The classification of tetraploid wheat by phylogenetic and cytogenetic analyses
The classification of tetraploid wheat by phylogenetic and cytogenetic analyses
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通过系统发育和细胞遗传学分析对四倍体小麦进行分类
DOI：
10.32615/bp.2020.013
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发表时间：
2020-01-01
影响因子：
1.5
通讯作者：
Kang, H. -Y.
中科院分区：
文献类型：
--
作者：
Li, S. -Y.;Xi, L.;Kang, H. -Y.
四倍体小麦（Triticum turgidum L.）是小麦属的一个重要品种，具有许多优良的农艺性状。四倍体小麦的分类、起源和演化一直存在着混乱和争议，导致种质资源的浪费。四倍体小麦广泛采用两种分类体系：1)四倍体小麦分为两种；2)将所有四倍体小麦归为一种。本研究旨在利用核rDNA内转录间隔区（ITS）序列数据的系统发育分析、荧光原位杂交（FISH）核型分析和观察F1杂种的减数分裂配对行为，对小麦的四倍体分类进行重新评价。ITS序列的网络分析表明，四倍体小麦与其他小麦科植物（除Aegilops speltoides和Ae.）的亲缘关系并不密切。sharonensis。ITS序列和FISH的系统发育分析表明，膨松小麦和timopheevi聚在不同的分支上，这两种杂种F1的减数分裂配对表现出较高的单价配对频率。在F1杂交体的减数分裂行为中，除了T. turgidum ssp外，其他不同形式的T. turgidum的单价数很少（平均值< 2）。dicoccoides。在FISH杂交模式中，在1A、2A、5A、1B、2B、3B和6B染色体上观察到显著差异。双头绦虫和其他肿头绦虫。此外，ITS系统发育分析的结果与减数分裂行为和FISH核型的观察结果密切相关。本研究结果表明，turgidum和timopheevi是两个不同起源的远亲种。膨松小麦。双头绦虫应保持为肿头绦虫的亚种，而其他肿头绦虫应重新归类为变种。
Tetraploid wheat (Triticum turgidum L.) is an important species within the genus Triticum and harbors many desirable agronomic traits. The classification, origin, and evolution of tetraploid wheat remain confused and controversial, resulting in useless germplasm resources. Two classification systems for tetraploid wheat are widely used: 1) tetraploid wheat comprises two species; 2) all forms of tetraploid wheat are classified as one species. The present study aimed to reassess the classification of tetraploid wheat using phylogenetic analysis of nuclear rDNA internal transcribed spacer region (ITS) sequence data, fluorescence in situ hybridization (FISH) karyotyping, and observation of meiotic pairing behavior in F1 hybrids. Network analysis of ITS sequences indicates that tetraploid wheat was not closely related to other Triticeae species with the exception of Aegilops speltoides and Ae. sharonensis. Phylogenetic analysis of ITS sequences and FISH show that Triticum turgidum and T. timopheevii clustered on distinct branches, and meiotic pairing in F1 hybrids of these species showed a high frequency of univalents. Meiotic behavior of F1 hybrids among forms of T. turgidum revealed a low number of univalents (means < 2) except for T. turgidum ssp. dicoccoides. The significant variation on chromosomes 1A, 2A, 5A, 1B, 2B, 3B, and 6B in the FISH hybridization patterns were observed between T. turgidum ssp. dicoccoides and other T. turgidum accessions. Furthermore, the results of ITS phylogenetic analyses correspond closely with observations of meiotic behavior and FISH karyotyping. The present results indicate that T. turgidum and T. timopheevii are two distantly related species of different origins. Triticum turgidum ssp. dicoccoides should be maintained as a subspecies of T. turgidum whereas other forms of T. turgidum should be reclassified as varieties.