Got vitamin C? A metabolic GWAS analysis identified a PAS/LOV PROTEIN regulating ascorbate accumulation

• DOI: 10.1093/plphys/kiad462
• Publication Date: 2023-08-25T00:19:54Z
• Authors: Maria-Angelica Sa...
• Keywords: Genome-wide Association Study

Ascorbate or vitamin C is an essential component of many cellular processes including hormone metabolism, chloroplast electron transport, and redox balance (Noctor Foyer 1998; Ivanov Khorobrykh 2003; 2014; et al., 2020).It well established that ascorbate accumulates in response to high light (> 300 µmol m -2 s -1 ) where it acts as a reactive oxygen species (ROS) scavenger, contributing stress tolerance plants (Hasanuzzaman 2019; Xiao 2021).Despite these vital roles, aspects biosynthesis regulation remain poorly understood.In plants, synthesized from phosphorylated hexose sugars such glucose, fructose, mannose (Figure 1A).A key step produce L-galactose-1-phosphate, reaction catalyzed by the GDP-L-galactose phosphorylase (GGP).In Arabidopsis, GGP encoded two paralogous genes VTC2 VTC5 (Fenech 2021).High induces transcription activates activity, which turn regulates production different ways.For instance, upstream open reading frame 5'-untranslated region represses translation feedback mechanism (Laing 2015).Moreover, positive negative interaction partners can impact light-dark pools.One regulators PAS/LOV protein (PLP) contains N-terminal Per-ARNT (PAS) domain C-terminal light-oxygen-voltage (LOV) domain, suggesting regulatory role for PLP blue-light reception (Ogura al, 2008b; Kasahara 2010).Previously, Ogura 2008b showed proteins PLPA PLPB bind VTC2.Light conditions affect interactions between VTC2.Blue weakens while darkness enhances it, leading changes levels each condition.In this issue Plant Physiology, Arabi 2023 used metabolic GWAS approach gain insight into during light.Their initial analysis found significant association SNPs gene coding with enhanced pools light.This was not observed control conditions.Subsequent analyses demonstrated both colocalize nucleus cytoplasm.The strength their affected blue light, consistent previous findings 1B Figure 1C).Characterization knock-down mutants increased accumulation expression regardless conditions, may play via extends beyond irradiation.The work interesting reveals new features through acclimation.Moreover, generates relevant questions hypotheses provide framework future studies.For authors