Identification of the Arabidopsis <i>dry2/sqe1‐5</i> mutant reveals a central role for sterols in drought tolerance and regulation of reactive oxygen species

Posé, David; Castanedo, Itziar; Borsani, Omar; Nieto, Benjamín; Rosado, Abel; Taconnat, Ludivine; Ferrer, Albert; Dolan, Liam; Valpuesta, Victoriano; Botella, Miguel A.

doi:10.1111/j.1365-313x.2009.03849.x

Cited by 116 publications

(115 citation statements)

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“…Inhibition of ethylene biosynthesis or signaling partially rescued fk, hyd1, and cyp51A2 mutants (Kim et al, 2010;Pullen et al, 2010). Sterols also can regulate the generation of reactive oxygen species, which play important roles in plant growth and cell death (Posé et al, 2009;Kim et al, 2010). A specific plant sterol biosynthetic intermediate (SBI) was speculated to have signaling functions.…”

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confidence: 99%

Sterol Methyl Oxidases Affect Embryo Development via Auxin-Associated Mechanisms

et al. 2016

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ORCID ID: 0000-0001-6472-6829 (S.M.).Sterols are essential molecules for multiple biological processes, including embryogenesis, cell elongation, and endocytosis. The plant sterol biosynthetic pathway is unique in the involvement of two distinct sterol 4a-methyl oxidase (SMO) families, SMO1 and SMO2, which contain three and two isoforms, respectively, and are involved in sequential removal of the two methyl groups at C-4. In this study, we characterized the biological functions of members of the SMO2 gene family. SMO2-1 was strongly expressed in most tissues during Arabidopsis (Arabidopsis thaliana) development, whereas SMO2-2 showed a more specific expression pattern. Although single smo2 mutants displayed no obvious phenotype, the smo2-1 smo2-2 double mutant was embryonic lethal, and the smo2-1 smo2-2/+ mutant was dwarf, whereas the smo2-1/+ smo2-2 mutant exhibited a moderate phenotype. The phenotypes of the smo2 mutants resembled those of auxin-defective mutants. Indeed, the expression of DR5 rev :GFP, an auxin-responsive reporter, was reduced and abnormal in smo2-1 smo2-2 embryos. Furthermore, the expression and subcellular localization of the PIN1 auxin efflux facilitator also were altered. Consistent with these observations, either the exogenous application of auxin or endogenous auxin overproduction (YUCCA9 overexpression) partially rescued the smo2-1 smo2-2 embryonic lethality. Surprisingly, the dwarf phenotype of smo2-1 smo2-2/+ was completely rescued by YUCCA9 overexpression. Gas chromatography-mass spectrometry analysis revealed a substantial accumulation of 4a-methylsterols, substrates of SMO2, in smo2 heterozygous double mutants. Together, our data suggest that SMO2s are important for correct sterol composition and function partially through effects on auxin accumulation, auxin response, and PIN1 expression to regulate Arabidopsis embryogenesis and postembryonic development.Sterols are isoprenoid-derived molecules that have diverse and essential functions in eukaryotes. Sterols are structural membrane components required for proper membrane permeability, fluidity, and membrane protein trafficking/localization. Silencing of the SQUALENE SYNTHASE1 gene compromised the resistance of tobacco (Nicotiana tabacum) to bacterial pathogens because of increased membrane leakage (Wang et al., 2012). Disturbed membrane sterol composition in the Arabidopsis (Arabidopsis thaliana) cyclopropylsterol isomerase1-1 (cpi1-1) mutant affected the polar localization of the PIN2 auxin efflux protein and the cell plate distribution of KNOLLE syntaxin by inhibiting the endocytosis of these proteins (Men et al., 2008;Boutté et al., 2010). Moreover, sterol-enriched plasma membrane microdomains (lipid rafts) have been proposed to act as signaling platforms (Mongrand et al., 2004(Mongrand et al., , 2010Martin et al., 2005).Plant sterols are precursors for the biosynthesis of brassinosteroids (BRs), a group of phytohormones that are essential for plant growth and development. However, increasing evidence indicates that plant ster...

