用ITS序列确定小麦B基因组的可能供体间的关系

对小麦B基因组的可能供体山羊草属Aegilops sect．Sitopsis的5个种的核糖体DNA的内部转 录区(ITS)进行了PCR扩增和克隆，井测定ITSl和ITS2的序列，用ITSl+ITS2的序列重建了 Aegilops sect．Sitopsis中5个种的系统发育关系。结果表明，斯卑尔脱山羊草Ae．speltoides是sect． Sitopsis中特殊的一个种，它与该组其余4种间的平均遗传距离是后者彼此间平均遗传距离的3倍，Ae． speltoides与同组其余4个种的分离要比后者相互间的分离早得多；在拟斯卑尔脱组Sect．Sitopsis的5 个种中，长柱山羊草Ae．longissima与沙融山羊草Ae．sharonensis的关系最近。ITS序列可以进一步用来作为确定B基因组起源的分子标记。

The phylogenetic relationships among the possible donors of B genome of common wheat based on internal transcribed spacer(ITS) sequences

The ITS regions of 5 species in Aegilops sect. Sitopsis, the possible donors of B genome of common wheat, were amplified by PCR, cloned and sequenced. The phylogenetic relationships among 5 species in Aegilops sect. Sitopsis were constructed based on ITS1 ITS2 sequences. The results demonstrated that Ae. speltoides was a distinct species in Aegilops sect. Sitopsis. The average of the pairwise distances between Ae. speltoides and the other four species was three times as high as that among the latter four. Ae. speltoides was the earliest lineage of the section under question. Relationship between Ae. longissima and Ae. sharonensis was the closest in Aegilops sect. Sitopsis. Sequence of ITS region could be used as a molecular marker to identify origin of B genome in polyploid wheats.