Distinctive expression patterns and roles of the miRNA393/TIR1 homolog module in regulating flag leaf inclination and primary and crown root growth in rice (Oryza sativa)
Distinctive expression patterns and roles of the miRNA393/TIR1 homolog module in regulating flag leaf inclination and primary and crown root growth in rice (Oryza sativa)
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DOI：
10.1111/j.1469-8137.2012.04248.x
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发表时间：
2012-10-01
期刊：
影响因子：
9.4
通讯作者：
Zhu, Muyuan
中科院分区：
文献类型：
--
作者：
Bian, Hongwu;Xie, Yakun;Zhu, Muyuan
MicroRNA (miRNA) 介导的生长素信号成分调节在植物发育中发挥着关键作用。 miRNA 表达和功能多样性导致 miRNA/靶标模块调控网络的复杂性。本研究对水稻 (Oryza sativa) miR393 家族的两个成员及其靶基因 OsTIR1 和 OsAFB2 (AUXIN SIGNALING F-BOX) 进行了功能表征，这是拟南芥转运抑制物响应 1 (TIR1) 的两个最接近的同源物。 我们发现miR393家族成员具有独特的表达模式，miR393a主要在冠和侧根原基以及胚芽鞘尖端表达，而miR393b在茎尖分生组织中表达。过表达 miR393a/b 的转基因植物表现出严重的表型，具有生长素信号传导改变的特征，主要包括旗叶倾斜度增大以及初生根和冠根生长改变。此外，OsAFB2 和 OsTIR1 抑制品系在孕穗期表现出旗叶倾斜度增加，类似于 miR393 过表达植物。此外，酵母双杂交和双分子荧光互补实验表明OsTIR1和OsAFB2与OsIAA1相互作用。miRNA393的表达多样化暗示了miRNA在物种进化过程中调控的潜在作用。 miR393/靶标模块的保守机制表明miR393介导的水稻生长素信号转导调节的根本重要性。
MicroRNA (miRNA)-mediated regulation of auxin signaling components plays a critical role in plant development. miRNA expression and functional diversity contribute to the complexity of regulatory networks of miRNA/target modules.This study functionally characterizes two members of the rice (Oryza sativa) miR393 family and their target genes, OsTIR1 and OsAFB2 (AUXIN SIGNALING F-BOX), the two closest homologs of Arabidopsis TRANSPORT INHIBITOR RESPONSE 1 (TIR1). We found that the miR393 family members possess distinctive expression patterns, with miR393a expressed mainly in the crown and lateral root primordia, as well as the coleoptile tip, and miR393b expressed in the shoot apical meristem. Transgenic plants overexpressing miR393a/b displayed a severe phenotype with hallmarks of altered auxin signaling, mainly including enlarged flag leaf inclination and altered primary and crown root growth. Furthermore, OsAFB2- and OsTIR1-suppressed lines exhibited increased inclination of flag leaves at the booting stage, resembling miR393-overexpressing plants. Moreover, yeast two-hybrid and bimolecular fluorescence complementation assays showed that OsTIR1 and OsAFB2 interact with OsIAA1.Expression diversification of miRNA393 implies the potential role of miRNA regulation during species evolution. The conserved mechanisms of the miR393/target module indicate the fundamental importance of the miR393-mediated regulation of auxin signal transduction in rice.