摘要
对普通小麦（ＴｒｉｔｉｃｕｍａｅｓｔｉｖｕｍＬ．）基因组（ＡＡＢＢＤＤ）最可能的供体———Ｔ．ｕｒａｒｔｕＴｈｕｍ．（ＡＡ）、Ｔ．ｍｏｎｏｃｏｃｕｍｖａｒ．ｂｏｅｏｔｉｃｕｍ（Ｂｏｉｓ．）ＭＫ（ＡＡ）、ＡｅｇｉｌｏｐｓｓｐｅｌｔｏｉｄｅｓＴａｕｓｃｈ．和Ａｅ．ｔａｕｓｃｈｉＣｏｓ．（ＤＤ）的核糖体ＲＮＡ基因ＩＴＳ区进行了ＰＣＲ扩增和克隆，并测定了ＩＴＳ１和ＩＴＳ２的ＤＮＡ序列，讨论和纠正了前人的结论。四个种中，ＩＴＳ１长２２１～２２３ｂｐ，ＩＴＳ２长２１６～２１７ｂｐ。ＩＴＳ１序列的种间分化距离范围为０．０２９０～０．０６４０，ＩＴＳ２的为０．００９３～０．０５８０。根据ＩＴＳ１、ＩＴＳ２以及ＩＴＳ１＋ＩＴＳ２序列都得出相同的一个最大简约树，所揭示的亲缘关系与这些种的形态学和细胞学特征相一致。在每一个分支树中，Ｔ．ｕｒａｒｔｕ和Ｔ．ｍｏｎｏｃｏｃｕｍｖａｒ．ｂｏｅｏｔｉｃｕｍ构成一个单系类群，Ａｅ．ｓｐｅｌｔｏｉｄｅｓ和Ａｅ．ｔａｕｓｃｈｉ构成另一个单系类群，前一分支的ｂｏｏｔｓｔｒａｐ值高于后一分支。
The ITS1 and ITS2 of rDNA of four diploid species, newly Triticum urartu Thum. (AA), T.monococcum var. boeoticum (Boiss.) MK (AA),Aegilops speltoides Tausch. (BB) and Ae. tauschii Coss. (DD), the most possible donors of A,B and D genomes to bread wheat (T. aestivum), were amplified by PCR, cloned and sequenced. Some published sequences were discussed and rectified. The length of ITS1 sequences in four species was 221 to 223 bp, and that of ITS2 was 216 to 217 bp. In pairwise sequence comparisons among four species, divergence ranged from 0.0290 to 0.0640 in ITS1, and from 0.0093 to 0.0580 in ITS2. Based on ITS1,ITS2 and ITS1+ITS2 data respectively, the same most parsimony tree that is congruent with the phylogenetic relationships was generated which was concordant with their morphological and cytological characteristics. In the trees, T.urartu and T.monococcum var. boeoticum constituted one monophyly, whereas two species of the genus Aegilops, Ae.speltoides and Ae. tauschii, formed another monophyly but with lower bootstrap value than the first clade. This study suggests that ITS region is a useful molecular marker in the studies on the origin and evolution of Triticum.
基金
北京大学蛋白质工程及植物基因工程国家重点实验室资助
