Interactive Effects of Elevated [CO2] and Water Stress on Physiological Traits and Gene Expression during Vegetative Growth in Four Durum Wheat Genotypes

Abstract

The interaction of elevated [CO2] and water stress will have an effect on the adaptation of durum wheat to future climate scenarios. For the Mediterranean basin these scenarios include the rising occurrence of water stress during the first part of the crop cycle. In this study, we evaluated the interactive effects of elevated [CO2] and moderate to severe water stress during the first part of the growth cycle on physiological traits and gene expression in four modern durum wheat genotypes. Physiological data showed that elevated [CO2] promoted plant growth but reduced N content. This was related to a down-regulation of Rubisco and N assimilation genes and up-regulation of genes that take part in C-N remobilization, which might suggest a higher N efficiency. Water restriction limited the stimulation of plant biomass under elevated [CO2], especially at severe water stress, while stomatal conductance and carbon isotope signature revealed a water saving strategy. Transcript profiles under water stress suggested an inhibition of primary C fixation and N assimilation. Nevertheless, the interactive effects of elevated [CO2] and water stress depended on the genotype and the severity of the water stress, especially for the expression of drought stress-responsive genes such as dehydrins, catalase, and superoxide dismutase. The network analysis of physiological traits and transcript levels showed coordinated shifts between both categories of parameters and between C and N metabolism at the transcript level, indicating potential genes and traits that could be used as markers for early vigor in durum wheat under future climate change scenarios. Overall the results showed that greater plant growth was linked to an increase in N content and expression of N metabolism-related genes and down-regulation of genes related to the antioxidant system. The combination of elevated [CO2] and severe water stress was highly dependent on the genotypic variability, suggesting specific genotypic adaptation strategies to environmental conditions.

Interactional Effects of Climate Change Factors on the Water Status, Photosynthetic Rate, and Metabolic Regulation in Peach

“…Previous studies have shown that elevated CO 2 concentrations stimulate photosynthetic carbon gain and net primary production (Leakey et al, 2009;Medina et al, 2016;Afzal et al, 2018). However, in long-term experiments, it has been reported that the initial stimulation of photosynthesis decreases due to acclimation of photosynthetic capacity (Leakey et al, 2009;Aranjuelo et al, 2011;Salazar-Parra et al, 2015;Medina et al, 2016), and that environmental or genetic factors predispose plants to greater or lesser variation (reviewed in Arp, 1991;Leakey et al, 2009 and references therein;Medina et al, 2016). Moreover, elevated CO 2 improves nitrogen-use efficiency and decreases water use in leaves (Medina et al, 2016).…”

“…However, in long-term experiments, it has been reported that the initial stimulation of photosynthesis decreases due to acclimation of photosynthetic capacity (Leakey et al, 2009;Aranjuelo et al, 2011;Salazar-Parra et al, 2015;Medina et al, 2016), and that environmental or genetic factors predispose plants to greater or lesser variation (reviewed in Arp, 1991;Leakey et al, 2009 and references therein;Medina et al, 2016). Moreover, elevated CO 2 improves nitrogen-use efficiency and decreases water use in leaves (Medina et al, 2016). Furthermore, elevated CO 2 stimulates leaf dark respiration via a transcriptional reprogramming of metabolism in soybean, but not in other species (Leakey et al, 2009).…”

“…Plant responses to elevated CO 2 in combination with drought stress and/or temperature increases have been widely studied in different plant species, such as wheat (Erice et al, 2014;Medina et al, 2016), grapevines (Kizildeniz et al, 2015;Salazar-Parra et al, 2015;Martínez-Lüscher et al, 2016;Kizildeniz et al, 2018), alfalfa, soybean, and other plant species (Aranjuelo et al, 2005;Aranjuelo et al, 2006;Baslam et al, 2014;Gray and Brady, 2016 and references therein;Kelly et al, 2016).…”

New insights into the impacts of elevated CO2, nitrogen, and temperature levels on the regulation of C and N metabolism in durum wheat using network analysis

“…physiological parameters and gene expression [8], enzyme activities and metabolite levels [9], or quantitative trait loci (QTLs) and sensory and metabolic traits [10]. Such research is currently best done in model plants, like Arabidopsis, rice or poplar [1,7,11], but much less effort has been dedicated to crop species as maize [12,13], barley [14], bread wheat [6] and durum wheat [15]. This cereal is one of the most widespread crops in the Mediterranean basin used mainly for the production of pasta and accounting for approximately 8% of the global wheat production [16].…”

Modulation of photosynthate supply by CO2 elevation affects the post‐head‐emergence frost‐induced grain yield loss in wheat

“…It has been well documented that an increase in photosynthate supply, for example, by increasing atmospheric CO 2 concentration (hereafter abbreviated as [CO 2 ]), has both direct and indirect effects on plant growth and stress responses in wheat (Li, Hou, & Trent, 2001;Medina, Vicente, Amador, & Araus, 2016;Pinter et al, 2001;Varga, Vida, Varga-László, Hoffmann, & Veisz, 2017). For instance, it has a direct and positive effect on wheat plant growth (Stitt & Krapp, 1999;Wang, Feng, & Schjoerring, 2013) and grain yield (Wang et al, 2013).…”