School of Biological Sciences, Nanyang Technological University, Singapore 637551, Singapore.
MSU-DOE Plant Research Laboratory, Michigan State University, East Lansing, Michigan 48824.
Plant Physiol. 2020 Oct;184(2):658-665. doi: 10.1104/pp.20.00547. Epub 2020 Jul 6.
Cross-family transcription factor (TF) interactions play critical roles in the regulation of plant developmental and metabolic pathways. WRINKLED1 (WRI1) is a key TF governing oil biosynthesis in plants. However, little is known about WRI1-interacting factors and their roles in oil biosynthesis. We screened a TF library using Arabidopsis () WRI1 (AtWRI1) as bait in yeast two-hybrid assays and identified three TEOSINTE BRANCHED1/CYCLOIDEA/PROLIFERATING CELL FACTOR (TCP) family TFs, namely TCP4, TCP10, and TCP24, as AtWRI1-interacting partners. The physical interaction between AtWRI1 and TCPs was further validated using bimolecular fluorescence complementation assays. TCPs play important roles in various plant developmental processes; however, their involvement in fatty acid biosynthesis was not previously known. Coexpression of TCP4, but not TCP10 or TCP24, with AtWRI1 reduced AtWRI1-mediated oil biosynthesis in leaves. Transcriptomic analysis in transgenic Arabidopsis plants with enhanced TCP4 activity engineered by expressing (i.e. miR319-resistant ) revealed that AtWRI1 target genes were significantly repressed. TCP4 expression is strongly correlated with AtWRI1 during embryo development. A loss-of-function mutant, the mutant with a strong reduction of expression, and a triple mutant accumulated more seed oil than wild-type Arabidopsis. In addition, TCP4 repressed the AtWRI1-mediated transactivation of the promoters of fatty acid biosynthetic genes. Collectively, our findings suggest that TCP4 represses fatty acid biosynthetic gene expression through interaction with AtWRI1, leading to a reduction of AtWRI1-mediated seed oil accumulation.
跨家族转录因子（TF）相互作用在植物发育和代谢途径的调控中起着关键作用。WRINKLED1（WRI1）是一种关键的 TF，负责植物油脂的生物合成。然而，关于 WRI1 相互作用因子及其在油脂生物合成中的作用知之甚少。我们使用拟南芥（Arabidopsis）WRI1（AtWRI1）作为酵母双杂交分析中的诱饵筛选 TF 文库，鉴定出三个 TEOSINTE BRANCHED1/CYCLOIDEA/PROLIFERATING CELL FACTOR（TCP）家族 TF，即 TCP4、TCP10 和 TCP24，为 AtWRI1 的互作伙伴。使用双分子荧光互补测定进一步验证了 AtWRI1 与 TCPs 之间的物理相互作用。TCPs 在各种植物发育过程中发挥重要作用；然而，它们在脂肪酸生物合成中的参与先前未知。TCP4 与 AtWRI1 的共表达，而不是 TCP10 或 TCP24，降低了 叶片中 AtWRI1 介导的油脂生物合成。通过表达 （即 miR319 抗性）增强 TCP4 活性的转基因拟南芥植物的转录组分析表明，AtWRI1 靶基因显著受到抑制。TCP4 的表达在胚胎发育过程中与 AtWRI1 强烈相关。一个功能丧失突变体，即表达 （即 miR319 抗性）强烈减少的 突变体，和一个 三重突变体比野生型拟南芥积累更多的种子油。此外，TCP4 抑制了 AtWRI1 介导的脂肪酸生物合成基因启动子的转录激活。总之，我们的研究结果表明，TCP4 通过与 AtWRI1 相互作用抑制脂肪酸生物合成基因的表达，导致 AtWRI1 介导的种子油积累减少。
