TEOSINTE BRANCHED1/CYCLOIDEA/PROLIFERATING CELL FACTOR4 Interacts with WRINKLED1 to Mediate Seed Oil Biosynthesis

• Published in: Plant physiology (Bethesda) Vol. 184; no. 2; pp. 658 - 665
• Main Authors: Kong, Que, Singh, Sanjay K, Mantyla, Jenny J, Pattanaik, Sitakanta, Guo, Liang, Yuan, Ling, Benning, Christoph, Ma, Wei
• Format: Journal Article
• Language: English
• Published: United States American Society of Plant Biologists 01.10.2020
• Subjects: Arabidopsis; Arabidopsis Proteins - metabolism; Fatty Acids - biosynthesis; Nicotiana; Plant Sciences; Seeds - growth & development; Seeds - metabolism; Transcription Factors - metabolism
• ISSN: 0032-0889; 1532-2548
• DOI: 10.1104/pp.20.00547

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.