The eto1, eto2, and eto3 Mutations and Cytokinin Treatment Increase Ethylene Biosynthesis in Arabidopsis by Increasing the Stability of ACS Protein

Chae, Hyun Sook; Fauré, François; Kieber, Joseph J.

doi:10.1105/tpc.006882

Cited by 340 publications

(416 citation statements)

References 41 publications

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“…DPBA fluorescence was examined in the ethylene-overproducing1 (eto1) mutant (Chae et al, 2003) and enhanced flavonol accumulation was observed in the guard cells (Fig. 2).…”

Section: Elevated Ethylene Levels Through Exogenous Treatment or In Tmentioning

confidence: 99%

Ethylene-Induced Flavonol Accumulation in Guard Cells Suppresses Reactive Oxygen Species and Moderates Stomatal Aperture

2014

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Guard cell swelling controls the aperture of stomata, pores that facilitate gas exchange and water loss from leaves. The hormone abscisic acid (ABA) has a central role in regulation of stomatal closure through synthesis of second messengers, which include reactive oxygen species (ROS). ROS accumulation must be minimized by antioxidants to keep concentrations from reaching damaging levels within the cell. Flavonols are plant metabolites that have been implicated as antioxidants; however, their antioxidant activity in planta has been debated. Flavonols accumulate in guard cells of Arabidopsis thaliana, but not surrounding pavement cells, as visualized with a flavonolspecific dye. The expression of a reporter driven by the promoter of CHALCONE SYNTHASE, a gene encoding a flavonol biosynthetic enzyme, in guard cells, but not pavement cells, suggests guard cell-specific flavonoid synthesis. Increased levels of ROS were detected using a fluorescent ROS sensor in guard cells of transparent testa4-2, which has a null mutation in CHALCONE SYNTHASE and therefore synthesizes no flavonol antioxidants. Guard cells of transparent testa4-2 show more rapid ABA-induced closure than the wild type, suggesting that flavonols may dampen the ABA-dependent ROS burst that drives stomatal closing. The levels of flavonols are positively regulated in guard cells by ethylene treatment in the wild type, but not in the ethylene-insensitive2-5 mutant. In addition, in both ethyleneoverproducing1 and ethylene-treated wild-type plants, elevated flavonols lead to decreasing ROS and slower ABA-mediated stomatal closure. These results are consistent with flavonols suppressing ROS accumulation and decreasing the rate of ABA-dependent stomatal closure, with ethylene-induced increases in guard cell flavonols modulating these responses.

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“…DPBA fluorescence was examined in the ethylene-overproducing1 (eto1) mutant (Chae et al, 2003) and enhanced flavonol accumulation was observed in the guard cells (Fig. 2).…”

Section: Elevated Ethylene Levels Through Exogenous Treatment or In Tmentioning

confidence: 99%

Ethylene-Induced Flavonol Accumulation in Guard Cells Suppresses Reactive Oxygen Species and Moderates Stomatal Aperture

2014

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“…The respective GST fusion proteins were isolated using Glutathione Sepharose 4 Fast Flow medium according to the manufacturer's directions (Amersham Biosciences). ACS5 was purified as described (Chae et al, 2003). Myelin basic protein was purchased from Sigma-Aldrich.…”

Section: Protein Kinase Assaysmentioning

confidence: 99%

Two Leucine-Rich Repeat Receptor Kinases Mediate Signaling, Linking Cell Wall Biosynthesis and ACC Synthase in Arabidopsis

et al. 2008

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The plant cell wall is a dynamic structure that changes in response to developmental and environmental cues through poorly understood signaling pathways. We identified two Leu-rich repeat receptor-like kinases in Arabidopsis thaliana that play a role in regulating cell wall function. Mutations in these FEI1 and FEI2 genes (named for the Chinese word for fat) disrupt anisotropic expansion and the synthesis of cell wall polymers and act additively with inhibitors or mutations disrupting cellulose biosynthesis. While FEI1 is an active protein kinase, a kinase-inactive version of FEI1 was able to fully complement the fei1 fei2 mutant. The expansion defect in fei1 fei2 roots was suppressed by inhibition of 1-aminocyclopropane-1-carboxylic acid (ACC) synthase, an enzyme that converts Ado-Met to ACC in ethylene biosynthesis, but not by disruption of the ethylene response pathway. Furthermore, the FEI proteins interact directly with ACC synthase. These results suggest that the FEI proteins define a novel signaling pathway that regulates cell wall function, likely via an ACC-mediated signal.

