Metabolomic and physiological responses reveal multi‐phasic acclimation of Arabidopsis thaliana to chronic UV radiation

Abstract

Biochemical changes in vivo and pathway interactions were investigated using integrated physiological and metabolic responses of Arabidopsis thaliana L. to ultraviolet (UV) radiation (280-400 nm) at 9.96 kJ m -2 d -1 over the entire life cycle from seed to seed (8 weeks). Columbia-0 (Col-0) and a UV-B sensitive accession ( fah-1) showed significant (P < 0.001) reductions in leaf growth after 6 weeks. Col-0 recovered growth after 8 weeks, with recovery corresponding to a switch from production of phenylpropanoids to flavonoids. fah-1 failed to recover, indicating that sinapate production is an essential component of recovery. Epidermal features show that UV radiation caused significant (P < 0.001) increases in trichome density, which may act as a structural defence response. Stomatal indices showed a significant (P < 0.0001) reduction in Col-0 and a significant (P < 0.001) increase in fah-1. Epidermal cell density was significantly increased under UV radiation on the abaxial leaf surface, suggesting that that a fully functioning phenylpropanoid pathway is a requirement for cell expansion and leaf development. Despite wild-type acclimation, the costs of adaptation lead to reduced plant fitness by decreasing flower numbers and total seed biomass. A multi-phasic acclimation to UV radiation and the induction of specific metabolites link stress-induced biochemical responses to enhanced acclimation.

Enhanced UV-B and Elevated CO2 Impacts Sub-Arctic Shrub Berry Abundance, Quality and Seed Germination

“…These findings differ from those of laboratory based studies on seeds where UV-B reduced seed size and numbers (e.g. Lake et al 2009;Singh et al 2010).…”

“…UV-B alone has been studied in the context of seed production and viability (van de Staaij et al 1997;Wang et al 2008;Lake et al 2009) and also as a potential tool to manipulate or beneficially enhance the secondary metabolite chemistry of fruit and vegetables (see review by Jansen et al 2008). For example, research has been conducted on UV-B impacts on grape berries due to commercial interest in fruit characteristics and resultant wine quality.…”

Occupation of bare habitats, an evolutionary precursor to soil specialization in plants

“…Abiotically, life in bare microhabitats might require adaptations to increased disturbance (45), rockiness, drought (55), and exposure to high levels of UV light (36). Adaptations like the production of heat-shock proteins and UV-absorbing phenols and flavonoids may have costs that reduce competitive ability (56,57). Likewise, adaptations to disturbance, which are associated with a lack of vegetation cover in serpentine and other bare soils (45,52) and which may perpetuate a lack of vegetation (58), may also have costs.…”

Antioxidant capacity, total phenolic and ascorbate content as a function of the genetic diversity of leek (Allium ampeloprasum var. porrum)

“…Notably, all studies dealing with high UV stress found an increase in antioxidants, and especially phenolics concentration in various crops (Wang & Frei, 2011). Flavonoids, one of the largest classes of plant phenolic, protect plant cells from UV-B radiation because they accumulate in epidermal layers of leaves and stems and absorb light strongly in the UV-B region while letting visible (PAR) wavelengths throughout uninterrupted (Lake, Field, Davey, Beerling, & Lomax, 2009). In addition, exposure of plants to increased UV-B light has demonstrated to increase the synthesis of flavones and flavonols.…”