Ma Xue-Feng, Fang Peng, Gustafson J Perry
Department of Agronomy, University of Missouri, Columbia, MO 65211, USA.
Genome. 2004 Oct;47(5):839-48. doi: 10.1139/g04-051.
Polyploidization-induced genome variation in triticale (x Triticosecale Wittmack) was investigated using both AFLP and RFLP analyses. The AFLP analyses were implemented with both EcoRI-MseI (E-M) and PstI-MseI (P-M) primer combinations, which, because of their relative differences in sensitivity to cytosine methylation, primarily amplify repetitive and low-copy sequences, respectively. The results showed that the genomic sequences in triticale involved a great degree of variation including both repetitive and low-copy sequences. The frequency of losing parental bands was much higher than the frequency of gaining novel bands, suggesting that sequence elimination might be a major force causing genome variation in triticale. In all cases, variation in E-M primer-amplified parental bands was more frequent in triticale than that using P-M primers, suggesting that repetitive sequences were more involved in variation than low-copy sequences. The data also showed that the wheat (Triticum spp.) genomes were relatively highly conserved in triticales, especially in octoploid triticales, whereas the rye (Secale cereale L.) genome consistently demonstrated a very high level of genomic sequence variation (68%-72%) regardless of the triticale ploidy levels or primers used. In addition, when a parental AFLP band was present in both wheat and rye, the tendency of the AFLP band to be present in triticale was much higher than when it was present in only one of the progenitors. Furthermore, the cDNA-probed RFLP analyses showed that over 97% of the wheat coding sequences were maintained in triticale, whereas only about 61.6% of the rye coding sequences were maintained, suggesting that the rye genome variation in triticale also involved a high degree of rye coding sequence changes. The data also suggested that concerted evolution might occur in the genomic sequences of triticale. In addition, the observed genome variation in wheat-rye addition lines was similar to that in triticale, suggesting that wheat-rye addition lines can be used to thoroughly study the genome evolution of polyploid triticale.
利用AFLP和RFLP分析方法，对小黑麦（x Triticosecale Wittmack）中多倍体化诱导的基因组变异进行了研究。AFLP分析采用EcoRI-MseI（E-M）和PstI-MseI（P-M）两种引物组合，由于它们对胞嘧啶甲基化的敏感性存在相对差异，分别主要扩增重复序列和低拷贝序列。结果表明，小黑麦的基因组序列存在很大程度的变异，包括重复序列和低拷贝序列。丢失亲本条带的频率远高于获得新条带的频率，这表明序列消除可能是导致小黑麦基因组变异的主要力量。在所有情况下，小黑麦中E-M引物扩增的亲本条带变异比使用P-M引物更为频繁，这表明重复序列比低拷贝序列更多地参与了变异。数据还表明，小麦（Triticum spp.）基因组在小黑麦中相对高度保守，尤其是在八倍体小黑麦中，而黑麦（Secale cereale L.）基因组无论小黑麦的倍性水平或使用的引物如何，始终表现出非常高的基因组序列变异水平（68%-72%）。此外，当一个亲本AFLP条带同时存在于小麦和黑麦中时，该AFLP条带出现在小黑麦中的趋势远高于仅存在于一个亲本中的情况。此外，cDNA探针RFLP分析表明，超过97%的小麦编码序列在小黑麦中得以保留，而只有约61.6%的黑麦编码序列得以保留，这表明小黑麦中黑麦基因组变异也涉及高度的黑麦编码序列变化。数据还表明，小黑麦的基因组序列可能发生协同进化。此外，在小麦-黑麦附加系中观察到的基因组变异与小黑麦中的相似，这表明小麦-黑麦附加系可用于深入研究多倍体小黑麦的基因组进化。
