Introduction

Until now, the most likely direct maternal progenitor (AABB) for common wheat (AABBDD) has yet to be identified. Here, we try to solve this particular problem with the specificity of a novel gene family in wheat and by using large population of rare germplasm resources.

Objectives

Dissect the novelty of TaCAF1Ia subfamily in wheat. Exploit the conservative and specific characteristics of TaCAF1Ia1 to reveal the origin of the maternal progenitor for common wheat.

Methods

Phylogenetic and collinear analysis of TaCAF1 genes were performed to identify the evolutionary specificity of TaCAF1Ia subfamily. The large-scale expression patterns and interaction patterns analysis of CCR4-NOT complex were used to clarify the expressed and structural specificity of TaCAF1Ia subfamily in wheat. The population resequencing and phylogeny analysis of the TaCAF1Ia1 were utilized for the traceability analysis to understand gene-pool exchanges during the transferring and subsequent development from tetraploid to hexaploidy wheat.

Results

TaCAF1Ia is a novel non-typical CAF1 subfamily without DEDD (Asp-Glu-Asp-Asp) domain, whose members were extensively duplicated in wheat genome. The replication events had started and constantly evolved from ancestor species. Specifically, it was found that a key member CAF1Ia1 was highly specialized and only existed in the subB genome and S genome. Unlike CAF1s reported in other plants, TaCAF1Ia genes may be new factors for anther development. These atypical TaCAF1s could also form CCR4-NOT complex in wheat but with new interaction sites. Utilizing the particular but conserved characteristics of the TaCAF1Ia1 gene, the comparative analysis of haplotypes composition for TaCAF1Ia1 were identified among wheat populations with different ploidy levels. Based on this, the dual-lineages origin model of maternal progenitor for common wheat and potential three-lineages domestication model for cultivated tetraploid wheat were proposed.

Conclusion

This study brings fresh insights for revealing the origin of wheat and the function of CAF1 in plants.

中文翻译：

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对 CAF1 家族进化的新见解和利用 TaCAF1Ia1 特异性揭示普通小麦母系祖细胞的起源

介绍

到目前为止，尚未确定普通小麦 (AABBDD) 最可能的直接母系祖细胞 (AABB)。在这里，我们试图利用小麦中一个新基因家族的特异性和大量稀有种质资源来解决这一特殊问题。

目标

剖析小麦中 TaCAF1Ia 亚科的新颖性。利用TaCAF1Ia1的保守和特异性特征来揭示普通小麦母系祖细胞的起源。

方法

对TaCAF1基因进行系统发育和共线分析，以确定 TaCAF1Ia 亚家族的进化特异性。CCR4-NOT 复合物的大规模表达模式和相互作用模式分析用于阐明 TaCAF1Ia 亚家族在小麦中的表达和结构特异性。TaCAF1Ia1的种群重测序和系统发育分析用于溯源性分析，以了解从四倍体小麦到六倍体小麦的转移和后续发育过程中的基因库交换。

结果

TaCAF1Ia 是一个新的非典型 CAF1 亚家族，没有 DEDD (Asp-Glu-Asp-Asp) 结构域，其成员在小麦基因组中被广泛复制。复制事件已经开始，并不断从祖先物种进化而来。具体来说，发现一个关键成员CAF1Ia1高度特化，只存在于subB基因组和S基因组中。与其他植物中报道的CAF1不同， TaCAF1Ia基因可能是花药发育的新因素。这些非典型 TaCAF1 也可以在小麦中形成 CCR4-NOT 复合物，但具有新的相互作用位点。利用TaCAF1Ia1基因特殊但保守的特性，比较分析TaCAF1Ia1的单倍型组成在具有不同倍性水平的小麦种群中被鉴定出来。在此基础上，提出了普通小麦母本双系起源模型和栽培四倍体小麦潜在三系驯化模型。

结论

这项研究为揭示小麦的起源和CAF1在植物中的功能带来了新的见解。