FtMYB8 from Tartary buckwheat inhibits both anthocyanin/Proanthocyanidin accumulation and marginal Trichome initiation
FtMYB8 from Tartary buckwheat inhibits both anthocyanin/Proanthocyanidin accumulation and marginal Trichome initiation
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DOI：
10.1186/s12870-019-1876-x
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发表时间：
2019-06-18
影响因子：
5.3
通讯作者：
Zhao, Haixia
中科院分区：
文献类型：
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作者：
Huang, Yunji;Wu, Qi;Zhao, Haixia
背景由于类黄酮和毛状体在植物防御中起着至关重要的作用，它们的形成需要多个转录因子家族的精细转录调控。然而，R2R3-MYB转录因子同时调节类黄酮类代谢和毛状体发育的机制还知之甚少。结果我们从苦荞麦FtMYB8中鉴定出一个独特的SG4-like-MYB Tf，它含有C2抑制基序和一个额外的TLLLFR抑制基序。FtMYB8基因的表达谱结合P-FtMYB8启动子的转录活性表明，FtMYB8基因主要在真叶期和开花期的根中积累，并在芽毛和花中积累，该基因的表达受到MeJA、ABA和UV-B处理的显著诱导，但受到黑暗处理的抑制。在拟南芥中过表达FtMYB8通过特异性抑制TT12的表达来减少花青素/原花青素的积累，这可能依赖于FtMYB8和TT8之间的相互作用。结论综合考虑，FtMYB8可能通过平衡转录激活剂的诱导效应，微调苦荞根和花中花青素/原花青素的积累，并可能调节苦荞芽中毛状体的分布。
BackgroundBecause flavonoids and trichomes play crucial roles in plant defence, their formation requires fine transcriptional control by multiple transcription factor families. However, little is known regarding the mechanism of the R2R3-MYB transcription factors that regulate both flavonoid metabolism and trichome development.ResultsHere, we identified a unique SG4-like-MYB TF from Tartary buckwheat, FtMYB8, which harbours the C2 repression motif and an additional TLLLFR repression motif. The expression profiles of FtMYB8 combined with the transcriptional activity of P-FtMYB8 promoter showed that FtMYB8 mRNA mainly accumulated in roots during the true leaf stage and flowering stage and in bud trichomes and flowers, and the expression of this gene was markedly induced by MeJA, ABA and UV-B treatments but repressed by dark treatment. Overexpression of FtMYB8 in Arabidopsis reduces the accumulation of anthocyanin/proanthocyanidin by specifically inhibiting TT12 expression, which may depend on the interaction between FtMYB8 and TT8. Interestingly, this interaction may also negatively regulate the marginal trichome initiation in Arabidopsis leaves.ConclusionsTaken together, our results suggest that FtMYB8 may fine-tune the accumulation of anthocyanin/proanthocyanidin in the roots and flowers of Tartary buckwheat by balancing the inductive effects of transcriptional activators, and probably regulate trichome distribution in the buds of Tartary buckwheat.