Dasgupta Kasturi, Thilmony Roger, Stover Ed, Oliveira Maria Luiza, Thomson James
a Department of Plant Sciences , UC Davis , Davis , CA , USA.
b Crop Improvement and Genetics Research Unit , Western Regional Research Center, USDA-ARS , Albany , CA , USA.
GM Crops Food. 2017 Apr 3;8(2):85-105. doi: 10.1080/21645698.2016.1267897. Epub 2017 Jan 4.
The level of anthocyanins in plants vary widely among cultivars, developmental stages and environmental stimuli. Previous studies have reported that the expression of various MYBs regulate anthocyanin pigmentation during growth and development. Here we examine the activity of 3 novel R2R3-MYB transcription factor (TF) genes, PamMybA.1, PamMybA.3 and PamMybA.5 from Prunus americana. The anthocyanin accumulation patterns mediated by CaMV double35S promoter (db35Sp) controlled expression of the TFs in transgenic tobacco were compared with citrus-MoroMybA, Arabidopsis-AtMybA1 and grapevine-VvMybA1 transgenics during their entire growth cycles. The db35Sp-PamMybA.1 and db35Sp-PamMybA.5 constructs induced high levels of anthocyanin accumulation in both transformed tobacco calli and the regenerated plants. The red/purple color pigmentation induced in the PamMybA.1 and PamMybA.5 lines was not uniformly distributed, but appeared as patches in the leaves, whereas the flowers showed intense uniform pigmentation similar to the VvMybA1 expressing lines. MoroMybA and AtMybA1 showed more uniform pink coloration in both vegetative and reproductive tissues. Plant morphology, anthocyanin content, seed viability, and transgene inheritance were examined for the PamMybA.5 transgenic plants and compared with the controls. We conclude that these TFs alone are sufficient for activating anthocyanin production in plants and may be used as visible reporter genes for plant transformation. Evaluating these TFs in a heterologous crop species such as citrus further validated that these genes can be useful for the metabolic engineering of anthocyanin production and cultivar enhancement.
植物中花青素的含量在不同品种、发育阶段和环境刺激下差异很大。先前的研究报道，各种MYB的表达在生长发育过程中调节花青素的色素沉着。在此，我们研究了来自美国李的3个新的R2R3-MYB转录因子（TF）基因PamMybA.1、PamMybA.3和PamMybA.5的活性。在转基因烟草的整个生长周期中，将由CaMV双35S启动子（db35Sp）控制的TFs表达介导的花青素积累模式与柑橘-MoroMybA、拟南芥-AtMybA1和葡萄-VvMybA1转基因植物进行了比较。db35Sp-PamMybA.1和db35Sp-PamMybA.5构建体在转化的烟草愈伤组织和再生植株中均诱导了高水平的花青素积累。PamMybA.1和PamMybA.5株系中诱导的红/紫色色素沉着分布不均匀，在叶片中呈斑块状，而花朵则表现出与表达VvMybA1的株系相似的强烈均匀色素沉着。MoroMybA和AtMybA1在营养组织和生殖组织中均表现出更均匀的粉红色。对PamMybA.5转基因植物的植物形态、花青素含量、种子活力和转基因遗传进行了检测，并与对照进行了比较。我们得出结论，这些TFs单独就足以激活植物中花青素的产生，并可作为植物转化的可见报告基因。在异源作物如柑橘中评估这些TFs进一步证实，这些基因可用于花青素生产的代谢工程和品种改良。
