Many LACs are regulated by copper-miRNAs (Cu-miRNAs), which target genes encoding copper-containing proteins. LACs are required for lignification and flavonoid synthesis in plants and have been associated with plant development and stress tolerance. So, the researchers investigated the effects on stress tolerance of manipulating Cu-miRNAs. Specifically, they chose three Cu-miRNAs (miR397, miR408 and miR528), as these three collectively target 18 out of the 28 LAC family genes in rice. Simultaneously overexpressing the three Cu-miRNAs in rice (3miR-OE) caused extensive silencing of LACs, reducing both laccase activity and lignin content, whereas knocking out the three miRNAs generated the opposite phenotype.

The transcriptome of 3miR-OE plants showed changes in the expression of genes encoding laccases, peroxidases, and elements of the phenylpropanoid metabolic and flavonoid biosynthetic pathways. The metabolome of 3miR-OE plants showed a reduction in products of the lignin pathway but dramatically increased flavonoid metabolites. So, overexpressing the three miRNAs diverts metabolism from lignin synthesis to flavonoid accumulation in rice.

许多 LAC 受铜 miRNA （Cu-miRNA） 的调节，铜 miRNA （Cu-miRNA） 靶向编码含铜蛋白的基因。LACs 是植物木质化和类黄酮合成所必需的，并且与植物发育和抗逆性有关。因此，研究人员研究了操作 Cu-miRNA 对压力耐受性的影响。具体来说，他们选择了三个 Cu-miRNA （miR397、miR408 和 miR528），因为这三个基因共同靶向水稻中 28 个 LAC 家族基因中的 18 个。在水稻中同时过表达 3 个 Cu-miRNA （3miR-OE） 导致 LACs 的广泛沉默，降低漆酶活性和木质素含量，而敲除 3 个 miRNA 产生相反的表型。

3miR-OE 植物的转录组显示编码漆酶、过氧化物酶的基因表达以及苯丙烷类代谢和类黄酮生物合成途径元件的变化。3miR-OE 植物的代谢组显示木质素途径的产物减少，但类黄酮代谢物显着增加。因此，过表达这三种 miRNA 将代谢从木质素合成转移到水稻中的类黄酮积累。