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confidence: 99%

Sterol Methyl Oxidases Affect Embryo Development via Auxin-Associated Mechanisms

et al. 2016

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“…4) participates in phenylpropanoid biosynthesis and its derivatives are involved in cell wall strengthening and cell division (Mader and Hanke, 1997). Furthermore, low HMG-CoA synthase levels may lead to misregulation of growth, development and respiration (Posé et al, 2009). Our result showed that high NH4 + concentration in the growing medium led to a decrease in the abundance of HMG-CoA synthase, implying that NH4 + toxicity might block the biosynthesis of cell wall components in roots.…”

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confidence: 48%

Physiological Response and Comparative Proteomic Analysis of Tobacco Seedling Roots to NH4+

Tan¹

2017

IJAB

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Plants absorb nitrogen, an essential element for their growth and development, mainly in the form of nitrate or ammonium. These nitrogen species have different effects on crops, little is known about their precise influence at both physiological and proteomic levels. This study investigated these mechanisms, hydroponically grown tobacco seedlings treated with three different ratios of NO3 -to NH4 + (10:0, 5:5 or 0:10) for 15 days. The results showed that exposure to high NH4 + concentration affected root morphology and inhibited root development. Moreover, malondialdehyde content and the activity of glutamine synthetase, superoxide dismutase, peroxidase and glutathione S-transferase increased with the concentration of NH4 + in solution. Two-dimensional protein gel analysis showed that 40 protein were differentially expressed between the three treatments. 36 of these proteins were identified using liquid chromatography-mass spectrometry/mass spectrometry (LC-MS/MS). Gene ontology analysis indicated that these proteins were involved in metabolism, energy production, cell defense or signal transduction or structural constituents related pathways. Our results suggest that tobacco seedling roots are subjected to NH4 + toxicity that triggers oxidative stress. Our results help understanding the responses to different nitrogen species and to NH4 + toxicity in roots.

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“…In addition to enzymatic ROS detoxification, hydrophilic and lipophilic antioxidant compounds contribute to the antioxidant response and may serve as radical scavengers (Fryer, 1992;Loreto et al, 2001;Larkindale and Huang, 2004;Pose et al, 2009). Increased levels of such compounds assist for a rapid detoxification of ROS and aid the protection of subcellular structures.…”

Section: Accumulation and Detoxification Of Reactive Oxygen Speciesmentioning

confidence: 99%

Extreme climatic events: impacts of drought and high temperature on physiological processes in agronomically important plants

Feller

Vaseva

2014

Front. Environ. Sci.

103

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Climate models predict more frequent and more severe extreme events (e.g., heat waves, extended drought periods, flooding) in many regions for the next decades. The impact of adverse environmental conditions on crop plants is ecologically and economically relevant. This review is focused on drought and heat effects on physiological status and productivity of agronomically important plants. Stomatal opening represents an important regulatory mechanism during drought and heat stress since it influences simultaneously water loss via transpiration and CO 2 diffusion into the leaf apoplast which further is utilized in photosynthesis. Along with the reversible short-term control of stomatal opening, stomata and leaf epidermis may produce waxy deposits and irreversibly down-regulate the stomatal conductance and non-stomatal transpiration. As a consequence photosynthesis will be negatively affected. Rubisco activase-a key enzyme in keeping the Calvin cycle functional-is heat-sensitive and may become a limiting factor at elevated temperature. The accumulated reactive oxygen species (ROS) during stress represent an additional challenge under unfavorable conditions. Drought and heat cause accumulation of free amino acids which are partially converted into compatible solutes such as proline. This is accompanied by lower rates of both nitrate reduction and de novo amino acid biosynthesis. Protective proteins (e.g., dehydrins, chaperones, antioxidant enzymes or the key enzyme for proline biosynthesis) play an important role in leaves and may be present at higher levels under water deprivation or high temperatures. On the whole plant level, effects on long-distance translocation of solutes via xylem and phloem and on leaf senescence (e.g., anticipated, accelerated or delayed senescence) are important. The factors mentioned above are relevant for the overall performance of crops under drought and heat and must be considered for genotype selection and breeding programs.

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Identification of the Arabidopsis dry2/sqe1‐5 mutant reveals a central role for sterols in drought tolerance and regulation of reactive oxygen species

Cited by 116 publications

References 63 publications

Sterol Methyl Oxidases Affect Embryo Development via Auxin-Associated Mechanisms

Sterol Methyl Oxidases Affect Embryo Development via Auxin-Associated Mechanisms

Physiological Response and Comparative Proteomic Analysis of Tobacco Seedling Roots to NH4+

Extreme climatic events: impacts of drought and high temperature on physiological processes in agronomically important plants

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