Han Yuepeng, Bendik Elise, Sun Feng-Jie, Gasic Ksenija, Korban Schuyler S
Department of Natural Resources and Environmental Sciences, University of Illinois, Urbana, IL 61801, USA.
Planta. 2007 Oct;226(5):1265-76. doi: 10.1007/s00425-007-0555-6. Epub 2007 Jun 13.
Two genes encoding starch branching enzyme II (SBEII) have been identified in apple. These genes share 94 and 92% identity in coding DNA sequences and amino acid sequences, respectively; moreover, they have similar expression patterns. Both genes are expressed in vegetative and reproductive tissues, including leaves, buds, flowers, and fruits. Based on genomic Southern blots, there are two copies of SbeII genes in the apple genome. Comparisons of genomic sequences between monocots and eudicots have revealed that the genomic structure of SbeII genes is conserved. However, the 5'-terminal region of coding DNA sequences of SbeII genes shows greater divergence than the 3'-terminal region between monocots and eudicots. Phylogenetic analysis of DNA sequences has demonstrated that the duplication patterns of SbeII genes are different between monocots and eudicots. In monocots, the duplication of SbeII genes must have occurred prior to the radiation of grasses (Poaceae); while, in eudicots, the expansion of SbeII genes must have followed the process of speciation.
在苹果中已鉴定出两个编码淀粉分支酶II（SBEII）的基因。这些基因在编码DNA序列和氨基酸序列中的同一性分别为94%和92%；此外，它们具有相似的表达模式。这两个基因在营养组织和生殖组织中均有表达，包括叶片、芽、花和果实。基于基因组Southern杂交分析，苹果基因组中有两个SbeII基因拷贝。单子叶植物和双子叶植物基因组序列的比较表明，SbeII基因的基因组结构是保守的。然而，单子叶植物和双子叶植物之间，SbeII基因编码DNA序列的5'末端区域比3'末端区域表现出更大的差异。DNA序列的系统发育分析表明，单子叶植物和双子叶植物中SbeII基因的复制模式不同。在单子叶植物中，SbeII基因的复制肯定发生在禾本科植物分化之前；而在双子叶植物中，SbeII基因的扩增肯定是在物种形成过程之后发生的。
