PfWRI1-10 transcription factor mediates lipid synthesis in Perilla frutescens through regulating PfBCCP1 gene transcription

BACKGROUND: Perilla frutescens is an oilseed crop rich in unsaturated fatty acids (UFAs). WRINKLED1 (WRI1) is an AP2/EREBP-type transcription factor (TF), which plays important regulation roles in fatty acid (FA) metabolism. RESULTS: In this study, 11 PfWRI1 members were identified in the perilla genome. qRT-PCR analysis revealed that PfWRI1-10 was expressed higher than other members in developing seeds of perilla, suggesting that PfWRI1-10 may play crucial roles in seed oil biosynthesis. Overexpression of PfWRI1-10 resulted in enhancement of total oil content by 9.75% and α-linolenic acid (C18:3) level by 0.43%, while the soluble sugar content decreased in the transgenic tobacco leaves. qRT-PCR showed that the expression levels of glycolysis gene (NtPKp-β1) and FA biosynthesis genes (NtACP1 and NtBCCP1) significantly upregulated, whereas NtKAS1-B expression was downregulated in transgenic tobacco plants, indicating that PfWRI1-10 reallocated carbon sources flow to facilitate lipid biosynthesis by regulating the expression of the target genes. Yeast one-hybrid (Y1H) assays demonstrate that PfWRI1-10 directly binds to the AW-box cis-element of the PfBCCP1 promoter. Overexpression of PfBCCP1 enhanced the lipid content in the transgenic yeast, confirming its function in lipid metabolism. CONCLUSIONS: PfWRI1-10 transcription factor promotes lipid biosynthesis by upregulating PfBCCP1 and other lipid related genes. The current findings provide a scientific basis for the in-depth analysis of the regulatory network of perilla oil biosynthesis and also valuable genes for genetic improvement of perilla oil yield and quality.