Genome change in wheat observed through the structure and expression of α/β-gliadin genes
Genome change in wheat observed through the structure and expression of α/β-gliadin genes
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DOI：
10.1007/s10142-012-0269-0
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发表时间：
2012-06-01
影响因子：
2.9
通讯作者：
Ogihara, Y.
中科院分区：
文献类型：
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作者：
Kawaura, K.;Wu, J.;Ogihara, Y.
为了更好地了解六倍体小麦的基因组结构和α / β -麦胶蛋白多基因的表达，筛选了含有Gli-A2、Gli-B2和Gli-D2三个基因座α / β -麦胶蛋白基因的细菌人工染色体（BAC）克隆。根据它们的限制性片段模式，我们选择了5个BAC克隆，即2个Gli-A2克隆、2个Gli-B2克隆和1个Gli-D2克隆进行全测序。每个基因座测序约200kb。在每个BAC克隆中共发现12个α / β -麦胶蛋白完整基因和4个假基因，并存在反转录转座子或其他转座子。点图分析揭示了各BAC内基因组片段重复的模式。我们计算了每组α / β麦胶蛋白基因复制和反转录转座子插入的时间。同一BAC无性系内所有邻近基因的重复发生在异源四倍体分化之前或之后，但某些基因的重复发生在小麦品种二倍体分化之前。逆转录转座子也在片段复制事件前后插入。此外，α / β -麦胶蛋白基因从1到6号染色体的易位显然发生在各种小麦基因组多样化之前。含有α / β -麦胶蛋白基因和反转录转座子的基因组片段的重复是通过不平等交叉或跳跃复制引起的，α / β -麦胶蛋白基因本身的复制没有任何重组事件。在从序列中检测到的12个完整的α / β麦胶蛋白基因中，有9个基因得到了表达，尽管它们的表达模式不同。由于它们具有相似的顺式元件和启动子结构，本文讨论了它们不同基因表达的机制和可能的应用。
To better understand genome structure and the expression of alpha/beta-gliadin multigenes in hexaploid wheat, bacterial artificial chromosome (BAC) clones containing alpha/beta-gliadin genes from the three loci, Gli-A2, Gli-B2, and Gli-D2, were screened. Based on their restriction fragment patterns, we selected five BAC clones, namely, two clones for Gli-A2, two clones for Gli-B2, and one clone for Gli-D2, to fully sequence. Approximately 200 kb was sequenced for each locus. In total, twelve alpha/beta-gliadin intact genes and four pseudogenes were found, and retrotransposons or other transposons existed in each BAC clone. Dot-plot analysis revealed the pattern of genome segmental duplication within each BAC. We calculated time since duplication of each set of alpha/beta-gliadin genes and insertion of retrotransposons. Duplication of all adjacent genes within the same BAC clone took place before or after allotetrapolyploidization, but duplication of certain genes occurred before diploid differentiation of wheat species. Retrotransposons were also inserted before and after the segmental duplication events. Furthermore, translocation of alpha/beta-gliadin genes from chromosomes 1 to 6 apparently occurred before the diversification of various wheat genomes. Duplication of genome segments containing alpha/beta-gliadin genes and retrotransposons were brought about through unequal crossing-over or saltatory replication and alpha/beta-gliadin genes per se were duplicated without any recombination events. Out of twelve intact alpha/beta-gliadin genes detected from their sequences, nine were expressed, although their patterns of expression were distinct. Since they have similar cis-elements and promoter structures, the mechanisms underlying their distinct gene expression and possible applications are discussed.