PAL Activity and Differential Ozone Sensitivity in Tobacco, Bean and Poplar

Biagioni, Massimo; Nali, Cristina; Heimler, Daniela; Lorenzini, Giacomo

doi:10.1111/j.1439-0434.1997.tb00362.x

Cited by 17 publications

(6 citation statements)

References 26 publications

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“…Our results point out that in response to ozone one isoform of the DAHP synthase is earlier (1 h after onset of fumigation) induced and has an earlier maximum of induction than PAL on activity and transcript level reported in other studies (Biagioni et al 1997;Pasqualini et al 2003). This indicates that it might be necessary to induce DAHPS as a primary response for rerouting PEP and erythrose-4-phosphate (E-4-P; Fig.…”

Section: Discussionsupporting

confidence: 69%

Ozone has dramatic effects on the regulation of the prechorismate pathway in tobacco (Nicotiana tabacum L. cv. Bel W3)

Janzik

Preiskowski

Kneifel

2005

Planta

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The accumulation of aromatic secondary metabolites is a well-known element of the plant response to ozone. Most of these metabolites are synthesized via the three aromatic amino acids phenylalanine, tyrosine and tryptophan. Before branching, the biosynthetic pathway to the three amino acids shares seven enzymatic steps, called the prechorismate pathway, catalysed by 3-deoxy-D: -arabino-heptulosonate-7-phosphate (DAHP) synthase [EC 2.5.1.54], 3-dehydroquinate synthase [EC 4.2.3.4], 3-dehydroquinate dehydratase [EC 4.2.1.10]-shikimate 5-dehydrogenase [EC 1.1.1.25], shikimate kinase [EC 2.7.1.71], 5-enolpyruvylshikimate 3-phosphate synthase [EC 2.5.1.19] and chorismate synthase [EC 4.2.3.5]). We have studied the transcript level of these enzymes and the aromatic metabolite profile in the ozone sensitive tobacco cultivar BelW3 (Nicotiana tabacum L. cv Bel W3), when exposed to an acute ozone pulse (160 nl l(-1), 5 h). Specific cDNA-fragments of the corresponding six genes were isolated from tobacco Bel W3 and used as probes for determining the expression of the prechorismate pathway genes. The fully expanded leaves of ozone treated plants, which developed symptoms like necrotic leaf spots and accumulation of aromatic metabolites, showed a clear induction of the shikimate pathway genes; indicating, that this induction is linked to the development of the symptoms. Distinct kinetics and magnitudes were observed in tobacco leaves for the ozone dependent enhanced mRNA accumulation of the aforementioned genes in BelW3. The strongest and earliest induction due to ozone treatment could be observed for DAHP synthase. An isoform-specific analysis of the transcripts showed a strong induction on transcript level only for one of three isoforms, which was followed by the induction of the DAHP synthase also on protein level. The different induction kinetics of the prechorismate pathway genes indicate that their regulation in response to ozone might be regulated by different signals, for example, ethylene, reactive oxygen species or salicylic acid, which also occur with different kinetics and thus may play different roles in the plant response to ozone.

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Section: Discussionsupporting

confidence: 69%

Ozone has dramatic effects on the regulation of the prechorismate pathway in tobacco (Nicotiana tabacum L. cv. Bel W3)

Janzik

Preiskowski

Kneifel

2005

Planta

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“…Plant polyphenols can function as free radical scavengers (Larson 1988, Tamagnone et al 1998. Previous studies have shown that poplars exhibiting resistance to ozone-induced injury are characterized by an increase in polyphenols, such as chlorogenic acid in chloroplasts, which are known for their antioxidant properties (Biagioni et al 1997). Although the evidence for a direct contribution of plant polyphenols to the protection of mesophyll cells against oxidation resulting from severe water stress is equivocal, some of these compounds are lignin precursors and can participate in cell wall strengthening during drought (Niinemets 2001).…”

