野黄瓜与栽培黄瓜正反交异源四倍体序列消除的初步研究

Preliminary studies on sequence elimination of reciprocal allotetraploids from Cucumis hystrix and C. sativus

不同分类群的异源多倍体在二倍化过程中,正反交序列消除往往表现出不同特征,暗示了在不同物种中,核质互作在多倍体进化过程的作用不同。利用13对EcoRI-NN/MseI-NNN选择性引物,对野黄瓜Cucumishystrix(2n=24)与栽培黄瓜C.sativus(2n=14)的正反交F1、异源四倍体及二倍体亲本DNA进行AFLP分析。结果表明:杂交后代基因组的杂合性诱发了F1与异源四倍体广泛的序列消除;细胞质可能会影响部分亲本序列消除的频率,但是正反交在序列消除频率上差异不显著,并且在序列消除时间(均始于F1代)及消除类型上也表现出一致性,表明核质互作并不是影响序列消除的主要因素;实验还发现,正反交不能影响序列的倾向性丢失,染色体数少的黄瓜条带易发生丢失。

During diploidization, sequence elimination in reciprocal allopolyploids often appears variable in different species, suggesting that the nuclear-cytoplasmic interactions play different roles in different polyploid plants. In this study, an amplified fragment length polymorphism （AFLP） analysis was carried out by using thirteen pairs of EcoRI-NN/MseI-NNN selective primers in amplification of the DNAs from reciprocal F1 hybrids of Cucumis hystrix and C. sativus, the synthetic allotetraploids and the diploid parents. The results indicated that extensive DNA sequence elimination was induced by the genomic merge in the allopolyploids. The frequency of elimination of some parental sequences was affected by cytoplasmic factors, the differences from reciprocal crosses were not statistically significant, and the time of elimination （both started in the F1） and the type of elimination were also the same, suggesting that the nuclear-cytoplasmic interactions might not be the main factor causing sequence elimination. In addition, the direction of sequence elimination was not affected by the reciprocal crosses, and the elimination was more common from the C. sativus which has fewer chromosomes.