Isolation and Characterization of the C-class MADS-box Gene from the Distylous Pseudo-cereal Fagopyrum esculentum
Isolation and Characterization of the C-class MADS-box Gene from the Distylous Pseudo-cereal Fagopyrum esculentum
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从二柱状假谷物 Fagopyrum esculentum 中分离和表征 C 类 MADS-box 基因
DOI：
10.1007/s12374-016-0488-3
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发表时间：
2017-04-01
影响因子：
2.9
通讯作者：
Liu, Zhi-Xiong
中科院分区：
文献类型：
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作者：
Li, Lai-Yun;Fang, Zheng-Wu;Liu, Zhi-Xiong
在模式植物拟南芥中，花同源异型C类基因AGAMOUS(AG)决定了生殖器官(雄蕊和心皮)的特性和花分生组织的决定。对其他优树核心种的基因功能分析揭示了该支系中C-谱系的功能保守、亚功能化和功能转换。为了确定AG类基因在二型花(针状花和线状花)的花发育调控中的可能作用和C功能进化，我们从荞麦(荞麦科)中分离并鉴定了AG同源基因，该同源基因是玫瑰-星形分裂之前的核心优树的早期发散物种。蛋白质序列比对和系统发育分析将FesaAG归入euAG谱系。表达分析表明，FAESAG仅在针状花和线状花的雄蕊和雌蕊发育过程中表达。此外，在雄蕊迅速增大和小孢子母细胞减数分裂时，针花和线花中FAESAG的表达均达到较高水平。FAESAG能够替代内源AG基因来确定雄蕊和心皮的特性，并在拟南芥AG-1突变体中实现。异源表达FesAG导致了很早的开花，并产生了畸形的花序和畸形的花，其中萼片转化为心皮，花瓣转化为雄蕊。我们的结果证实了在玫瑰-小行星分裂之前AG同源基因的完整C-功能的建立，尽管核心被子植物的早期和晚期分叉的谱系中存在着不同的花特征。
In the model species Arabidopsis thaliana, the floral homeotic C-class gene AGAMOUS (AG) specifies reproductive organ (stamen and carpels) identity and floral meristem determinacy. Gene function analyses in other core eudicots species reveal functional conservation, subfunctionalization and function switch of the C-lineage in this clade. To identify the possible roles of AG-like genes in regulating floral development in distylous species with dimorphic flowers (pin and thrum) and the C function evolution, we isolated and identified an AG ortholog from Fagopyrum esculentum (buckwheat, Family Polygonaceae), an early diverging species of core eudicots preceding the rosids-asterids split. Protein sequence alignment and phylogenetic analysis grouped FaesAG into the euAG lineage. Expression analysis suggested that FaesAG expressed exclusively in developing stamens and gynoecium of pin and thrum flowers. Moreover, FaesAG expression reached a high level in both pin and thrum flowers at the time when the stamens were undergoing rapidly increased in size and microspore mother cells were in meiosis. FaesAG was able to substitute for the endogenous AG gene in specifying stamen and carpel identity and in an Arabidopsis ag-1 mutant. Ectopic expression of FaesAG led to very early flowering, and produced a misshapen inflorescence and abnormal flowers in which sepals had converted into carpels and petals were converted to stamens. Our results confirmed establishment of the complete C-function of the AG orthologous gene preceding the rosids-asterids split, despite the distinct floral traits present in early- and late-diverging lineages of core eudicot angiosperms.