Ultraviolet‐B‐induced stress and changes in gene expression in Arabidopsis thaliana: role of signalling pathways controlled by jasmonic acid, ethylene and reactive oxygen species

Abstract

Treatment with supplementary UV‐B resulted in decreases in transcripts of the photosynthetic genes Lhcb and psbA and concomitant increase in transcripts of two pathogen‐related genes, PR‐1 and PDF1·2, in Arabidopsis thaliana. UV‐B exposure caused increases in jasmonic acid (JA) levels and ethylene production. UV‐B treatment of jar1 and etr1‐1 mutants, which are insensitive to JA and ethylene, respectively, showed that the increase in PR‐1 transcripts was dependent on ethylene and PDF1·2 transcripts on both JA and ethylene. In contrast, the down‐regulation of photosynthetic transcripts was independent of both compounds. Previous studies have indicated a role for reactive oxygen species (ROS) in the UV‐B‐induced down‐regulation of the photosynthetic genes and up‐regulation of PR‐1 genes. Here we have shown that ROS are also required for the UV‐B‐induced up‐regulation of PDF1·2 genes. The results indicate that the effects of UV‐B on the three sets of genes are mediated through three distinct signal transduction pathways which are similar, but not identical, to pathways initiated in response to pathogen infection. In addition, the increased sensitivity of both jar1 and etr1‐1 mutants to UV‐B radiation, as compared with wild‐type plants, indicated that intact JA and ethylene signal pathways are required for defence against UV‐B damage.

An endogenous peptide signal in Arabidopsis activates components of the innate immune response

“…The induction of both H 2 O 2 and PDF1.2 by AtPep1 was blocked by first supplying the leaves with diphenylene iodominium chloride (DPI) (Fig. 3 C and D), an inhibitor of NADPH oxidase in both plant and animal tissues (20,29). The cumulative results indicated that AtPep1 requires H 2 O 2 for the transcription of PDF1.2, consistent with recently proposed pathways for JA͞ethylene signaling (28).…”

An RNA-Seq Transcriptome Analysis of Orthophosphate-Deficient White Lupin Reveals Novel Insights into Phosphorus Acclimation in Plants

“…Those authors (Shin et al, 2005;Torabi et al, 2009) found the severity of P i deficiency directly correlated with the severity of the oxidative stress. Increased oxidative stress and ROS accumulation are known photosynthesis inhibitors (Mackerness et al, 1999). The majority of transcripts down-regulated in leaves due to P i deficiency ( Fig.…”

Ultraviolet-B Activates Components of the Systemin Signaling Pathway in Lycopersicon peruvianum Suspension-cultured Cells

“…This article must therefore be hereby marked "advertisement" in accordance with 18 U.S.C. systemin show striking similarities to UV-B signaling, including proton and potassium fluxes (25)(26)(27), increases in intracellular Ca 2ϩ concentrations (28 -30), activation of calmodulin genes (28,31,32), activation of MAPKs (15,22,33,34), activation of an NADPH-dependent oxidase (35)(36)(37), generation of reactive oxygen species (11,25,35,38), and increases in levels of ethylene (27,39,40), and jasmonic acid (39,41,42). However, it is still largely unknown how these signaling events are initiated by UV-B, what their precise cellular function is, and whether wounding/systemin-induced pathways and UV-B-induced pathways utilize some common signaling components.…”