Correlation between Root-Generated Ionic Currents, pH, Fusicoccin, Indoleacetic Acid, and Growth of the Primary Root of <i>Zea mays</i>

Miller, Andrew L.; Gow, Neil A. R.

doi:10.1104/pp.89.4.1198

Cited by 52 publications

(48 citation statements)

References 35 publications

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“…In brief, anthers were dissected from several inflorescences and kept in artificial pond water (Miller and Gow, 1989) until further use. PMCs were released from anthers and collected in a small volume of artificial pond water (Chen et al, 2010 (Albini et al, 1984), and meiocytes were incubated for 5 min at room temperature.…”

Section: Cytologymentioning

confidence: 99%

The Recombinases DMC1 and RAD51 Are Functionally and Spatially Separated during Meiosis in Arabidopsis

et al. 2012

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Meiosis ensures the reduction of the genome before the formation of generative cells and promotes the exchange of genetic information between homologous chromosomes by recombination. Essential for these events are programmed DNA double strand breaks (DSBs) providing single-stranded DNA overhangs after their processing. These overhangs, together with the RADiation sensitive51 (RAD51) and DMC1 Disrupted Meiotic cDNA1 (DMC1) recombinases, mediate the search for homologous sequences. Current models propose that the two ends flanking a meiotic DSB have different fates during DNA repair, but the molecular details remained elusive. Here we present evidence, obtained in the model plant Arabidopsis thaliana, that the two recombinases, RAD51 and DMC1, localize to opposite sides of a meiotic DSB. We further demonstrate that the ATR kinase is involved in regulating DMC1 deposition at meiotic DSB sites, and that its elimination allows DMC1-mediated meiotic DSB repair even in the absence of RAD51. DMC1's ability to promote interhomolog DSB repair is not a property of the protein itself but the consequence of an ASYNAPTIC1 (Hop1)-mediated impediment for intersister repair. Taken together, these results demonstrate that DMC1 functions independently and spatially separated from RAD51 during meiosis and that ATR is an integral part of the regular meiotic program.

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Section: Cytologymentioning

confidence: 99%

The Recombinases DMC1 and RAD51 Are Functionally and Spatially Separated during Meiosis in Arabidopsis

et al. 2012

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“…The significance of these gradients in relation to plant root growth has been discussed previously (Raven & Smith, 1974;Verse1 & Mayor, 1985;Rathore & Goldsworthy, 1985a, b;Toko e t al., 1989Toko e t al., ,1990Behrens et al, 1982;Bjorkman & Leopold, 1987a, b;Miller & Gow, 1989a). Zoospores may sense electrical fields that are the result of these proton circulations and use them for guidance towards the root surface (Miller et al, 1988;Gow et al, 1992;Morris et al, 1992;Morris & Gow, 1993;Gow, 1993).…”

Section: Current Flow Establishes Voltage Ionic and Ph Gradientsmentioning

confidence: 99%

Tactic response of zoospores of the fungus Phytophthora palmivora to solutions of different pH in relation to plant infection

1995

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Zoospores of the plant pathogen Phytophthora palmivora use a number of tactic responses to target specific infectible regions of host roots. Although the dominant one is believed to be chemotaxis, it has been shown that zoospores of oomycetes may also use the exogenous protonlelectrical currents generated by plant roots for guidance. Since these proton currents also generate significant pH gradients in the rhizosphere, the tactic response of zoospores to changes in pH was examined. Using 'swim-in' capillary tests, zoospores of P. palmiwora were found to be repelled by solutions of high pH and attracted to solutions of low pH, relative to a control at neutrality. This in vitro tactic response was generally consistent with the measured pH a t sites of zoospore accumulation around intact and wounded roots. However, the endogenous pH gradient around host roofs could be abolished with buffers and this treatment did not affect the extent or pattern of zoospore accumulation. Therefore, detection of root-generated pH gradients is unlikely to have a major role in the homing response of zoospores towards plant roots.

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“…Net current enters the root apex (root cap, meristem, and part of the elongation zone) and leaves through the mature tissue. In roots of Zea mays, Miller and Gow (21) found that treatments that stimulated root growth (low pH, fusicoccin) were associated with an increase in the inward current at the root tip and elongation zones, whereas treatments that inhibited root growth (high pH, IAA) reduced the current magnitude. Furthermore, Miller et al (23) showed that localized areas of inward current were associated with sites of emerging lateral roots.…”

mentioning

confidence: 99%

Aluminum Toxicity in Roots

Ryan

Shaff²,

Kochian³

1992

Plant Physiol.

108

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The inhibition of root growth by aluminum (Al) is well established, yet a unifying mechanism for Al toxicity remains unclear.The association between cell growth and endogenously generated ionic currents measured in many different systems, including plant roots, suggests that these currents may be directing growth. A vibrating voltage microelectrode system was used to measure the net ionic currents at the apex of wheat (Triticum aestivum L.) roots from Al-tolerant and Al-sensitive cultivars. We examined the relationship between these currents and Al-induced inhibition of root growth. In the Al-sensitive cultivar, Scout 66, 10 micromolar Al (pH 4.5) began to inhibit the net current and root elongation within 1 to 3 hours. These changes occurred concurrently in 75% of experiments. A significant correlation was found between current magnitude and the rate of root growth when data were pooled. No changes in either current magnitude or growth rate were observed in similar experiments using the Al-tolerant cultivar Atlas 66. Measurements with ion-selective microelectrodes suggested that H' influx was responsible for most of the current at the apex, with smaller contributions from Ca2" and Cl fluxes. In 50% of experiments, Al began to inhibit the net Ho influx in Scout 66 roots at the same time that growth was affected. However, in more than 25% of cases, Al-induced inhibition of growth rate occurred before any sustained decrease in the current or H' flux. Although showing a correlation between growth and current or H' fluxes, these data do not suggest a mechanistic association between these processes.We conclude that the inhibition of root growth by Al is not caused by the reduction in current or H' influx at the root apex.Al2 toxicity has been identified as one of the most important factors limiting plant growth in acid soils (5). Although a wide range of Al-related effects have been described in plants ' P.R.R.

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Correlation between Root-Generated Ionic Currents, pH, Fusicoccin, Indoleacetic Acid, and Growth of the Primary Root of Zea mays

Cited by 52 publications

References 35 publications

The Recombinases DMC1 and RAD51 Are Functionally and Spatially Separated during Meiosis in Arabidopsis

The Recombinases DMC1 and RAD51 Are Functionally and Spatially Separated during Meiosis in Arabidopsis

Tactic response of zoospores of the fungus Phytophthora palmivora to solutions of different pH in relation to plant infection

Aluminum Toxicity in Roots

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