Environmental regulation of leaf colour in red 35S:PAP1 Arabidopsis thaliana

Abstract

Summary• High-temperature, low-light (HTLL) treatment of 35S:PAP1 Arabidopsis thaliana over-expressing the PAP1 (Production of Anthocyanin Pigment 1) gene results in reversible reduction of red colouration, suggesting the action of additional anthocyanin regulators. High-performance liquid chromatography (HPLC), liquid chromatography mass spectrometry (LCMS) and Affimetrix ® -based microarrays were used to measure changes in anthocyanin, flavonoids, and gene expression in response to HTLL.• HTLL treatment of control and 35S:PAP1 A. thaliana resulted in a reversible reduction in the concentrations of major anthocyanins despite ongoing over-expression of the PAP1 MYB transcription factor. Twenty-one anthocyanins including eight ciscoumaryl esters were identified by LCMS. The concentrations of nine anthocyanins were reduced and those of three were increased, consistent with a sequential process of anthocyanin degradation. Analysis of gene expression showed down-regulation of flavonol and anthocyanin biosynthesis and of transport-related genes within 24 h of HTLL treatment. No catabolic genes up-regulated by HTLL were found.• Reductions in the concentrations of anthocyanins and down-regulation of the genes of anthocyanin biosynthesis were achieved by environmental manipulation, despite ongoing over-expression of PAP1. Quantitative PCR showed reduced expression of three genes (TT8, TTG1 and EGL3) of the PAP1 transcriptional complex, and increased expression of the potential transcriptional repressors AtMYB3, AtMYB6 and AtMYBL2 coincided with HTLL-induced down-regulation of anthocyanin biosynthesis.• HTLL treatment offers a model system with which to explore anthocyanin catabolism and to discover novel genes involved in the environmental control of anthocyanins.

The Jasmonate-ZIM-Domain Proteins Interact with the WD-Repeat/bHLH/MYB Complexes to Regulate Jasmonate-Mediated Anthocyanin Accumulation and Trichome Initiation inArabidopsis thaliana

“…Upon JA treatment or JA biosynthesis stimulated by diverse developmental and environmental signals, the JA signal induces degradation of JAZ proteins through the SCF COI1 -26S proteasome pathway (Chini et al, 2007;Thines et al, 2007;; the WD-repeat/bHLH/MYB complexes are then released to activate their respective downstream transcriptional cascades, leading to anthocyanin biosynthesis and trichome formation. Many other signals, including environmental signals (cold, high light, and insect attack) and endogenous signals (cytokinins and gibberellin), were shown to regulate anthocyanin accumulation or trichome formation (Deikman and Hammer, 1995;Gan et al, 2007;Cominelli et al, 2008;Loreti et al, 2008;Rowan et al, 2009;Yoshida et al, 2009;Yu et al, 2010). These signals may influence anthocyanin accumulation and trichome initiation also through directly or indirectly regulating WD-repeat/bHLH/MYB complexes by virtue of bHLH and R2R3 MYB components as well as the WD-repeat protein TTG1.…”

“…In Arabidopsis thaliana, the WD-repeat protein Transparent Testa Glabra1 (TTG1) (Walker et al, 1999) recruits basic-helixloop-helix (bHLH) transcription factors (Toledo-Ortiz et al, 2003), such as Glabra3 (GL3) (Payne et al, 2000), Transparent Testa8 (TT8) (Nesi et al, 2000;Baudry et al, 2006), or Enhancer of Glabra3 (EGL3) , and R2R3 MYB transcriptional factors (MYB75, MYB90, MYB113, or MYB114) (Borevitz et al, 2000;Stracke et al, 2001;Zimmermann et al, 2004;Stracke et al, 2007;Allan et al, 2008;Gonzalez et al, 2008;Rowan et al, 2009) to form the WD-repeat/bHLH/MYB complex, which mediates anthocyanin biosynthesis mainly by upregulating the expression of late anthocyanin biosynthetic genes, including NADPH-dependent dihydroflavonol reductase (DFR), leucoanthocyanidin dioxygenase (LDOX), and UDP-Glc:flavonoid 3-Oglucosyltransferase (UF3GT) (Dooner et al, 1991;Kubasek et al, 1992;Shirley et al, 1995;Gonzalez et al, 2008).…”

MdCOP1 Ubiquitin E3 Ligases Interact with MdMYB1 to Regulate Light-Induced Anthocyanin Biosynthesis and Red Fruit Coloration in Apple

“…In Arabidopsis, petunia, maize, A. majus, and fruit trees, it has been shown that MYB TFs, together with basic helix-loop-helix TFs and WD-40 repeat proteins, regulate anthocyanin biosynthesis and therefore contribute to the red coloration of various organs including the leaves, flowers, and fruits (Mol et al, 1998;Allan et al, 2008). Generally, light induces the expression of anthocyanin-associated MYB genes, and therefore favors red pigment accumulation in plant organs (Mol et al, 1998;Allan et al, 2008;Gonzalez, 2009;Rowan et al, 2009). In apple, the fruit peel does not develop a red color without light, but it rapidly initiates coloration upon exposure to sunlight in a process that is regulated by MdMYB1 and its alleles (Takos et al, 2006;Ban et al, 2007;Allan et al, 2008).…”

MYB75 Phosphorylation by MPK4 Is Required for Light-Induced Anthocyanin Accumulation in Arabidopsis

“…In Arabidopsis, anthocyanin accumulation only occurs in the light (Maier et al, 2013) and the levels of anthocyanin accumulation are light intensity dependent (Rowan et al, 2009;Shi and Xie, 2010). In this study, we maintained Arabidopsis seedlings under weak light of 40 mmol m 22 s 21 (hereafter called low light), a control light intensity at which wild-type plants accumulate very low levels of anthocyanins (Shi and Xie, 2010;Maier and Hoecker, 2015) (Figures 2A and 2B).…”