A single amino acid substitution in the R2R3 conserved domain of the BrPAP1a transcription factor impairs anthocyanin production in turnip (Brassica rapa subsp. rapa).
A single amino acid substitution in the R2R3 conserved domain of the BrPAP1a transcription factor impairs anthocyanin production in turnip (Brassica rapa subsp. rapa).
复制标题
DOI：
10.1016/j.plaphy.2021.02.011
复制
发表时间：
2021-02
期刊：
影响因子：
--
通讯作者：
Jianfei Yang;Hyon Dok Song;Yunzhu Chen;Bowei Chen;Min-Jun Kim;Pyol Kim;S. Kawabata;Yuhua Li;Yu Wang
中科院分区：
文献类型：
--
作者：
Jianfei Yang;Hyon Dok Song;Yunzhu Chen;Bowei Chen;Min-Jun Kim;Pyol Kim;S. Kawabata;Yuhua Li;Yu Wang
光诱导津田芜菁（Brassica rapasubsp.rapa）膨大根表皮紫色色素形成，为研究光依赖型芜菁花色素苷生物合成的遗传机制提供了良好的体系。在此，我们鉴定了R2 R3 MYB转录因子基因花青素色素的产生1（BrPAP 1a）作为花青素苷缺陷型突变体tw 68中的关键基因。在R3结构域的转角区域中的核苷酸突变被筛选，其导致从甘氨酸到丝氨酸的氨基酸取代（G94 S）。功能分析表明，BrPAP 1a与两个bHLH因子Glabra增强子3（BrEGL 3）和透明睾丸8（BrTT 8）的相互作用因突变而受损。BrTT 8的表达被BrPAP 1a激活，并被MYB-bHLH-WDR（MBW）复合物增强，但被突变阻断。此外，BrPAP 1a直接结合BrTT 8启动子中的MYB识别元件（MRE），而G94 S取代导致DNA结合活性丧失。我们的研究结果表明，G94是必需的蛋白质相互作用与BrTT 8和BrEGL 3和DNA结合的BrPAP 1a激活BrTT 8的表达，这导致花青素的生物合成。总的来说，我们的数据表明R2 R3 MYB蛋白中高度保守的氨基酸在调节花青素苷生物合成中的重要性，并且可以帮助增加芜菁根中花青素苷的程序。
The purple pigmentation in the epidermis of swollen roots of ‘Tsuda’ turnip (Brassica rapasubsp.rapa) is induced by light, providing a good system to investigate the genetic mechanism of light-dependent anthocyanin biosynthesis inB. rapa.Here, we identified the R2R3 MYB transcription factor gene PRODUCTION OF ANTHOCYANIN PIGMENT1 (BrPAP1a) as the critical gene in the anthocyanin-defective mutantw68. A nucleotide mutation in the turn region of the R3 domain was screened, which caused an amino acid substitution from glycine to serine (G94S). Functional analysis showed that the interaction of BrPAP1a with two bHLH factors ENHANCER OF GLABRA 3 (BrEGL3) and TRANSPARENT TESTA 8 (BrTT8) were impaired by the mutation. Expression ofBrTT8was activated by BrPAP1a and enhanced by MYB-bHLH-WDR (MBW) complexes, but blocked by the mutation. Furthermore, BrPAP1a directly bound the MYB-recognizing element (MRE) in theBrTT8promoter, while the G94S substitution caused a loss of DNA-binding activity. Our findings indicate that G94 is required for protein interaction with BrTT8 and BrEGL3 and DNA-binding of BrPAP1a to activateBrTT8expression, which leads to anthocyanin biosynthesis. Collectively, our data indicate the importance of the highly conserved amino acids within R2R3 MYB proteins in regulating anthocyanin biosynthesis and could aid programs to increase anthocyanins in turnip roots.