类黄酮是苹果营养品质的重要构成因素，对人体健康具有重要作用。培育高类黄酮含量的特色多样化品种是苹果产业的重要需求。在苹果类黄酮合成及代谢过程中，除了广泛研究的转录调控外，miRNAs介导的转录后调控也得到越来越多的关注。为探究miRNAs调控苹果果实类黄酮合成的分子机制，本申请以不同类黄酮含量的红肉苹果为试材进行小RNA测序，筛选获得了一个差异表达的miR858；通过与靶基因的碱基互补配对及qRT-PCR分析，预测miR858可能靶定类黄酮合成相关的MYB转录因子MdMYB5/12/114/308。在此基础上，本申请拟进一步通过5’RACE实验、LUC报告实验、GUS活性分析等技术，结合转基因功能验证，研究miR858通过介导MdMYB5/12/114/308从而参与类黄酮合成的分子机理，为丰富miRNAs调控类黄酮代谢的理论体系提供基本资料，也为高类黄酮苹果育种和品质改良提供科学依据。

Flavonoid is an important component of apple nutritional quality and plays an important role in human health. In the process of flavonoid synthesis and metabolism in apple, in addition to extensive research on transcriptional regulation, post-transcriptional regulation mediated by miRNAs has also attracted more and more attention. To explore the molecular mechanism of miRNAs regulating the synthesis of flavonoid in apple fruits, red-fleshed apple with different flavonoid content was used as test material for miRNAs sequencing, and a differentially expressed miRNA named miR858 was screened. It is predicted that miR858 is likely to target the MYB transcription factor MdMYB5/12/114/308 related to flavonoid synthesis by base complementary pairing and qRT-PCR experiments. On this basis, this application intends to study the molecular mechanism of miR858 in flavonoid synthesis by targeting MdMYB5/12/114/308 through molecular biology techniques such as 5’RACE, GUS activity test, luciferase report assay, combined with the transgenic verification. This will provide basic information for enriching the theoretical system of plant miRNAs regulation of flavonoid metabolism, as well as scientific basis for high flavonoid apple breeding and quality improvement.