背景回顾：A long-standing question in plant biology is how the acquisition of reproductive competence is related to the juvenile-to-adult vegetative transition. 

主要研究：We addressed this question by examining the expression pattern and mutant phenotypes of two families of miRNAs—miR156/miR157 and miR172—that operate in the same pathway and play important roles in these processes. 

结果1-mi172和miR156/157的特定功能：The phenotype of mutants deficient for miR156/miR157, miR172, and all three miRNAs demonstrated that miR156/miR157 regulate the timing of vegetative phase change but have only a minor effect on reproductive competence, whereas miR172 has a minor role in vegetative phase change but has a major effect on reproductive competence. 

结果2-miR172与miR156之间相互独立：MIR172B is directly downstream of the miR156/SPL module, but temporal variation in the level of miR156 in the shoot apex and leaf-to-leaf variation in miR156 expression in young primordia was not associated with a change in the level of miR172 in these tissues.  Additionally, although miR172 levels increase from leaf to leaf later in leaf development, this variation is largely insensitive to changes in the abundance of miR156. 

结论：Our results indicate that the acquisition of reproductive competence in Arabidopsis is regulated by miR172 through a mechanism that is independent of the vegetative phase change pathway.

miR156独立于miR172调控营养生长性状

植物生物学其中一个长期存在的问题就是生殖能力的获取与营养生长期幼成年转变是如何关联的。作者通过对两个在同一通路介导生殖能力获取和营养生长期幼成年转变的miRNAs家族，即miR156/miR157和miR172的表达模式和突变体表型研究了这一问题。miR156/miR157、miR172或3个miRNAs都功能缺失的突变体表型表明，miR156/miR157调控营养生长期变化的时间，但是对于生殖能力的影响较小；而miR172是生殖能力的主要影响因素，反而对营养生长期变化影响较小。MIR172B基因是miR156/SPL模块的直接下游，但是茎尖中miR156水平的时间变化和幼嫩原基中miR156表达的叶片间变异与这些组织中miR172的水平变化并不相关。另外，尽管miR172在叶片中呈现出随着叶片发育增加的趋势，但是这一变化对于miR156的丰度改变并不敏感。综上，本文的研究结果显示拟南芥中生殖能力的获取受到miR172的调控，并且是通过一个独立于营养生长期变化途径的机制。

** R. Scott Poethig **