Sánchez Rosario, González-Thuillier Irene, Venegas-Calerón Mónica, Garcés Rafael, Salas Joaquín J, Martínez-Force Enrique
Instituto de la Grasa (CSIC), Pablo de Olavide University Campus, Building 46, Carretera de Utrera km 1, 41013 Seville, Spain.
Jealotts Hill International Research Centre, Bracknell, Berkshire RG42 6EY, UK.
Plants (Basel). 2022 Apr 2;11(7):972. doi: 10.3390/plants11070972.
Sunflower is an important oilseed crop in which the biochemical pathways leading to seed oil synthesis and accumulation have been widely studied. However, how these pathways are regulated is less well understood. The WRINKLED1 (WRI1) transcription factor is considered a key regulator in the control of triacylglycerol biosynthesis, acting through the AW box binding element (CNTNG(N)CG). Here, we identified the sunflower gene and characterized its activity in electrophoretic mobility shift assays. We studied its role as a co-regulator of sunflower genes involved in plastidial fatty acid synthesis. Sunflower WRI1-targets included genes encoding the pyruvate dehydrogenase complex, the α-CT and BCCP genes, genes encoding ACPs and the fatty acid synthase complex, together with the gene. As such, sunflower WRI1 regulates genes involved in seed plastidial fatty acid biosynthesis in a coordinated manner, establishing a WRI1 push and pull strategy that drives oleic acid synthesis for its export into the cytosol. We also determined the base bias at the N positions in the active sunflower AW box motif. The sunflower AW box is sequence-sensitive at the non-conserved positions, enabling WRI1-binding. Moreover, sunflower WRI1 could bind to a non-canonical AW-box motif, opening the possibility of searching for new target genes.
向日葵是一种重要的油料作物，其种子油合成和积累的生化途径已得到广泛研究。然而，这些途径如何被调控却知之甚少。皱叶1（WRI1）转录因子被认为是三酰甘油生物合成控制中的关键调节因子，通过AW盒结合元件（CNTNG(N)CG）发挥作用。在这里，我们鉴定了向日葵基因，并在电泳迁移率变动分析中表征了其活性。我们研究了它作为参与质体脂肪酸合成的向日葵基因的共调节因子的作用。向日葵WRI1的靶标包括编码丙酮酸脱氢酶复合体的基因、α-CT和BCCP基因、编码ACP的基因以及脂肪酸合酶复合体，还有基因。因此，向日葵WRI1以协调的方式调节参与种子质体脂肪酸生物合成的基因，建立了一种WRI1推拉策略，驱动油酸合成并将其输出到细胞质中。我们还确定了活性向日葵AW盒基序中N位置的碱基偏好。向日葵AW盒在非保守位置对序列敏感，能够实现WRI1结合。此外，向日葵WRI1可以结合非典型的AW盒基序，为寻找新的靶基因开辟了可能性。
