Journal Article

PHR1 positively regulates phosphate starvation-induced anthocyanin accumulation through direct upregulation of genes F3’H and LDOX in Arabidopsis

Wang, Yi, Chen, Zhongze, Liu, Zhongjuan, Wang, Enhui, Zheng, Qinghua, Han, Yizhen, Wu, Xueqian, Zhang, Yongqiang, Liu, Yanan

2022

Overview

Main conclusionPhosphate deficiency promotes anthocyanin accumulation inArabidopsisthrough direct binding of PHR1 to the P1BS motifs on the promoters ofF3'HandLDOXand thereby upregulating their expression.Phosphorus is one of the essential elements for plants, and plants mainly absorb inorganic phosphate (Pi) from soil. But Pi deficiency is a common factor limiting plant growth and development. Anthocyanin accumulation in green tissues (such as leaves) is one of the characteristics of many plants in response to Pi starvation. However, little is known about the mechanism by which Pi starvation induces anthocyanin accumulation. Here, we found that the mutation of the gene PHOSPHATE STARVATION RESPONSE1 (PHR1), which encodes a key factor involved in Pi starvation signaling in Arabidopsis, significantly attenuates anthocyanin accumulation under Pi-limiting conditions. Moreover, the expression of several Pi deficiency-upregulated genes that are involved in anthocyanin biosyntheses, such as flavanone 3’-hydroxylase (F3'H), dihydroflavonol 4-reductase (DFR), leucoanthocyanidin dioxygenase (LDOX), and production of anthocyanin pigment 1 (PAP1), was significantly lower in the phr1-1 mutant than in the wild type (WT). Both yeast one-hybrid (Y1H) analysis and chromatin immunoprecipitation quantitative PCR (ChIP-qPCR) showed that PHR1 can interact with the promoters of F3'H and LDOX, but not DFR and PAP1. By electrophoretic mobility shift assay (EMSA), it was further confirmed that the PHR1-binding sequence (P1BS) motifs located on the F3'H and LDOX promoters are required for the PHR1 bindings. Also, in Arabidopsis protoplasts, PHR1 enhanced the transcriptional activity of the F3'H and LDOX promoters, but these effects were markedly impaired when the P1BS motifs were mutated. Taken together, these results indicate that PHR1 positively regulates Pi starvation-induced anthocyanin accumulation in Arabidopsis, at least in part, by directly binding the P1BS motifs located on the promoters to upregulate the transcription of anthocyanin biosynthetic genes F3'H and LDOX.

• Publisher: Springer Nature B.V
• Subject: Accumulation / Anthocyanins / Arabidopsis / Binding / Bioaccumulation / Biosynthesis / Chromatin / Constraining / Dioxygenase / Electrophoretic mobility / Enzymes / Flavonoids / Genes / Hydroxylase / Immunoprecipitation / Laboratories / Leaves / Mutation / Phosphate starvation response / Phosphorus / Physiology / Plant growth / Promoters / Proteins / Protoplasts / Reductases / Yeast