Proton pumping by tomato roots. Effect of Fe deficiency and hormones on the activity and distribution of plasma membrane H<sup>+</sup>‐ATPase in rhizodermal cells

Schmidt, Wolfgang; Michalke, W.; Schikora, Adam

doi:10.1046/j.1365-3040.2003.00967.x

Cited by 51 publications

(46 citation statements)

References 62 publications

(87 reference statements)

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“…As reported for ferric/ferricyanide reductases in microalgae and plants, 54,56,60,61 PCC7942 caused extracellular acidication in unbuffered media, as a consequence of extracellular electron transport to ferricyanide (Fig. 5).…”

supporting

confidence: 69%

Tapping into cyanobacteria electron transfer for higher exoelectrogenic activity by imposing iron limited growth

et al. 2018

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The exoelectrogenic capacity of the cyanobacterium Synechococcus elongatus PCC7942 was studied in iron limited growth in order to establish conditions favouring extracellular electron transfer in cyanobacteria for photo-bioelectricity generation. Investigation into extracellular reduction of ferricyanide by Synechococcus elongatus PCC7942 demonstrated enhanced capability for the iron limited conditions in comparison to the iron sufficient conditions. Furtheremore, the significance of pH showed that higher rates of ferricyanide reduction occurred at pH 7, with a 2.7-fold increase with respect to pH 9.5 for iron sufficient cultures and 24-fold increase for iron limited cultures. The strategy presented induced exoelectrogenesis driven mainly by photosynthesis and an estimated redirection of the 28% of electrons from photosynthetic activity was achieved by the iron limited conditions. In addition, ferricyanide reduction in the dark by iron limited cultures also presented a significant improvement, with a 6-fold increase in comparison to iron sufficient cultures. Synechococcus elongatus PCC7942 ferricyanide reduction rates are unprecedented for cyanobacteria and they are comparable to those of microalgae. The redox activity of biofilms directly on ITO-coated glass, in the absence of any artificial mediator, was also enhanced under the iron limited conditions, implying that iron limitation increased exoelectrogenesis at the outer membrane level. Cyclic voltammetry of Synechococcus elongatus PCC7942 biofilms on ITO-coated glass showed a midpoint potential around 0.22 V vs. Ag/ AgCl and iron limited biofilms had the capability to sustain currents in a saturated-like fashion. The present work proposes an iron related exoelectrogenic capacity of Synechococcus elongatus PCC7942 and sets a starting point for the study of this strain in order to improve photo-bioelectricity and darkbioelectricity generation by cyanobacteria, including more sustainable mediatorless systems.

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supporting

confidence: 69%

Tapping into cyanobacteria electron transfer for higher exoelectrogenic activity by imposing iron limited growth

et al. 2018

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“…In addition, secretion of iron binding compounds (IBCs) facilitates the mobilization of iron particularly at high pH (Susín et al, 1993; Jin et al, 2007; Fourcroy et al, 2013; Rodríguez-Celma et al,2013). A further set of supposedly separately regulated responses comprise morphological changes such as the formation of additional root hairs and invaginations of secondary walls in the rhizodermis/hypodermis, responses that were suggested to improve iron acquisition by increasing the absorptive surface area (Schikora and Schmidt, 2001; Schmidt et al, 2003). In contrast to phosphate deficiency, which triggers a nutrient-specific and conserved set of developmental responses including denser and longer root hairs (Ma et al, 2001; Savage et al, 2013) and a dramatically altered root architecture where primary root growth is attenuated and lateral root formation is stimulated (Ticconi et al, 2009), the morphological responses to iron deficiency are less well studied and appear to be less conserved among species.…”

Section: Introductionmentioning

confidence: 99%

Functional implications of K63-linked ubiquitination in the iron deficiency response of Arabidopsis roots

Pan

Schmidt

2014

Front. Plant Sci.

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Iron is an essential micronutrient that plays important roles as a redox cofactor in a variety of processes, many of which are related to DNA metabolism. The E2 ubiquitin conjugase UBC13, the only E2 protein that is capable of catalyzing the formation of non-canonical K63-linked ubiquitin chains, has been associated with the DNA damage tolerance pathway in eukaryotes, critical for maintenance of genome stability and integrity. We previously showed that UBC13 and an interacting E3 ubiquitin ligase, RGLG, affect the differentiation of root epidermal cells in Arabidopsis. When grown on iron-free media, Arabidopsis plants develops root hairs that are branched at their base, a response that has been interpreted as an adaption to reduced iron availability. Mutations in UBC13A abolished the branched root hair phenotype. Unexpectedly, mutations in RGLG genes caused constitutive root hair branching. Based on recent results that link endocytotic turnover of plasma membrane-bound PIN transporters to K63-linked ubiquitination, we reinterpreted our results in a context that classifies the root hair phenotype of iron-deficient plants as a consequence of altered auxin distribution. We show here that UBC13A/B and RGLG1/2 are involved in DNA damage repair and hypothesize that UBC13 protein becomes limited under iron-deficient conditions to prioritize DNA metabolism. The data suggest that genes involved in combating detrimental effects on genome stability may represent essential components in the plant’s stress response.