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“…At 32°C, exogenous auxin (NAA) and cytokinin (BAP) and endogenously produced ethylene are all required for cell survival (Roberts et al, 1995;Gushwa et al, 2003). We speculate that NAA and BAP are both required for survival at 32°C because cytokinin stabilizes the 1-aminocyclopropane-carboxylic acid synthase (ACS) protein (Chae et al, 2003) that results from auxin-mediated induction of ACS genes (Abel et al, 1995;Abel and Theologis, 1996;Merritt et al, 2001;Tanaka et al, 2006), thereby optimizing ethylene production required for protoplast survival at 32°C. After 24 h of preincubation at 38°C, none of these growth regulators are required for GCP to survive in culture at 32°C (Gushwa et al, 2003).…”

Section: Discussionmentioning

confidence: 99%

Heat Suppresses Activation of an Auxin-Responsive Promoter in Cultured Guard Cell Protoplasts of Tree Tobacco

et al. 2007

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Cultured guard cell protoplasts (GCP) of tree tobacco (Nicotiana glauca) comprise a novel system for investigating the cell signaling mechanisms that lead to acquired thermotolerance and thermoinhibition. At 32°C in a medium containing an auxin (1-naphthaleneacetic acid [NAA]) and a cytokinin (6-benzylaminopurine), GCP expand, regenerate cell walls, dedifferentiate, and divide. At 38°C, GCP acquire thermotolerance within 24 h, but their expansion is limited and they neither regenerate walls nor reenter the cell cycle. These putative indicators of auxin insensitivity led us to hypothesize that heat suppresses induction of auxin-regulated genes in GCP. Protoplasts were transformed with BA-mgfp5-ER, in which the BA auxin-responsive promoter regulates transcription of mgfp5-ER encoding thermostable green fluorescent protein (GFP) or with a similar 35S-cauliflower mosaic virus constitutive promoter construct. Heat suppressed NAA-mediated activation of BA. After 21 h at 32°C in media with NAA, 49.0% 6 3.9% of BA-mgfp5-ER transformants strongly expressed GFP; expression percentages were similar to those of 35S-mgfp5-ER transformants at 32°C or 38°C. After 21 h at 38°C in media with NAA, 7.9% 6 1.6% of BA-mgfp5-ER transformants weakly expressed GFP, similar to GCP cultured at 32°C in media lacking NAA. Expression at 38°C was not increased by incubating for 48 h or increasing NAA concentrations 20-fold. After 9 to 12 h at 38°C, BA was no longer activated when cells were transferred to 32°C. Heat-stressed cells accumulate reactive oxygen species, and hydrogen peroxide (H 2 O 2 ) suppresses auxin-responsive promoter activation in Arabidopsis (Arabidopsis thaliana) mesophyll protoplasts. H 2 O 2 did not suppress BA activation at 32°C, nor did superoxide and H 2 O 2 scavengers prevent BA suppression at 38°C.

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The eto1, eto2, and eto3 Mutations and Cytokinin Treatment Increase Ethylene Biosynthesis in Arabidopsis by Increasing the Stability of ACS Protein

Cited by 340 publications

References 41 publications

Ethylene-Induced Flavonol Accumulation in Guard Cells Suppresses Reactive Oxygen Species and Moderates Stomatal Aperture

Ethylene-Induced Flavonol Accumulation in Guard Cells Suppresses Reactive Oxygen Species and Moderates Stomatal Aperture

Two Leucine-Rich Repeat Receptor Kinases Mediate Signaling, Linking Cell Wall Biosynthesis and ACC Synthase in Arabidopsis

Heat Suppresses Activation of an Auxin-Responsive Promoter in Cultured Guard Cell Protoplasts of Tree Tobacco

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