背景回顾：Light induces anthocyanin accumulation and hence decides the coloration of apple fruit. It also plays a key role in regulating the biosynthesis of other secondary metabolites. 

提出问题：However, the crosstalk between anthocyanin and lignin metabolism during light induction, which affects the edible quality and visual quality of apple fruit, respectively, have rarely been characterized. 

主要研究：In this study, we identified and functionally elucidated the roles of miR7125 and its target, cinnamoyl‐coenzyme A reductase gene (CCR), in regulating the homeostasis between anthocyanin and lignin biosynthesis during light induction. 

结果1-miR7125过表达和CCR抑制：Overexpressing miR7125 or inhibiting CCR transiently in apple fruit promoted anthocyanin biosynthesis but reduced lignin production under light‐induced conditions. 

结果2-miR7125抑制和CCR过表达：Consistently, opposite results were observed under the background of repressed miR7125 or overexpressed CCR. 

结果3-上游调控子MdMYB16/MdMYB1：We found that the repressor MdMYB16 and the activator MdMYB1 bound to the miR7125 promoter. 

结果4-MdMYB16/MdMYB1验证：Transient repression of MdMYB16 upregulated miR7125 expression significantly, accompanied by decreased levels of MdCCR transcript, resulting in a reduction in the lignin biosynthesis and an increase in anthocyanin accumulation. However, transient overexpression of MdMYB16 produced the opposite effects to MdMYB16‐RNAi. 

结论：The results reveal a novel mechanism by which the MdMYB16/MdMYB1‐miR7125‐MdCCR module collaboratively regulates homeostasis between anthocyanin and lignin biosynthesis under light induction in apple.

 摘 要 

光诱导花色苷积累，从而决定了苹果果实的着色。同时，光还在其它次生代谢物的生物合成调控中发挥关键作用。花色苷与木质素是影响苹果外观品质和食用品质的关键次生代谢物 ，但是光诱导过程中花色苷与木质素代谢的交联机制并不清楚。本文中，作者鉴定了miR7125及其靶基因肉桂酰辅酶A还原酶基因CCR在光诱导过程中，花色苷与木质素生物合成动态平衡的调控作用。在苹果果实中，瞬间过表达miR7125基因或者抑制CCR基因均能够促进光照条件下的花色苷生物合成，但是会减少木质素的产量。与此一致的是，在miR7125抑制或者CCR过表达株系中，作者观察到了相反的表型。作者发现抑制子MdMYB16和激活子MdMYB1能够结合到的miR7125启动子区。瞬间抑制MdMYB16能够显著上调miR7125的表达，并且伴随着MdCCR转录本水平的降低，导致了木质素生物合成减少，而花色苷生物合成增加。MdMYB16基因的瞬间过表达产生了与MdMYB16‐RNAi株系相反的效应。本文的结果揭示了一个调控苹果在光诱导下花色苷与木质素动态平衡的分子调控模块MdMYB16/MdMYB1‐miR7125‐MdCCR。