Functional Specialization of Duplicated AGAMOUS Homologs in Regulating Floral Organ Development of Medicago truncatula.
Functional Specialization of Duplicated AGAMOUS Homologs in Regulating Floral Organ Development of Medicago truncatula.
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重复的 AGAMOUS 同源物在调节蒺藜苜蓿花器官发育中的功能特化
DOI：
10.3389/fpls.2018.00854
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发表时间：
2018
影响因子：
5.6
通讯作者：
Lin H
中科院分区：
文献类型：
--
作者：
Zhu B;Li H;Wen J;Mysore KS;Wang X;Pei Y;Niu L;Lin H
C功能基因AGAMOUS(AG)编码被子植物花器官识别和花分生组织(FM)决定所需的MADS盒转录因子。与拟南芥不同，大多数豆科植物都有两个AG同源物，这两个同源物是由古老的基因组复制事件引起的。最近，在模式豆科牧草紫花苜蓿中发现了两个具有C功能活性的辅酶基因MtAgA和MtAGb。在这里，我们报告了通过筛选Medicago Tnt1插入突变体集合来分离和鉴定一个新的maga等位基因。我们发现，MtAGA不仅是控制雄蕊和心皮特性所必需的，而且还影响角果和种子的发育。遗传分析表明，MtAGA和MtAGb冗余地控制着紫花苜蓿的花器官特性，但对雄蕊和心皮发育的调节作用不明显，呈剂量依赖关系。有趣的是，在与拟南芥不同的双突变体mtag中，雄蕊和心皮大多转化为大量的维管束状花瓣。进一步对不同mtag突变体的qRT-PCR分析表明，MtAGa和MtAGb能够抑制可能的A、B功能基因和MtWUS的表达，但促进可能的D功能基因的表达。此外，我们还发现在mtag-mtag b双突变体中观察到的异常的背瓣表型与类Cycloidae(CyC)类TCP基因的上调有关。综上所述，我们的数据表明，MtAGa和MtAGb的冗余基因在决定花器官特性和FM决定性方面采用了与拟南芥相似的保守作用机制，但可能通过与特定的花背腹特性因子协调而在调节花对称性方面进化了不同的功能。
The C function gene AGAMOUS (AG) encodes for a MADS-box transcription factor required for floral organ identity and floral meristem (FM) determinacy in angiosperms. Unlike Arabidopsis, most legume plants possess two AG homologs arose by an ancient genome duplication event. Recently, two euAGAMOUS genes, MtAGa and MtAGb, were characterized and shown to fulfill the C function activity in the model legume Medicago truncatula. Here, we reported the isolation and characterization of a new mtaga allele by screening the Medicago Tnt1 insertion mutant collection. We found that MtAGa was not only required for controlling the stamen and carpel identity but also affected pod and seed development. Genetic analysis indicated that MtAGa and MtAGb redundantly control Medicago floral organ identity, but have minimal distinct functions in regulating stamen and carpel development in a dose-dependent manner. Interestingly, the stamens and carpels are mostly converted to numerous vexillum-like petals in the double mutant of mtaga mtagb, which is distinguished from Arabidopsis ag. Further qRT-PCR analysis in different mtag mutants revealed that MtAGa and MtAGb can repress the expression of putative A and B function genes as well as MtWUS, but promote putative D function genes expression in M. truncatula. In addition, we found that the abnormal dorsal petal phenotype observed in the mtaga mtagb double mutant is associated with the upregulation of CYCLOIDEA (CYC)-like TCP genes. Taken together, our data suggest that the redundant MtAGa and MtAGb genes of M. truncatula employ a conserved mechanism of action similar to Arabidopsis in determining floral organ identity and FM determinacy but may have evolved distinct function in regulating floral symmetry by coordinating with specific floral dorsoventral identity factors.
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影响因子：
64.8
作者：
Luo, D;Carpenter, R;Coen, E
通讯作者：
Coen, E
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