Mannitol metabolism in the phytopathogenic fungus Alternaria alternata

Vélëz, Heriberto; Glassbrook, Norman J.; Daub, Margaret E.

doi:10.1016/j.fgb.2006.09.008

Cited by 70 publications

(58 citation statements)

References 35 publications

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“…Further, the discovery that mannitol is secreted by the tobacco pathogen Alternaria alternata in response to host leaf extracts (Jennings et al 1998), together with Voegele et al's (2005) observation that the bean rust Uromyces fabae secretes mannitol into the apoplast during infection, supports the hypothesis that fungal pathogens secrete mannitol to disrupt ROS-mediated plant defenses. This hypothesis is further consistent with the demonstration that mannitol-deWcient mutants of A. alternata created by targeted gene disruption (Vélëz et al 2007) have reduced pathogenicity on tobacco (Vélëz et al 2008). Thus, in addition to mannitol's accepted role in fungal metabolism, mannitol production and secretion appear to be signiWcant pathogenicity factors for A. alternata.…”

Section: Introductionsupporting

confidence: 77%

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Salicylic acid stimulates secretion of the normally symplastic enzyme mannitol dehydrogenase: a possible defense against mannitol-secreting fungal pathogens

Cheng

Zamski

Guo

et al. 2009

Planta

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The sugar alcohol mannitol is an important carbohydrate with well-documented roles in both metabolism and osmoprotection in many plants and fungi. In addition to these traditionally recognized roles, mannitol is reported to be an antioxidant and as such may play a role in host-pathogen interactions. Current research suggests that pathogenic fungi can secrete mannitol into the apoplast to suppress reactive oxygen-mediated host defenses. Immunoelectron microscopy, immunoblot, and biochemical data reported here show that the normally symplastic plant enzyme, mannitol dehydrogenase (MTD), is secreted into the apoplast after treatment with the endogenous inducer of plant defense responses salicylic acid (SA). In contrast, a cytoplasmic marker protein, hexokinase, remained cytoplasmic after SA-treatment. Secreted MTD retained activity after export to the apoplast. Given that MTD converts mannitol to the sugar mannose, MTD secretion may be an important component of plant defense against mannitol-secreting fungal pathogens such as Alternaria. After SA treatment, MTD was not detected in the Golgi apparatus, and its SA-induced secretion was resistant to brefeldin A, an inhibitor of Golgi-mediated protein transport. Together with the absence of a known extracellular targeting sequence on the MTD protein, these data suggest that a plant's response to pathogen challenge may include secretion of selected defensive proteins by as yet uncharacterized, non-Golgi mechanisms.

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Section: Introductionsupporting

confidence: 77%

“…Most fungi, including many pathogenic ones, also make mannitol (Bieleski 1982;Jennings 1984) although by a very diVerent pathway than in plants (Stoop et al 1996;Vélëz et al 2007). In fungi, mannitol has been hypothesized to serve as a metabolic reserve and in NAD(P)H recycling.…”

Section: Introductionmentioning

confidence: 99%

Salicylic acid stimulates secretion of the normally symplastic enzyme mannitol dehydrogenase: a possible defense against mannitol-secreting fungal pathogens

Cheng

Zamski

Guo

et al. 2009

Planta

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“…The activities of MTD and MPD in the cell-free protein extracts were separately assayed at 25°C by monitoring spectrophotometrically the decreases in the concentrations of the cofactors NADPH and NADH at A 340 with a documented method (Vélëz et al 2007). A total volume of 1.0 ml reaction mixture consisted of 100 mM Tris-HCl (pH 7.5), 0.2 mM NADPH, 0.6 M fructose and 100 ll protein extract for the MTD activity or of 100 mM Tris-HCl (pH 7.0), 0.2 mM NADH, 2.5 mM fructose 6-phosphate and 100 ll protein extract for the MPD activity.…”

Section: Assays Of Trehalase Mtd and Mpd Activities In Stressed Cultmentioning

confidence: 99%

“…The present study sought to explore possible roles of trehalose and trehalase in the tolerance of B. bassiana to the thermal stress of summer by examining trehalose accumulation and trehalase activity in stressed and unstressed cells. The content of intracellular D-mannitol, another physiologically important low-molecule solute, was also assayed in parallel with the activities of mannitol 1-phosphate dehydrogenase (MPD) and mannitol dehydrogenase (MTD), which are involved in fungal mannitol metabolism (Ruijter et al 2003;Vélëz et al 2007). …”

