The RAV (related to ABI3/viviparous 1) group of transcription factors (TFs) play multifaceted roles in plant development and stress responses. Here, we show that strawberry (Fragaria × ananassa) FaRAV1 positively regulates anthocyanin accumulation during fruit ripening via a hierarchy of activation processes. Dual‐luciferase assay screening of all fruit‐expressed AP2/ERFs showed FaRAV1 had the highest transcriptional activation of the promoter of FaMYB10, a key activator of anthocyanin biosynthesis. Yeast one‐hybrid and electrophoretic mobility shift assays indicated that FaRAV1 could directly bind to the promoter of FaMYB10. Transient overexpression of FaRAV1 in strawberry fruit increased FaMYB10 expression and anthocyanin production significantly. Correspondingly, transient RNA interference‐induced silencing of FaRAV1 led to decreases in FaMYB10 expression and anthocyanin content. Transcriptome analysis of FaRAV1‐overexpressing strawberry fruit revealed that transcripts of phenylpropanoid and flavonoid biosynthesis pathway genes were up‐regulated. Luciferase assays showed that FaRAV1 could also activate the promoters of strawberry anthocyanin biosynthetic genes directly, revealing a second level of FaRAV1 action in promoting anthocyanin accumulation. These results show that FaRAV1 stimulates anthocyanin accumulation in strawberry both by direct activation of anthocyanin pathway gene promoters and by up‐regulation of FaMYB10, which also positively regulates these genes.

中文翻译：

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草莓转录因子FaRAV1通过激活FaMYB10和花青素途径基因来正调节花青素的积累

RAV（与ABI3 / viviparous 1有关）组的转录因子（TFs）在植物发育和胁迫响应中起着多方面的作用。在这里，我们显示草莓（Fragaria  ×  ananassa）FaRAV1通过激活过程的层次结构正调控果实成熟过程中的花色苷积累。对所有水果表达的AP2 / ERF进行双荧光素酶分析筛选显示，FaRAV1的花青素生物合成关键激活因子FaMYB10启动子的转录激活最高。酵母单杂交和电泳迁移率迁移分析表明FaRAV1可以直接结合FaMYB10的启动子。FaRAV1的瞬时过表达草莓果实中的FacYB10表达和花青素产量显着增加。相应地，瞬时RNA干扰诱导的FaRAV1沉默导致FaMYB10表达和花色苷含量降低。FaraV1过表达草莓果实的转录组分析显示，苯丙烷和类黄酮生物合成途径基因的转录本上调。萤光素酶分析表明，FaRAV1还可以直接激活草莓花色苷生物合成基因的启动子，从而揭示FaRAV1在促进花色苷积累方面的第二个作用水平。这些结果表明FaRAV1通过直接激活花青素途径基因启动子和上调FaMYB10来刺激草莓中花青素的积累，而FaMYB10也正调控这些基因。