Section: Introductionmentioning

confidence: 99%

Physiological traits of two Populus x euramericana clones, Luisa Avanzo and Dorskamp, during a water stress and re-watering cycle

et al. 2002

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We compared responses to drought and re-watering of greenhouse-grown cuttings of Populus x euramericana (Dode) Guinier clones, Luisa Avanzo and Dorskamp. Total leaf area, leaf number, leaf area increment and stomatal conductance were evaluated periodically during a 29-day drought period and for 16 days after re-watering. Soil water content and predawn leaf water potential (Psi(wp)) were measured on Days 29 and 45. On the same days, relative water content (RWC), specific leaf area (SLA), nitrogen, chlorophyll, soluble sugars, total phenols, flavanols and antioxidant activity were determined for leaves taken from the bottom to the top of each cutting. Leaves of Luisa Avanzo cuttings grew more rapidly than leaves of Dorskamp and exhibited higher SLA, but lower concentrations of nitrogen, chlorophyll and soluble sugars and lower antioxidant activity per unit area. On Day 29, after withholding water, both clones had closed their stomata, reduced rates of leaf growth, and lower Psi(wp) and RWC; however, the clones differed in their responses to soil water depletion. Compared to Dorskamp, Luisa Avanzo closed its stomata earlier and maintained higher Psi(wp), but lower RWC and leaf sugar concentrations. Antioxidant activity of leaf methanolic extracts decreased in response to water stress only in Luisa Avanzo. Leaf physiology and its modulation by water stress were age dependent in Luisa Avanzo.

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“…Phenolic compounds are usually arranged in two groups—simple phenols (such as the cinnamic, p ‐coumaric, syringic and salicylic acids) and more complex molecules, often containing aromatic rings linked together (Kulbat, ). The aromatic 6‐C ring of phenolic compounds is synthesized in the shikimic acid pathway chiefly from the precursor amino acid phenylalanine, thanks to the action of phenylalanine ammonia‐lyase (PAL), an enzyme that since long has been demonstrated to play a crucial role in differential response of plants to O 3 (Biagioni, Nali, Heimler, & Lorenzini, ), although our knowledge on this topic is still scarce and fragmentary. Differently, phenolic variations in flooded plants have not been largely investigated.…”

Section: Introductionmentioning

confidence: 99%

Phenol metabolism of two cultivars of durum wheat (Triticum durum Desf.) as affected by ozone and flooding stress

Chen

Jha

et al. 2020

J Agronomy Crop Science

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To compare the phenolic responses under oxidative stressors, plants of two Italian cultivars of durum wheat (Claudio and Mongibello) were (a) exposed to ozone (O3) (80 ppb, 5 hr/day for 70 consecutive days), with the aim to investigate the changes of phenolic compound contents in their leaves, or (b) flooded (seven consecutive days). Plants showed O3‐induced visible injury, but their photosynthetic performance was not affected by the pollutant. Specifically, Claudio showed a higher O3 tolerance than Mongibello. The major value of the present study is undoubtedly the pioneering investigation of phenolic metabolism of durum wheat under O3. We identified 12 foliar phenolic compounds in all leaf samples (i.e. controls, exposed to O3 and flooded): ten phenolic acids, a flavanol (catechin hydrate) and a phenolic aldehyde (syringaldehyde). Overall, O3 exposure resulted in accumulations of phenolic compounds, especially in Claudio. These responses can be likely considered a fine‐regulated repair process that equipped Claudio stressed plants with an antioxidant system capable of scavenging oxidative stress. Different phenolic variations were found in flooded plants, suggesting that phenolic response to environmental constraints is stress specific. Our study confirms that investigations and characterization of specific phenolic profiles of crop cultivars under oxidative stress may be helpful in breeding programmes.

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PAL Activity and Differential Ozone Sensitivity in Tobacco, Bean and Poplar

Cited by 17 publications

References 26 publications

Ozone has dramatic effects on the regulation of the prechorismate pathway in tobacco (Nicotiana tabacum L. cv. Bel W3)

Ozone has dramatic effects on the regulation of the prechorismate pathway in tobacco (Nicotiana tabacum L. cv. Bel W3)

Physiological traits of two Populus x euramericana clones, Luisa Avanzo and Dorskamp, during a water stress and re-watering cycle

Phenol metabolism of two cultivars of durum wheat (Triticum durum Desf.) as affected by ozone and flooding stress

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