Mannitol metabolism in plants: a method for coping with stress

Stoop, J. M. H.; Williamson, John D.; Pharr, D. M.

doi:10.1016/s1360-1385(96)80048-3

Cited by 335 publications

(252 citation statements)

References 38 publications

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“…Mannitol catabolism is restricted to actively growing sink tissues in celery (Fellman and Loescher, 1987), and the presence of MTD activity is correlated with the ability of these tissues to catabolize mannitol Pharr, 1992, 1994a, 199413). MTD may be expressed in these actively growing tissues because they have very low hexose pools due to their high energy and carbon demands (Stoop and Pharr, 1992, 199413;Stoop et al, 1996). In celery plants transferred to darkness, sugars are metabolized before mannitol (Fellman and Loescher, 1987).…”

Section: Discussionmentioning

confidence: 99%

“…Sugar repression of MTD may allow celery plants to store large amounts of mannitol while preferentially using sugars for metabolism. This is important in stress tolerance in celery, in which mannitol functions as an osmoprotectant (Stoop et al, 1996). Conservation of mannitol as a storage reserve for later use also may be critical to reproductive growth in this biennial plant.…”

Section: Discussionmentioning

confidence: 99%

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Sugar Repression of Mannitol Dehydrogenase Activity in Celery Cells

et al. 1997

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We present evidence that the activity of the mannitolcatabolizing enzyme mannitol dehydrogenase (MTD) is repressed by sugars in cultured celery (Apium graveolens L.) cells. Furthermore, this sugar repression appears to be mediated by hexokinases (HKs) in a manner comparable to the reported sugar repression of photosynthetic genes. Glucose (Glc)-grown cell cultures expressed little MTD activity during active growth, but underwent a marked increase in MTD activity, protein, and RNA upon Clc starvation. Replenishment of Glc in the medium resulted in decreased MTD activity, protein, and RNA within 12 h. Addition of mannoheptulose, a competitive inhibitor of HK, derepressed MTD activity in Glc-grown cultures. In contrast, the addition of the sugar analog 2-deoxyglucose, which is phosphorylated by HK but not further metabolized, repressed MTD activity in mannitol-grown cultures. Collectively, these data suggest that HK and sugar phosphorylation are involved in signaling MTD repression. In vivo repression of MTD activity by galactose (Cal), which is not a substrate of HK, appeared to be an exception to this hypothesis. Further analyses, however, showed that the products of Cal catabolism, Glc and fructose, rather than Cal itself, were correlated with MTD repression.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Sugar Repression of Mannitol Dehydrogenase Activity in Celery Cells

et al. 1997

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“…However, different types of plants show different responses to these salt-induced injurious effects (Ashraf & Foolad 2007;Ashraf 2009). One of the premier responses of plants to salinity is the synthesis and accumulation of compatible organic substances including amino acids, especially proline (Thomas et al 1992;Ashraf & Foolad 2007;Ashrafijou et al 2010), quaternary ammonium compounds (Ashraf & Foolad 2007;Geng et al 2011), organic acids (Chen et al 2009;Farouk 2011), and polyols such as sorbitol and mannitol (Stoop et al 1996;Mitoi et al 2009). All these osmotically active organic solutes play a key role in osmotic adjustment, a phenomenon which has been widely reported to play an active role in maintaining cell turgor (Galinski 1995;Siringam et al 2011).…”

Section: Introductionmentioning

confidence: 99%

Exogenous application of mannitol and thiourea regulates plant growth and oxidative stress responses in salt-stressed maize (Zea maysL.)

