节节麦和黑麦杂种F1及双二倍体中基因组变异分析

人工合成的双二倍体在遗传和植物育种中有重要作用。为探讨远缘杂交后代双二倍体育性提高及其细胞学稳定的分子机制，利用ALFP、MASP技术对节节麦-黑麦杂种及其双二倍体S₁~S₄代的基因组变异进行了分析。该双二倍的S₁~S₄代体细胞染色体数2n = 28的植株的比例从57.1%提高到92.5%，2n = 28的植株的花粉母细胞减数分裂中期二价体平均数目从11.7提高到12.25，平均结实率从24.5%提高到51.3%。利用两套分别扩增重复序列和单拷贝序列的酶切引物组合EcoR I/Mse I (E-M)、Pst I/Mse I (P-M)对节节麦–黑麦杂种F₁和双二倍体S₁~S₄代扩增表明，基因组序列变异主要发生于F₁代，且以序列消除为主。E-M和P-M引物扩增带中, 节节麦基因组在F₁代的序列消除带数占各代总消失带数的70.00%和52.95%，而在黑麦基因组为96.88%和81.64%。MSAP分析表明节节麦和黑麦杂种和加倍能够导致节节麦和黑麦基因组序列甲基化状态改变，以甲基化为主，仅发生在F₁和S₁代。在S₂~S₄代中没有检测到甲基化变异。

Genomic Variation in F1 Hybrid and Amphidiploid between Aegilops tauschii and Secale cereale

Synthetic amphidiploids play an important role in genetic study and plant breeding.To understand the molecular mechanism of fertility improvement and cytological stability in amphidiploid,we analyzed the fertility,genomic variation,and cytology of the F1 hybrid and S1 to S4 amphidiploid progenies from the cross between Aegilops tauschii and Secale cereale by means of microscopic observation and molecular markers(ALFP and MASP).The percentage of plants with chromosome number of 2n = 28 increased from 57.1% to 92.5% in the amphidiploid progenies.The bivalent in pollen mother cells(PMCs) at meiosis I stage increased from 11.70 to 12.25 averagely,and the mean rate of seed setting was enhanced from 24.5% to 51.3% in the amphidiploid progenies(2n=28).Genomic variation in the F1 hybrid and the amphidiploids was detected using AFLP markers digested by EcoR I/Mse I(E-M) and Pst I/Mse I(P-M),which could primarily amplify repetitive and low-copy sequences,respectively.The results showed that the genomic variation occurred mainly in the F1 hybrid with dominant form of sequence elimination.The loss percentages in F1 plants were 70.00% at E-M locus and 52.95% at P-M locus for the Ae.tauschii banding pattern and 96.88% at E-M locus and 81.64% at P-M locus for the S.cereale banding pattern.The result of MSAP analysis showed that the cytosine methylation alterations,mainly methylated,only occurred in the F1 hybrids and the S1 amphidiploids.In S2 to S4 amphidiploids,no methylation was observed.