College of Agriculture and Biotechnology, Zhejiang University, Hangzhou, China.
Zhejiang Provincial Key Laboratory of Horticultural Plant Integrative Biology, Zhejiang University, Hangzhou, China.
Plant Biotechnol J. 2020 Nov;18(11):2267-2279. doi: 10.1111/pbi.13382. Epub 2020 Apr 13.
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.
RAV(与 ABI3/viviparous 1 有关)转录因子(TFs)家族在植物发育和应激反应中发挥着多方面的作用。在这里,我们表明草莓( Fragaria ×ananassa )FaRAV1 通过一系列激活过程正向调控果实成熟过程中的花青素积累。对所有果实表达的 AP2/ERF 的双荧光素酶报告基因筛选表明,FaRAV1 对花青素生物合成关键激活因子 FaMYB10 的启动子具有最高的转录激活活性。酵母单杂交和电泳迁移率变动分析表明,FaRAV1 可以直接结合 FaMYB10 的启动子。瞬时过表达 FaRAV1 在草莓果实中显著增加了 FaMYB10 的表达和花青素的产生。相应地,瞬时 RNA 干扰诱导的 FaRAV1 沉默导致 FaMYB10 的表达和花青素含量降低。FaRAV1 过表达草莓果实的转录组分析表明,苯丙烷和类黄酮生物合成途径基因的转录本上调。荧光素酶报告基因检测表明,FaRAV1 还可以直接激活草莓花青素生物合成基因的启动子,揭示了 FaRAV1 促进花青素积累的第二个作用层次。这些结果表明,FaRAV1 通过直接激活花青素途径基因的启动子和上调 FaMYB10 来刺激草莓中花青素的积累,FaMYB10 也正向调控这些基因。