业大学》2016年博士论文

【摘要】：芸薹属三个栽培二倍体种(白菜型油菜、甘蓝、黑芥)间的成对杂交形成了三个栽培异源四倍体种(甘蓝型油菜、芥菜型油菜、埃塞俄比亚芥),但自然界没有发现倍性更高的芸薹属种存在。本研究通过芸薹属六个栽培种间的三种杂交途径合成芸薹属三基因组异源六倍体(2n=54,AABBCC),并进行连续世代的形态、育性及分子细胞学分析,获得如下主要结果:1.通过三个二倍体间的顺序杂交及染色体加倍([B.rapa×B.oleracea var.alboglabra]×B.nigra,[B.oleracea var.alboglabra×B.rapa]×B.nigra)产生两个异源六倍体(ArAr.CoCo.BiBi/CoCo.ArAr.BiBi,染色体组的上标符号显示其来源的亲本种,如来自B.rapa的染色体组为ArAr),分别具有白菜型油菜(B.rapa,2n=20,AA)及芥蓝(B.oleracea var.alboglabra,2n=18,CC)的细胞质。以芥菜型油菜(B.juncea,2n=36,AABB)为母本与芥蓝杂交及杂种染色体加倍产生异源六倍体(AjAjBjBj.CoCo),并自交三代。以前通过埃塞俄比亚芥(B.carinata,2n=34,BBCC)和小白菜(B.rapa ssp.chinensis,2n=20,AA)杂交合成的异源六倍体(BcBcCcCc.ArAr)的自交后代(S5-S7)。2.这四个芸薹属三基因组异源六倍体连续自交多代后,我们调查了表型、花粉育性、角果结实率及用双色原位杂交分析了染色体组成和基因组的稳定性。C基因组和B基因组染色体特性的探针做原位杂交,可以很好的区分三个基因组。从而我们可以在六倍体后代中鉴定不同的染色体数量及核型,和减数分裂中不同基因组的染色体行为,如基因组内的同源配对和基因组间的非同源配对。在后代中整倍体和非整倍体都鉴定到了。在绝大多数的非整倍体中都保持了完整的B基因组染色体和大部分的A基因组染色体及由不同数量的C基因组染色体,这表明了基因组染色体的稳定性梯度为BAC。在极端的单株中,丢失了所以的C基因组的染色体,导致形成了芥菜型油菜核型的后代。有些非整倍体后代有和整倍体六倍体的染色体数(2n=54)一样的染色体数,但是丢失或获得了一些A/C基因组染色体。在所有六倍体连续的后代的整倍体中,减数分裂中的二倍体化和非二倍体化的减数分裂行为都共同存在。不正常的染色体配对和分离主要在A和C基因组染色体中,这导致了在自交后代的非整倍体的出现。3.不同杂交途径来源的新形成的芸薹属异源六倍体中,连续的自交中都显示了基因组的稳定性差异。在绝大多数后代中B基因组的染色体都完整的保留下来,而C基因组染色体最容易丢失,A基因组染色体的改变程度小于C基因组。染色体数目的变化只存在于不同的单株间,而没有在同一单株内,这说明在有丝分裂过程中没有染色体消除。总体说,这些六倍体表现了正常的染色体配对和分离贡献了代际间整倍体六倍体遗传稳定。而不正常的A/C基因组间染色体的配对和分离导致了代际间的A/C基因组的连续丢失。特别的是,在六倍体AjAjBjBj.CoCoS3后代中,所有C基因组染色体消除后导致了恢复到母本的芥菜型油菜类型。相似的在BcBcCcCc.ArAr S7中也有单株回复到芥菜型油菜(ArArBcBc)的状态,这新型芥菜油菜保持了来自天然白菜的A基因组和天然埃塞俄比亚芥的B基因组。因此这些六倍体的后代的染色体数变异范围是从整倍六倍体到芥菜型油菜B.juncea(2n=36,AABB)。二体遗传和非二体遗传减数分裂染色体行为导致了这些连续的代际间的整倍体和非整倍体遗传。在这些人工合成的芸薹属异源六倍体中,染色体变异的范围大大于人工合成的异源四倍体甘蓝型油菜和人工合成的异源六倍体小麦。这表明在这些新合成的异源多倍体中组成的基因组来说,不同的基因组和倍性水平有不同的稳定性。在人工合成的芸薹属异源六倍体中的减数分裂驱动的不同基因组的稳定性差异,可能和芸薹属B/A/C三个基因组内在固有的基因组性质及相互关系有关。本研究的结果提供了在异源多倍体化的早期阶段,不同基因组细胞遗传学形为差异的新的理解。
[Abstract]:Three cultivated Brassica diploid species (Brassica napus, Brassica nigra, hybridization between pairs) formed three cultivated tetraploid species (Brassica napus, Brassica juncea, Ethiopia mustard), but found no more times the nature of Brassica species. This study by Brassica six three a hybrid approach between the cultivars of brassica genome synthesis three Yiyuan six ploidy (2n=54, AABBCC), and successive generations of morphology, fertility and molecular cytological analysis, the main results are as follows: 1. through three diploid sequence of hybridization and chromosome doubling ([B.rapa * B.oleracea var.alboglabra] * B.nigra, [B.oleracea * var.alboglabra B.rapa] * B.nigra) produced two Yiyuan six ploidy (ArAr.CoCo.BiBi/CoCo.ArAr.BiBi, genome superscript symbol display the source of the parental species, such as B.rapa ArAr, genome) respectively. With Brassica napus (B.rapa, 2n=20, AA) and Gai Lan (B.oleracea var.alboglabra, 2n=18, CC) in the cytoplasm. In Brassica juncea (B.juncea, 2n=36, AABB) as the female parent and Gai Lan produce heterologous hybridization and hybrid chromosome doubling six times (AjAjBjBj.CoCo), and three self generation. Previously by Ethiopia mustard (B.carinata, 2n=34, BBCC) and Chinese Cabbage (B.rapa ssp.chinensis, 2n=20, AA) synthesis of heterologous hybridization (BcBcCcCc.ArAr) was six times as much as the progeny of.2. (S5-S7) of the four brassica genome three heterologous six times continuous after many generations, we investigated the phenotype, pollen fertility, seed setting rate and the probe chromosomes and genomic stability of.C genome and B