Lotkowska Magda E, Tohge Takayuki, Fernie Alisdair R, Xue Gang-Ping, Balazadeh Salma, Mueller-Roeber Bernd
Institute of Biochemistry and Biology, University of Potsdam, D-14476 Potsdam-Golm, Germany (M.E.L., S.B., B.M.-R.);Central Metabolism (T.T., A.R.F.) andPlant Signaling (S.B., B.M.-R.) Groups, Max-Planck Institute of Molecular Plant Physiology, D-14476 Potsdam-Golm, Germany; andCSIRO Agriculture Flagship, Brisbane, Queensland 4067, Australia (G.-P.X.).
Institute of Biochemistry and Biology, University of Potsdam, D-14476 Potsdam-Golm, Germany (M.E.L., S.B., B.M.-R.);Central Metabolism (T.T., A.R.F.) andPlant Signaling (S.B., B.M.-R.) Groups, Max-Planck Institute of Molecular Plant Physiology, D-14476 Potsdam-Golm, Germany; andCSIRO Agriculture Flagship, Brisbane, Queensland 4067, Australia (G.-P.X.)
Plant Physiol. 2015 Nov;169(3):1862-80. doi: 10.1104/pp.15.00605. Epub 2015 Sep 16.
MYB transcription factors (TFs) are important regulators of flavonoid biosynthesis in plants. Here, we report MYB112 as a formerly unknown regulator of anthocyanin accumulation in Arabidopsis (Arabidopsis thaliana). Expression profiling after chemically induced overexpression of MYB112 identified 28 up- and 28 down-regulated genes 5 h after inducer treatment, including MYB7 and MYB32, which are both induced. In addition, upon extended induction, MYB112 also positively affects the expression of PRODUCTION OF ANTHOCYANIN PIGMENT1, a key TF of anthocyanin biosynthesis, but acts negatively toward MYB12 and MYB111, which both control flavonol biosynthesis. MYB112 binds to an 8-bp DNA fragment containing the core sequence (A/T/G)(A/C)CC(A/T)(A/G/T)(A/C)(T/C). By electrophoretic mobility shift assay and chromatin immunoprecipitation coupled to quantitative polymerase chain reaction, we show that MYB112 binds in vitro and in vivo to MYB7 and MYB32 promoters, revealing them as direct downstream target genes. We further show that MYB112 expression is up-regulated by salinity and high light stress, environmental parameters that both require the MYB112 TF for anthocyanin accumulation under these stresses. In contrast to several other MYB TFs affecting anthocyanin biosynthesis, MYB112 expression is not controlled by nitrogen limitation or an excess of carbon. Thus, MYB112 constitutes a regulator that promotes anthocyanin accumulation under abiotic stress conditions.
MYB转录因子(TFs)是植物类黄酮生物合成的重要调节因子。在此,我们报道MYB112是拟南芥中一个此前未知的花青素积累调节因子。化学诱导过表达MYB112后的表达谱分析确定,在诱导剂处理5小时后有28个上调基因和28个下调基因,包括均被诱导的MYB7和MYB32。此外,延长诱导后,MYB112也正向影响花青素生物合成关键TF花青素色素合成1的表达,但对控制黄酮醇生物合成的MYB12和MYB111起负向作用。MYB112与一个包含核心序列(A/T/G)(A/C)CC(A/T)(A/G/T)(A/C)(T/C)的8碱基对DNA片段结合。通过电泳迁移率变动分析以及与定量聚合酶链反应偶联的染色质免疫沉淀,我们表明MYB112在体外和体内均与MYB7和MYB32启动子结合,揭示它们为直接的下游靶基因。我们进一步表明,盐度和高光胁迫上调MYB112的表达,在这些胁迫下花青素积累均需要MYB112 TF。与其他几个影响花青素生物合成的MYB TF不同,MYB112的表达不受氮限制或碳过量的控制。因此,MYB112构成了一种在非生物胁迫条件下促进花青素积累的调节因子。