Tropical Crops Genetic Resources Institute, The Chinese Academy of Tropical Agricultural Sciences (CATAS)/Key Laboratory of Crop Gene Resources and Germplasm Enhancement in Southern China, Ministry of Agriculture, Danzhou, 571737, China.
The Engineering Technology Research Center of Tropical Ornamental Plant Germplasm Innovation and Utilization, Danzhou, 571737, Hainan Province, China.
Plant Cell Rep. 2016 Oct;35(10):2151-65. doi: 10.1007/s00299-016-2025-8. Epub 2016 Jul 16.
A R2R3-MYB gene AaMYB2 was isolated from Anthurium andraeanum (Hort.) and was functionally characterized to be a positive transcriptional regulator for anthocyanin biosynthesis in the spathes and leaves. Spathe coloration is an important Anthurium andraeanum (Hort.) characteristic, which is mainly contributed by anthocyanins. R2R3-MYB transcription factors (TFs) are important regulators of anthocyanin biosynthesis in plants. Here we describe the identification and characterization of AaMYB2, a member in subgroup 6 of the R2R3-MYB TFs family, which correlated with anthocyanin biosynthesis in A. andraeanum. AaMYB2 was a nuclear-localization protein with positive transcriptional activity, and prominently expressed in the red spathes. Ectopic expression of AaMYB2 in tobacco led to anthocyanin accumulation and up-regulation of the early and late anthocyanin pathway genes, particularly NtDFR, NtANS, and NtUFGT, and the endogenous TF genes NtAn2 and NtAn1 in leaves. In the developing red spathes of 'Tropical' and 'Vitara', the expression of AaMYB2 was closely linked to anthocyanin accumulation, and co-expressed with AaCHS, AaF3H, and AaANS, the latter two of which were regarded as the potential targets of the R locus encoding a TF controlling spathe colors inheritance in anthurium. In addition, the transcription level of AaMYB2 in various cultivars with different color phenotypes showed that AaMYB2 was drastically expressed in the spathes from the red, pink, and purple cultivars, but hardly detected in the spathes from the white and green ones. Besides, AaMYB2 also showed higher expression in newly developmental leaves when anthocyanin was actively biosynthesized. Taken together, AaMYB2 positively related to anthocyanin biosynthesis in anthurium spathes and leaves, and appeared to regulate the expression of AaF3H, AaANS, and possibly AaCHS.
从安祖花（Hort.）中分离出一个 R2R3-MYB 基因 AaMYB2，并对其功能进行了表征，结果表明该基因是花葶和叶片中花色苷生物合成的正转录调控因子。花葶颜色是安祖花（Hort.）的一个重要特征，主要由花色苷贡献。R2R3-MYB 转录因子（TFs）是植物花色苷生物合成的重要调控因子。在这里，我们描述了 AaMYB2 的鉴定和表征，它是 R2R3-MYB TF 家族亚组 6 的成员，与安祖花中的花色苷生物合成相关。AaMYB2 是一种核定位蛋白，具有正转录活性，在红色花葶中表达明显。在烟草中异位表达 AaMYB2 导致花色苷积累，并上调早期和晚期花色苷途径基因，特别是 NtDFR、NtANS 和 NtUFGT，以及叶片中的内源性 TF 基因 NtAn2 和 NtAn1。在 'Tropical' 和 'Vitara' 的发育中的红色花葶中，AaMYB2 的表达与花色苷积累密切相关，与 AaCHS、AaF3H 和 AaANS 共同表达，后两者被认为是 R 基因座编码的 TF 的潜在靶标，该 TF 控制安祖花花葶颜色的遗传。此外，不同颜色表型品种的 AaMYB2 转录水平表明，AaMYB2 在红色、粉色和紫色品种的花葶中表达强烈，但在白色和绿色品种的花葶中几乎检测不到。此外，当花色苷积极合成时，AaMYB2 在新发育的叶片中也表现出较高的表达。综上所述，AaMYB2 与安祖花花葶和叶片中的花色苷生物合成呈正相关，似乎调节 AaF3H、AaANS 的表达，可能还调节 AaCHS 的表达。