Section: Introductionmentioning

confidence: 99%

Physiological implication of intracellular trehalose and mannitol changes in response of entomopathogenic fungus Beauveria bassiana to thermal stress

Liu

Ying

Feng

et al. 2008

Antonie van Leeuwenhoek

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To explore possible role of intracellular trehalose accumulation in fungal tolerance to summer-like thermal stress, 3-day colonies of Beauveria bassiana grown on a glucose-free medium at 25 degrees C were separately exposed to 35, 37.5 and 40 degrees C for 1-18 h, respectively. Trehalose accumulation in stressed mycelia increased from initial 4.2 to 88.3, 74.7 and 65.5 mg g(-1) biomass after 6-h stress at 35, 37.5 and 40 degrees C, respectively, while intracellular mannitol level generally declined with higher temperatures and longer stress time. The stress-enhanced trehalose level was significantly correlated to decreased trehalase activity (r(2) = 0.73) and mannitol content (r(2) = 0.38), which was inversely correlated to the activity of mannitol dehydrogenase (r(2) = 0.41) or mannitol 1-phosphate dehydrogenase (r(2) = 0.30) under the stresses. All stressed cultures were successfully recovered at 25 degrees C but their vigor depended on stressful temperature, time length and the interaction of both (r (2) = 0.98). The highest level of 6-h trehalose accumulation at 35 degrees C was found enhancing the tolerance of the stressed cultures to the greater stress of 48 degrees C. The results suggest that the trehalose accumulation result partially from metabolized mannitol and contribute to the fungal thermotolerance. Trehalase also contributed to the thermotolerance by hydrolyzing accumulated trehalose under the conditions of thermal stress and recovery.

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“…Mannitol-1-phosphate 5-dehydrogenase is proposed as main enzyme for mannitol biosynthesis (Vélëz et al 2007), and the enzyme abundance in the fruiting body of C. sinensis was near 13-fold higher than that in mycelia (Table 1). As a result, it may increase the content of mannitol in natural C. sinensis (Wang et al 2009; Guan et al 2010).…”

Section: Proteins Involved In Carbohydrate Metabolismmentioning

confidence: 99%

Potential molecular mechanisms for fruiting body formation of Cordyceps illustrated in the case ofCordyceps sinensis

et al. 2017

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The fruiting body formation mechanisms of Cordyceps sinensis are still unclear. To explore the mechanisms, proteins potentially related to the fruiting body formation, proteins from fruiting bodies, and mycelia of Cordyceps species were assessed by using two-dimensional fluorescence difference gel electrophoresis, and the differential expression proteins were identified by matrix-assisted laser desorption/ionisation tandem time of flight mass spectrometry. The results showed that 198 differential expression proteins (252 protein spots) were identified during the fruiting body formation of Cordyceps species, and 24 of them involved in fruiting body development in both C. sinensis and other microorganisms. Especially, enolase and malate dehydrogenase were first found to play an important role in fruiting body development in macro-fungus. The results implied that cAMP signal pathway involved in fruiting body development of C. sinensis, meanwhile glycometabolism, protein metabolism, energy metabolism, and cell reconstruction were more active during fruiting body development. It has become evident that fruiting body formation of C. sinensis is a highly complex differentiation process and requires precise integration of a number of fundamental biological processes. Although the fruiting body formation mechanisms for all these activities remain to be further elucidated, the possible mechanism provides insights into the culture of C. sinensis.

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Mannitol metabolism in the phytopathogenic fungus Alternaria alternata

Cited by 70 publications

References 35 publications

Salicylic acid stimulates secretion of the normally symplastic enzyme mannitol dehydrogenase: a possible defense against mannitol-secreting fungal pathogens

Salicylic acid stimulates secretion of the normally symplastic enzyme mannitol dehydrogenase: a possible defense against mannitol-secreting fungal pathogens

Physiological implication of intracellular trehalose and mannitol changes in response of entomopathogenic fungus Beauveria bassiana to thermal stress

Potential molecular mechanisms for fruiting body formation of Cordyceps illustrated in the case ofCordyceps sinensis

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