小麦-黑麦杂种体细胞无性系高配对突变体的细胞学和AFLP分析

Cytological and AFLP Analysis of the Wheat-Rye Somaclonal Variation with Higher Chromosome Pairing Rate

以小麦-黑麦未经组织培养直接结实杂种及幼胚无性系变异再生杂种为材料,观察再生杂种的花粉母细胞减数分裂中期Ι染色体配对情况,发现杂种幼胚无性系变异再生杂种中存在一些配对频率大幅度提高的突变体,表现在有多个二价体及三价体、四价体.利用原位杂交技术对未经组织培养直接结实杂种及高配对无性系杂种染色体的组成和结构分析,结果显示经过无性系变异提高了W-R、R-R间的联会,表明组织培养对小麦和黑麦染色体配对造成了一定影响;进而利用基因组AFLP技术研究亲本和两种类型的杂种DNA序列上的差异,结果表明各种类型的杂种F1代均发生了广泛的基因组改变,主要表现为小麦、黑麦两亲本片段的缺失,且高配对无性系杂种基因组的变异大于未经组织培养直接结实杂种.本研究为进一步探究高配对变异的分子机理并利用该变异进行染色体重组奠定了基础.

Previous cytological analysis of the wheat×rye hybrids revealed a high frequency of bivalents at metaphase I in some somaclonal variation in the embryogenic cell culture. In order to determine the molecular nature of the change, the hybrids non-regenerated from tissue culture and the somaclonal variation with higher number of chromosome pairing were examined by genomic in situ hybridization （GISH） and the amplified fragment length polymorphism （AFLP） technique. It is indicated that somaclonal variation gave rise to pairing configuration of W-R and R-R. Furthermore, the source and type of genomic changes were investigated that extensive genomic changes were observed as early as F1 in all hybrids, and that the major variation was the parents＇ sequence elimination. Moreover, the change of somaclonal variation with higher number of chromosome pairing was much larger than that of the hybrids non-regenerated from tissue culture. The result suggested that the somaclonal variation could increase the genomic changes. It is the first time to report the cytology and the molecular biology foundation of high frequent pairing variation.