title: Physiological, biochemical, and genome-wide transcriptional analysis reveals that elevated CO2 mitigates the impact of combined heat wave and drought stress in Arabidopsis thaliana at multiple organizational levels.
abstract: Climate changes increasingly threaten plant growth and productivity. Such changes are complex and involve multiple environmental factors, including rising CO2 levels and climate extreme events. As the molecular and physiological mechanisms underlying plant responses to realistic future climate extreme conditions are still poorly understood, a multiple organizational level analysis (i.e. eco-physiological, biochemical, and transcriptional) was performed, using Arabidopsis exposed to incremental heat wave and water deficit under ambient and elevated CO2 . The climate extreme resulted in biomass reduction, photosynthesis inhibition, and considerable increases in stress parameters. Photosynthesis was a major target as demonstrated at the physiological and transcriptional levels. In contrast, the climate extreme treatment induced a protective effect on oxidative membrane damage, most likely as a result of strongly increased lipophilic antioxidants and membrane-protecting enzymes. Elevated CO2 significantly mitigated the negative impact of a combined heat and drought, as apparent in biomass reduction, photosynthesis inhibition, chlorophyll fluorescence decline, H2 O2 production, and protein oxidation. Analysis of enzymatic and molecular antioxidants revealed that the stress-mitigating CO2 effect operates through up-regulation of antioxidant defense metabolism, as well as by reduced photorespiration resulting in lowered oxidative pressure. Therefore, exposure to future climate extreme episodes will negatively impact plant growth and production, but elevated CO2 is likely to mitigate this effect.
authors.affiliation: Research Group of Plant and Vegetation Ecology, Department of Biology, University of Antwerp, Universiteitsplein 1, Antwerp, Wilrijk, B-2610, Belgium; Laboratory for Molecular Plant Physiology and Biotechnology, Department of Biology, University of Antwerp, Groenenborgerlaan 171, Antwerp, B-2020, Belgium.
authors.forename: Gaurav
authors.initials: G
authors.lastname: Zinta
authors.forename: Hamada
authors.initials: H
authors.lastname: AbdElgawad
authors.forename: Malgorzata A
authors.initials: MA
authors.lastname: Domagalska
authors.forename: Lucia
authors.initials: L
authors.lastname: Vergauwen
authors.forename: Dries
authors.initials: D
authors.lastname: Knapen
authors.forename: Ivan
authors.initials: I
authors.lastname: Nijs
authors.forename: Ivan A
authors.initials: IA
authors.lastname: Janssens
authors.forename: Gerrit T S
authors.initials: GT
authors.lastname: Beemster
authors.forename: Han
authors.initials: H
authors.lastname: Asard
mesh_terms: D000704:Analysis of Variance; D061745:Antioxidant Response Elements / Q000502:physiology; D017360:Arabidopsis / Q000235:genetics / Q000502:physiology*; D018533:Biomass; D002245:Carbon Dioxide / Q000378:metabolism*; D057231:Climate Change; D003198:Computer Simulation; D055864:Droughts; D020869:Gene Expression Profiling; D006358:Hot Temperature / Q000009:adverse effects*; D006861:Hydrogen Peroxide / Q000378:metabolism; D046228:Microarray Analysis; D008954:Models, Biological; D010788:Photosynthesis / Q000502:physiology; D013312:Stress, Physiological / Q000502:physiology*
chemical_list: D002245:Carbon Dioxide; D006861:Hydrogen Peroxide
keywords: antioxidants; biomass; climate change; gene expression; oxidative stress; photorespiration; photosynthesis