genome chromosome analysis of the characteristics of double color in situ hybridization in situ hybridization, it can distinguish the three genome. Thus we can in six different ploidy offspring in identification of dye Body color number and karyotype, chromosome behavior in meiosis and different genomes, such as genome homologous pairing and non homologous pairing between genomes. In the progeny of euploid and aneuploid were identified. Aneuploidy remained intact chromosome B gene group and most of the A the genome of chromosome and C genome chromosomes from different numbers in most, which indicated that the stability of chromosome is BAC. gradient in extreme plants, so lost C genome chromosomes, leading to the formation of the Brassica juncea karyotype after generation. Some aneuploid offspring and aneuploidy six times the number of chromosomes (2n=54) chromosome number of the same, but lost or gained some A/C genome chromosomes in the offspring. All six times consecutive euploid, meiosis of diploid and non diploid of reduction The number of split behavior are common. Chromosome pairing and separation is not normal in the A and C genome chromosome aneuploidy, which resulted in the progeny of the.3. hybrid sources of newly formed Brassica Yiyuan six ploidy, continuous selfing showed differences of genome stability in the vast majority of offspring. Keep the chromosomes of the B genome are completely down, and C genome chromosomes are the most easily lost, the change degree of A genome chromosome genome is less than C. The change of the chromosome number only exists in different plants, but not in the same plant, indicating that eliminated during mitosis without chromosome. Overall, these six ploidy showed normal chromosome pairing and separation between generations with aneuploidy was six times as much as the genetic stability. Instead of the normal A/C genome chromosome pairing and Separation leads to continuous loss of intergenerational A/C genome. In particular, at six times the AjAjBjBj.CoCoS3 offspring, eliminate all C genome chromosomes resulted in a return to the female parent of Brassica juncea type. Similar in BcBcCcCc.ArAr S7 has returned to plant Brassica juncea (ArArBcBc) state, this type of mustard keep the cabbage rape from natural and natural Ethiopia mustard A genome B genome. So the range of chromosome ploidy of these six offspring from six times to the whole body of Brassica juncea B.juncea (2n=36, AABB). Two genetic and non genetic two meiotic chromosome behavior led to the continuous intergenerational euploid and aneuploid genetic. In these synthetic Brassica Yiyuan six times in the range of chromosomal variation over synthetic allotetraploid Brassica napus And heterologous six synthetic hexaploid wheat. This shows that in these newly synthesized allopolyploids in the genome, the genome and different ploidy levels have different stability. The stability of different genomes in meiosis of synthetic Brassica Yiyuan six ploidy division in the genome driven, nature and mutual may and three B/A/C of brassica genome inherent. The results of this study provide in the early stage of polyploidization of different genomic cytogenetic shape is new understanding of the differences.

【学位授予单位】：华中农业大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：S184

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