Transcriptomic Analysis in Strawberry Fruits Reveals Active Auxin Biosynthesis and Signaling in the Ripe Receptacle.
Transcriptomic Analysis in Strawberry Fruits Reveals Active Auxin Biosynthesis and Signaling in the Ripe Receptacle.
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DOI：
10.3389/fpls.2017.00889
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发表时间：
2017
影响因子：
5.6
通讯作者：
Valpuesta V
中科院分区：
文献类型：
--
作者：
Estrada-Johnson E;Csukasi F;Pizarro CM;Vallarino JG;Kiryakova Y;Vioque A;Brumos J;Medina-Escobar N;Botella MA;Alonso JM;Fernie AR;Sánchez-Sevilla JF;Osorio S;Valpuesta V
生长素在成熟草莓（Fragaria ×ananassa）果实中的作用一直被限制在发育的早期阶段，在那里，花托的生长依赖于瘦果的生长素的输送。在稍后阶段，在花托扩大期间，其他激素已被证明不同程度地参与，从赤霉素和脱落酸的普遍参与到更特殊的乙烯。在这里，我们报道了生长素在花托成熟后期的参与。花托的生长素含量在成熟过程中保持不变。通过对草莓果实成熟转录组的分析，揭示了生长素合成、感知、信号转导和转运等基因在瘦果和花托发育过程中由绿向红的表达模式变化。相应基因家族的特定成员在成熟的花托中表现出活跃的转录。对于生长素的合成，编码色氨酸转氨酶的两个基因FaTAA1和FaTAR2在红色受体中表达，其中FaTAR2的表达在这一阶段达到高峰。该基因在成熟受体中的短暂沉默伴随着对生长素的反应减弱。在DR5-GUS转基因草莓植株的成熟花托中，一个GUS报告基因的dr5定向表达支持了生长素在成熟花托中的活性。通过FaAux/IAA和FaARF家族成员的共表达进行聚类，鉴定出5个成员的转录活性随着受体成熟的开始而增加。其中，FaAux/IAA11和FaARF6a从表达水平和折叠变化来看，最有可能参与成熟容器中生长素的活性。拟南芥中相应的ARF6基因与细胞伸长的关联构成了FaARF6a参与生长和成熟容器中相同的细胞过程的推测。
The role of auxin in ripening strawberry (Fragaria ×ananassa) fruits has been restricted to the early stages of development where the growth of the receptacle is dependent on the delivery of auxin from the achenes. At later stages, during enlargement of the receptacle, other hormones have been demonstrated to participate to different degrees, from the general involvement of gibberellins and abscisic acid to the more specific of ethylene. Here we report the involvement of auxin at the late stages of receptacle ripening. The auxin content of the receptacle remains constant during ripening. Analysis of the transcriptome of ripening strawberry fruit revealed the changing expression pattern of the genes of auxin synthesis, perception, signaling and transport along with achene and receptacle development from the green to red stage. Specific members of the corresponding gene families show active transcription in the ripe receptacle. For the synthesis of auxin, two genes encoding tryptophan aminotransferases, FaTAA1 and FaTAR2, were expressed in the red receptacle, with FaTAR2 expression peaking at this stage. Transient silencing of this gene in ripening receptacle was accompanied by a diminished responsiveness to auxin. The auxin activity in the ripening receptacle is supported by the DR5-directed expression of a GUS reporter gene in the ripening receptacle of DR5-GUS transgenic strawberry plants. Clustering by co-expression of members of the FaAux/IAA and FaARF families identified five members whose transcriptional activity was increased with the onset of receptacle ripening. Among these, FaAux/IAA11 and FaARF6a appeared, by their expression level and fold-change, as the most likely candidates for their involvement in the auxin activity in the ripening receptacle. The association of the corresponding ARF6 gene in Arabidopsis to cell elongation constitutes a suggestive hypothesis for FaARF6a involvement in the same cellular process in the growing and ripening receptacle.