Arabidopsis NAC Transcription Factor, ANAC078, Regulates Flavonoid Biosynthesis under High-light

Abstract

We have isolated a combination of high-light and heat-shock (HL + HS) stress-inducible genes, including a NAC transcription factor designated ANAC078. Here we explored the physiological function of ANAC078 under HL stress. Yeast transcription activity assays showed that ANAC078 functions as a transcriptional activator. A fusion protein composed of green fluorescent protein (GFP) and full-length ANAC078 was detected in the nucleus and cytoplasm, while fusion proteins comprising GFP and ANAC078 deleted of a putative transmembrane motif were found only in the nucleus. In ANAC078-overexpressing Arabidopsis plants (Ox-ANAC078-43), the transcription of 166 genes was up-regulated compared with the levels in wild-type plants under HL (1200 micromol m(-2) s(-1), 30 degrees C). These genes included some for transcription factors regulating the expression of genes related to the biosynthesis of flavonoids. Interestingly, the transcript levels of some genes related to flavonoid biosynthesis and the levels of anthocyanins were significantly increased in Ox-ANAC078 plants and reduced in knockout ANAC078 plants (KO-ANAC078) compared with wild-type plants under HL stress. The present findings suggest that ANAC078 protein is associated with the induction of genes related to flavonoid biosynthesis, leading to the accumulation of anthocyanins, in response to HL stress.

The Membrane-Bound NAC Transcription Factor ANAC013 Functions in Mitochondrial Retrograde Regulation of the Oxidative Stress Response in Arabidopsis

“…Previous functional studies indicated that ANAC078 regulates light stress-dependent flavonoid biosynthesis and proteasome levels (Morishita et al, 2009;Yabuta et al, 2011). In transgenic Arabidopsis plants overexpressing ANAC053, leaf senescence was promoted during drought stress (Lee et al, 2012).…”

Regulation of stilbene biosynthesis in plants

“…The transcription factors and transcription complexes can act as positive or negative regulators in flavonoid biosynthesis Yang et al 2017). Other transcription factors, apart from R2R3-MYBs and bHLHs, e.g., Basic Leucine Zipper Domain (bZIP) or NAC, have been reported as positive regulators of flavonoid biosynthesis (Morishita et al 2009;Malacarne et al 2016). The single repeat MYBs (R3-MYBs), squamosa promoter binding protein like (SPL), or some NAC TFs, have been reported as negative regulators of flavonoid biosynthesis in plants (Dubos et al 2008;Gou et al 2011;Dalman et al 2017).…”

Role of Plant Transcription Factors in Abiotic Stress Tolerance

“…GmNAC1, GmNAC5 and GmNAC6 transiently expressed in tobacco leaves, resulting in cell death and enhanced expression of senescence markers. Flavonoid biosynthesis is regulated by ANAC078 under high-light (Morishita et al, 2009). A rice NAC gene, ONAC045 was induced by drought, high salt, low temperature, and ABA treatment in leaves and roots (Zheng et al, 2009).…”