Developmental Functions of miR156-Regulated SQUAMOSA PROMOTER BINDING PROTEIN-LIKE (SPL) Genes in Arabidopsis thaliana.
Developmental Functions of miR156-Regulated SQUAMOSA PROMOTER BINDING PROTEIN-LIKE (SPL) Genes in Arabidopsis thaliana.
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DOI：
10.1371/journal.pgen.1006263
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发表时间：
2016-08
期刊：
影响因子：
4.5
通讯作者：
Poethig RS
中科院分区：
文献类型：
--
作者：
Xu M;Hu T;Zhao J;Park MY;Earley KW;Wu G;Yang L;Poethig RS
正确的发育时间对植物适应性和繁殖成功至关重要。SQUAMOSA启动子结合蛋白（SBP）基因miR156介导了幼芽发育的两个重要转变——从幼芽到成虫的营养转变和从营养到生殖的转变。为了确定这些基因在拟南芥中的发育功能，我们表征了它们的表达模式，以及它们的功能获得和功能丧失表型。结果表明，拟南芥中SBP-LIKE （SPL）基因在功能上可分为3个不同的类群：1)SPL2、SPL9、SPL10、SPL11、SPL13和SPL15参与了从幼体到成体的营养转变和从营养到生殖的转变，其中SPL9、SP13和SPL15在这些过程中比SPL2、SPL10和SPL11更重要；2) SPL3、SPL4和SPL5在营养相变和成花诱导中不起主要作用，但促进花分生组织身份的转变；3) SPL6在茎部形态发生中不起主要作用，但可能在某些生理过程中起重要作用。我们还发现mir156调控的SPL基因抑制不定根的发育，这就解释了随着茎龄的增长不定根产生能力下降的现象。miR156在幼苗中表达水平非常高，并随着茎的发育而下降。它完全阻断其SPL靶基因在莲座头两叶的表达，并在发育后期不同程度地抑制这些基因，主要是通过促进它们的翻译抑制。这些结果为未来研究这一多功能转录因子家族提供了框架，并为miR156在拟南芥发育中的作用提供了新的见解。在拟南芥中，miR156通过抑制10个SQUAMOSA启动子结合蛋白样（SPL）基因的表达而起作用。植物过表达miR156的表型表明，这些基因控制着植物发育和生理的许多方面，但miR156调控的单个SPL基因的功能以及它们的表达如何受到miR156的调控，在很大程度上是未知的。我们通过确定这些基因中单个和组合的功能丧失突变的表型，并通过比较这些基因的mir156敏感和mir156抗性报告的表达模式和表型来解决这些问题。我们的研究结果揭示了该基因家族成员的独特和共享功能，并证明miR156在发育的不同时期对SPL基因表达的调控作用不同。
Correct developmental timing is essential for plant fitness and reproductive success. Two important transitions in shoot development—the juvenile-to-adult vegetative transition and the vegetative-to-reproductive transition—are mediated by a group of genes targeted by miR156, SQUAMOSA PROMOTER BINDING PROTEIN (SBP) genes. To determine the developmental functions of these genes in Arabidopsis thaliana, we characterized their expression patterns, and their gain-of-function and loss-of-function phenotypes. Our results reveal that SBP-LIKE (SPL) genes in Arabidopsis can be divided into three functionally distinct groups: 1) SPL2, SPL9, SPL10, SPL11, SPL13 and SPL15 contribute to both the juvenile-to-adult vegetative transition and the vegetative-to-reproductive transition, with SPL9, SP13 and SPL15 being more important for these processes than SPL2, SPL10 and SPL11; 2) SPL3, SPL4 and SPL5 do not play a major role in vegetative phase change or floral induction, but promote the floral meristem identity transition; 3) SPL6 does not have a major function in shoot morphogenesis, but may be important for certain physiological processes. We also found that miR156-regulated SPL genes repress adventitious root development, providing an explanation for the observation that the capacity for adventitious root production declines as the shoot ages. miR156 is expressed at very high levels in young seedlings, and declines in abundance as the shoot develops. It completely blocks the expression of its SPL targets in the first two leaves of the rosette, and represses these genes to different degrees at later stages of development, primarily by promoting their translational repression. These results provide a framework for future studies of this multifunctional family of transcription factors, and offer new insights into the role of miR156 in Arabidopsis development. In Arabidopsis, miR156 acts by repressing the expression of 10 SQUAMOSA PROMOTOR BINDING PROTEIN-LIKE (SPL) genes. The phenotype of plants over-expressing miR156 demonstrates that these genes control many aspects of plant development and physiology, but the functions of individual miR156-regulated SPL genes, and how their expression is regulated by miR156, are largely unknown. We addressed these questions by determining the phenotypes of loss-of-function mutations in these genes individually and in combination, and by comparing the expression patterns and the phenotypes of miR156-sensitive and miR156-resistant reporters for these genes. Our results reveal the unique and shared functions of the members of this gene family, and demonstrate that miR156 plays different roles in the regulation of SPL gene expression at different times in development.