Kaya

Sönmez

Aydemir

et al. 2013

Journal of Plant Interactions

103

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The mechanism of growth amelioration in salt-stressed maize (Zea mays L. cv., DK 647 F1) by exogenously applied mannitol (M) and thiourea (T) was investigated. Maize seedlings were planted in pots containing perlite and subjected to 0 or 100 mM NaCl in full strength Hoagland's nutrient solution. Two levels of M (15 and 30 mM) or T (3.5 and 7.0 mM) were sprayed to the leaves of maize seedlings 10 days after germination. Salinity stress caused considerable reduction in plant dry biomass, chlorophyll content, and relative water content in the maize plants. However, it increased the activities of catalase (CAT; EC 1.11.1.6), superoxide dismutase (SOD; EC 1.15.1.1), and polyphenol oxidase (PPO; EC 1.10.3.1), and levels of hydrogen peroxide (H 2 O 2 ) and electrolyte leakage, but it did not change peroxidase (POD; EC 1.11.1.7) activity. Foliar application of M or T was found to be effective in checking salt-induced shoot growth inhibition. Exogenously applied M or T reduced the activities of CAT, SOD, POD, and PPO in the salt-treated maize plants compared to those in the plants not fed with these organic compounds. Salinity increased Na ' contents but decreased those of K ' , Ca 2 ' , and P in the leaves and roots of the maize plants. Foliar-applied M or T increased the contents of K ' , Ca 2 ' , and P, but decreased that of Na ' in the salt-stressed maize plants with respect to those of the salt-stressed plants not supplied with mannitol or thiourea. Mannitol was found to be more effective than thiourea in improving salinity tolerance of maize plants in terms of growth and physiological attributes measured in the present study.

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“…The hexitol D-mannitol is accumulated by vascular plants (37) and many fungal species (21). In A. niger conidiospores, D-mannitol is the predominant carbon-containing compound and makes up 10 to 15% of the dry weight (41).…”

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confidence: 99%

Mannitol Is Required for Stress Tolerance inAspergillus nigerConidiospores

et al. 2003

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D-Mannitol is the predominant carbon compound in conidiospores of the filamentous fungus Aspergillus niger and makes up 10 to 15% of the dry weight. A number of physiological functions have been ascribed to mannitol, including serving as a reserve carbon source, as an antioxidant, and to store reducing power. In this study, we cloned and characterized the A. niger mpdA gene, which encodes mannitol 1-phosphate dehydrogenase (MPD), the first enzyme in the mannitol biosynthesis pathway. The mpdA promoter contains putative binding sites for the development-specific transcription factors BRLA and ABAA. Furthermore, increased expression of mpdA in sporulating mycelium suggests that mannitol biosynthesis is, to a certain extent, developmentally regulated in A. niger. Inactivation of mpdA abolished mannitol biosynthesis in growing mycelium and reduced the mannitol level in conidiospores to 30% that in the wild type, indicating that MPD and mannitol 1-phosphate phosphatase form the major metabolic pathway for mannitol biosynthesis in A. niger. The viability of spores after prolonged storage and germination kinetics were normal in an mpdA null mutant, indicating that mannitol does not play an essential role as a reserve carbon source in A. niger conidia. However, conidiospores of a ⌬mpdA strain were extremely sensitive to a variety of stress conditions, including high temperature, oxidative stress and, to a lesser extent, freezing and lyophilization. Since mannitol supplied in the medium during sporulation repaired this deficiency, mannitol appears to be essential for the protection of A. niger spores against cell damage under these stress conditions. Polyols or polyhydroxyalcohols are present in all organisms, from bacteria to animals. In particular, plants and fungi are known to accumulate high levels of polyols intracellularly, up to several hundred millimoles per liter. The filamentous fungus Aspergillus niger produces a number of different polyols, including glycerol, erythritol, and D-mannitol (41). The intracellular concentrations of the individual polyols in A. niger depend on growth conditions and developmental stage, suggesting that polyols have important functions in fungal physiology.The hexitol D-mannitol is accumulated by vascular plants (37) and many fungal species (21). In A. niger conidiospores, D-mannitol is the predominant carbon-containing compound and makes up 10 to 15% of the dry weight (41). The metabolic pathway for mannitol biosynthesis in ascomycete and deuteromycete fungi most likely consists of two steps (19) (Fig. 1). Fructose 6-phosphate is reduced to mannitol 1-phosphate by NAD ϩ -dependent mannitol 1-phosphate dehydrogenase (MPD), followed by the dephosphorylation of mannitol 1-phosphate, which is catalyzed by mannitol 1-phosphate phosphatase (MPP), yielding mannitol. The presence of MPD and MPP in several fungi, such as A. niger (22), Aspergillus nidulans (34), and Alternaria alternata (18), has been demonstrated, but these enzymes are also responsible for mannitol biosynthesis in protozoa...

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Mannitol metabolism in plants: a method for coping with stress

Cited by 335 publications

References 38 publications

Sugar Repression of Mannitol Dehydrogenase Activity in Celery Cells

Sugar Repression of Mannitol Dehydrogenase Activity in Celery Cells

Exogenous application of mannitol and thiourea regulates plant growth and oxidative stress responses in salt-stressed maize (Zea maysL.)

Mannitol Is Required for Stress Tolerance inAspergillus nigerConidiospores

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