Day length is a key regulator of transcriptomic responses to both CO₂ and H₂O₂ in Arabidopsis

Abstract

Growth day length, CO2 levels and H2O2 all impact plant function, but interactions between them remain unclear. Using a whole-genome transcriptomics approach, we identified gene expression patterns responding to these three factors in Arabidopsis Col-0 and the conditional catalasedeficient mutant, cat2. Plants grown for 5 weeks at high CO2 in short days (hCO2) were transferred to air in short days (SD air) or long days (LD air), and microarray data produced were subjected to three independent studies. The first two analysed genotype-independent responses. They identified 1549 genes differentially expressed after transfer from hCO2 to SD air. Almost half of these, including genes modulated by sugars or associated with redox, stress or abscisic acid (ABA) functions, as well as light signalling and clock genes, were no longer significant after transfer to air in LD. In a third study, day length-dependent H2O2-responsive genes were identified by comparing the two genotypes. Two clearly independent responses were observed in cat2 transferred to air in SD and LD. Most H2O2-responsive genes were up-regulated more strongly in SD air. Overall, the analysis shows that both CO2 and H2O2 interact with day length and photoreceptor pathways, indicating close networking between carbon status, light and redox state in environmental responses.

Photorespiration Is Crucial for Dynamic Response of Photosynthetic Metabolism and Stomatal Movement to Altered CO 2 Availability

“…The transpiration rate returned to normal within 5 days ( Figure 4A), as did the transcriptional response after a shift from HC to LC conditions (Queval et al, 2012). In mutant plants, glyk1 and pglp1 showed likewise significant ABA accumulation, and hpr1 and shm1 displayed a nonsignificant trend toward ABA accumulation ( Figure 4B).…”

A Key Role for Apoplastic H2O2 in Norway Spruce Phenolic Metabolism

“…9B) and UDP-Glc/GlcA transferases in lignin-forming conditions suggests that the synthesis of glutathione and sugar conjugates was increased during lignin formation, further supporting that cells under lignin-forming conditions were subjected to oxidative stress. The up-regulation of similar transferase genes together with those of cytochrome P450s has been shown to be typical for a catalasedeficient Arabidopsis mutant that suffers from oxidative stress (Queval et al, 2012;Noctor et al, 2015). Glutathione S-transferases, for example, catalyze the conjugation of oxidized lipid compounds to glutathione (Farmer and Mueller, 2013;Noctor et al, 2015).…”

Serine Acts as a Metabolic Signal for the Transcriptional Control of Photorespiration-Related Genes in Arabidopsis

“…It is not exactly known, however, how this light-dependent control is coordinated with the control exerted by other environmental and internal factors. For example, a broad range of transcription factors responds to changes in the CO 2 concentration, whereas photorespiration-related transcripts remain largely unaffected (Foyer et al, 2012;Queval et al, 2012). It is also not known whether a specific regulation of photorespiratory metabolism, including the transcription of relevant genes, occurs.…”

“…For the HPR1 gene, transcriptional repression in high CO 2 has been observed (Bertoni and Becker, 1996). This effect of changes in the CO 2 concentration on HPR1 expression probably cannot be generalized, because the expression of genes encoding other photorespiratory enzymes is not significantly altered (Foyer et al, 2012;Queval et al, 2012).…”