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“…A split-root system (Schortemeyer et al 1993;Cramer and Lewis 1993;Chaillou et al 1994;Feil 1994;Schortemeyer and Feil 1996) was developed to study the response of plants to a simultaneous but spatially separated supply of NO 3 − and NH 4 + , in which half of the root system is exposed to NO 3 − only and the other half to NH 4 + only. This system is acknowledged as being superior to the homogeneous system to study the effects of different N forms on physiological and molecular responses (Chaillou et al 1994;Walch-Liu et al 2000Gansel et al 2001;Guo et al 2002Guo et al , 2007Schmidt et al 2003;Rahayu et al 2005;Boukcima et al 2006). Chaillou et al (1994) used the split-root system to study independent uptake of NO 3 − or NH 4 + , since it was difficult to assess the quantitative effects on assimilate partitioning when the two ions were supplied in combination.…”

Section: Introductionmentioning

confidence: 99%

Effects of different nitrogen forms on the growth and cytokinin content in xylem sap of tomato (Lycopersicon esculentum Mill.) seedlings

Shen

et al. 2008

Plant Soil

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In order to investigate the effects of homogeneous and localized supply of different nitrogen forms (nitrate, NO 3 − vs ammonium, NH 4 + ) on the growth of tomato seedlings, root morphology and six cytokinin (CTK) fractions in xylem sap were analyzed. Whole roots were supplied with different ratios of NO 3 − to NH 4 + (100:0, as 100-0NA; 75:25, as 75-25NA; 50:50, as 50-50NA) under homogeneous supply. In split-root experiments, three treatments were compared: a sole NO 3 − supply (N|N), a spatially separated supply of NO 3 − and NH 4 + (N|A), and a spatially separated supply of NO 3 − and a mixture of NO 3 − and NH 4 + nutrition at a ratio of 75:25 (N|AN). All concentrations of total N were set at 5 mM. The results showed that (1) homogeneous 75% NO 3 − plus 25% NH 4 + supply to the whole root zone led to maximum shoot and root dry matter (DM), root surface area (RS) and root volume (RV). The spatially separated supply of NO 3 − and NH 4 + (N|A) resulted in a contrasting effect on root morphology: in comparison to N|N, root DM in the NO 3 − -containing pot was increased by 50% whereas it was depressed by 50% in the NH 4 + -containing pot. The 75% NO 3 − plus 25%NH 4 + supply in the split-root experiment led to no significant effects either on shoot DM and root DM, or on RS and RV when compared to N|N. (2) The presence of NH 4 + in the external medium led to a significantly reduced total xylem-CTK concentration, and a close negative correlation was found between xylem NH 4 + and total CTK concentration irrespective of culture mode. A relatively high level of zeatin riboside (ZR) was maintained both in 75-25NA and N|A treatments. It was concluded that, in addition to the percentage of NH 4 + to NO 3 − in the nutrient solution, whether NH 4 + was supplied to the whole root system or to only part of the root system was also an important factor affecting plant growth. The fact that the 75-25NA and N|A treatments resulted in optimal growth of tomato seedlings might be attributed to the higher ZR concentration in xylem.

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Proton pumping by tomato roots. Effect of Fe deficiency and hormones on the activity and distribution of plasma membrane H⁺‐ATPase in rhizodermal cells

Cited by 51 publications

References 62 publications

Tapping into cyanobacteria electron transfer for higher exoelectrogenic activity by imposing iron limited growth

Tapping into cyanobacteria electron transfer for higher exoelectrogenic activity by imposing iron limited growth

Functional implications of K63-linked ubiquitination in the iron deficiency response of Arabidopsis roots

Effects of different nitrogen forms on the growth and cytokinin content in xylem sap of tomato (Lycopersicon esculentum Mill.) seedlings

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Proton pumping by tomato roots. Effect of Fe deficiency and hormones on the activity and distribution of plasma membrane H+‐ATPase in rhizodermal cells

Cited by 51 publications

References 62 publications

Tapping into cyanobacteria electron transfer for higher exoelectrogenic activity by imposing iron limited growth

Tapping into cyanobacteria electron transfer for higher exoelectrogenic activity by imposing iron limited growth

Functional implications of K63-linked ubiquitination in the iron deficiency response of Arabidopsis roots

Effects of different nitrogen forms on the growth and cytokinin content in xylem sap of tomato (Lycopersicon esculentum Mill.) seedlings

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Proton pumping by tomato roots. Effect of Fe deficiency and hormones on the activity and distribution of plasma membrane H⁺‐ATPase in rhizodermal cells