Cytosolic Dehydroascorbate Reductase is Important for Ozone Tolerance in Arabidopsisthaliana

Yoshida, Seiji; Tamaoki, Masanori; Shikano, Takeshi; Nakajima, Nobuyoshi; Ogawa, Daisuke; Ioki, Motohide; Aono, Mitsuko; Kubo, Akihiro; Kamada, Hiroshi; Inoue, Yasunori; Saji, Hikaru

doi:10.1093/pcp/pci246

Cited by 115 publications

(101 citation statements)

References 21 publications

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“…A minor contribution to the cytosolic activity would come from DHAR2. This is consistent with two recent reports on single dhar mutants (Noshi et al, 2016(Noshi et al, , 2017 but in contrast to an earlier analysis of dhar2 (Yoshida et al, 2006).…”

Section: Discussionsupporting

confidence: 93%

“…To date, three studies have appeared using single loss-offunction mutants. The earliest reported a substantial effect on the extractable activity (about 30% of the wildtype value) and effects on ozone resistance in dhar2 (Yoshida et al, 2006). Very recently, a much smaller decrease was reported in a line lacking DHAR2 function, with most of the activity associated with DHAR1.…”

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confidence: 99%

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Cytosolic and Chloroplastic DHARs Cooperate in Oxidative Stress-Driven Activation of the Salicylic Acid Pathway

Rahantaniaina

Li²,

Châtel-Innocenti³

et al. 2017

Plant Physiol.

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The complexity of plant antioxidative systems gives rise to many unresolved questions. One relates to the functional importance of dehydroascorbate reductases (DHARs) in interactions between ascorbate and glutathione. To investigate this issue, we produced a complete set of loss-of-function mutants for the three annotated Arabidopsis (Arabidopsis thaliana) DHARs. The combined loss of DHAR1 and DHAR3 expression decreased extractable activity to very low levels but had little effect on phenotype or ascorbate and glutathione pools in standard conditions. An analysis of the subcellular localization of the DHARs in Arabidopsis lines stably transformed with GFP fusion proteins revealed that DHAR1 and DHAR2 are cytosolic while DHAR3 is chloroplastic, with no evidence for peroxisomal or mitochondrial localizations. When the mutations were introduced into an oxidative stress genetic background (cat2), the dhar1 dhar2 combination decreased glutathione oxidation and inhibited cat2-triggered induction of the salicylic acid pathway. These effects were reversed in cat2 dhar1 dhar2 dhar3 complemented with any of the three DHARs. The data suggest that (1) DHAR can be decreased to negligible levels without marked effects on ascorbate pools, (2) the cytosolic isoforms are particularly important in coupling intracellular hydrogen peroxide metabolism to glutathione oxidation, and (3) DHAR-dependent glutathione oxidation influences redox-driven salicylic acid accumulation.

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Section: Discussionsupporting

confidence: 93%

mentioning

confidence: 99%

Cytosolic and Chloroplastic DHARs Cooperate in Oxidative Stress-Driven Activation of the Salicylic Acid Pathway

Rahantaniaina

Li²,

Châtel-Innocenti³

et al. 2017

Plant Physiol.

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“…Such a localisation has been confi rmed by identifying DHAR3 in the chloroplast proteome (Zybailov et al, 2008), though in vitro transport assays failed to show such import into either chloroplasts or mitochondria (Chew et al, 2003). Perhaps surprisingly for genes encoding proteins which counteract oxidising conditions, within the class only DHAR2 transcripts have been shown to accumulate in response to stress (Dixon et al, 2002b;Yoshida et al, 2006).…”

Section: Microarray Studiesmentioning

confidence: 99%

Glutathione Transferases

Dixon

Edwards

2010

The Arabidopsis Book

198

222

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The 55 Arabidopsis glutathione transferases (GSTs) are, with one microsomal exception, a monophyletic group of soluble enzymes that can be divided into phi, tau, theta, zeta, lambda, dehydroascorbate reductase (DHAR) and TCHQD classes. The populous phi and tau classes are often highly stress inducible and regularly crop up in proteomic and transcriptomic studies. Despite much study on their xenobiotic-detoxifying activities their natural roles are unclear, although roles in defence-related secondary metabolism are likely. The smaller DHAR and lambda classes are likely glutathione-dependent reductases, the zeta class functions in tyrosine catabolism and the theta class has a putative role in detoxifying oxidised lipids. This review describes the evidence for the functional roles of GSTs and the potential for these enzymes to perform diverse functions that in many cases are not "glutathione transferase" activities. As well as biochemical data, expression data from proteomic and transcriptomic studies are included, along with subcellular localisation experiments and the results of functional genomic studies.

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“…The AsA and DHA contents were quantified as described previously (Tamaoki et al, 2003a). GSH and GSSG contents were measured as described by Yoshida et al (2006). All experiments were carried out in three replicates, each consisting of 20 to 30 pooled plants.…”

Section: In Vitro Treatments and In Situ Ros Detectionmentioning

confidence: 99%

Cooperative Ethylene and Jasmonic Acid Signaling Regulates Selenite Resistance in Arabidopsis

2008

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Selenium (Se) is an essential element for many organisms, but excess Se is toxic. To better understand plant Se toxicity and resistance mechanisms, we compared the physiological and molecular responses of two Arabidopsis (Arabidopsis thaliana) accessions, Columbia (Col)-0 and Wassilewskija (Ws)-2, to selenite treatment. Measurement of root length Se tolerance index demonstrated a clear difference between selenite-resistant Col-0 and selenite-sensitive Ws-2. Macroarray analysis showed more pronounced selenite-induced increases in mRNA levels of ethylene-or jasmonic acid (JA)-biosynthesis and -inducible genes in Col-0 than in Ws-2. Indeed, Col-0 exhibited higher levels of ethylene and JA. The selenite-sensitive phenotype of Ws-2 was attenuated by treatment with ethylene precursor or methyl jasmonate (MeJA). Conversely, the selenite resistance of Col-0 was reduced in mutants impaired in ethylene or JA biosynthesis or signaling. Genes encoding sulfur (S) transporters and S assimilation enzymes were up-regulated by selenite in Col-0 but not Ws-2. Accordingly, Col-0 contained higher levels of total S and Se and of nonprotein thiols than Ws-2. Glutathione redox status was reduced by selenite in Ws-2 but not in Col-0. Furthermore, the generation of reactive oxygen species by selenite was higher in Col-0 than in Ws-2. Together, these results indicate that JA and ethylene play important roles in Se resistance in Arabidopsis. Reactive oxygen species may also have a signaling role, and the resistance mechanism appears to involve enhanced S uptake and reduction.

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Cytosolic Dehydroascorbate Reductase is Important for Ozone Tolerance in Arabidopsisthaliana

Cited by 115 publications

References 21 publications

Cytosolic and Chloroplastic DHARs Cooperate in Oxidative Stress-Driven Activation of the Salicylic Acid Pathway

Cytosolic and Chloroplastic DHARs Cooperate in Oxidative Stress-Driven Activation of the Salicylic Acid Pathway

Glutathione Transferases

Cooperative Ethylene and Jasmonic Acid Signaling Regulates Selenite Resistance in Arabidopsis

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