Regulation of Trehalose Metabolism and Its Relevance to cell Growth and Function

Thevelein, Johan M.

doi:10.1007/978-3-662-10367-8_19

Cited by 59 publications

(64 citation statements)

References 160 publications

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“…On the other hand, disruption of TPS activity in M. grisea resulted in the inhibition of growth on several carbon sources, similar to what has been described for yeast (Thevelein & Hohmann, 1995). This growth disturbance of TPS-deficient mutants has been explained by the deregulation of glycolytic flux due to the absence of T6P (Gancedo & Flores, 2004;Eastmond & Graham, 2003;Thevelein, 1996). A similar explanation for the impaired germination of the Dtps1 mutant in the presence of fructose or glucose was supported by the observation of a high sensitivity of B. cinerea hexokinase to T6P.…”

Section: Discussionsupporting

confidence: 67%

“…The protective properties of trehalose during heat, dehydration and oxidative stresses are explained by its ability to stabilize the native conformation of proteins and membranes, but the molecular basis for this is not well understood (Singer & Lindquist, 1998). Contradictory models have been proposed to explain the stabilizing effects of trehalose, either by replacement of water molecules from the surface of biomolecules, or by entrapment of residual water molecules close to the biomolecule (Thevelein, 1996;Pereira et al, 2004;Skibinsky et al, 2005).…”

Section: Introductionmentioning

confidence: 99%

“…Trehalose breakdown is catalysed by trehalases. Originally, two types of trehalases were described in fungi: so-called acid trehalases, with a low pH optimum, which are required for utilization of trehalose as a carbon source, and neutral trehalases, which mobilize intracellular trehalose (Thevelein, 1996;Amaral et al, 1997). Magnaporthe grisea, which does not possess an acid trehalase, contains a neutral trehalase (NTH1), and a new type of fungal trehalase (TRE1) that has properties of both neutral and acid trehalases (Foster et al, 2003).…”

Section: Introductionmentioning

confidence: 99%

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Trehalose metabolism is important for heat stress tolerance and spore germination of Botrytis cinerea

2006

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To analyse the role of trehalose as stress protectant and carbon storage compound in the grey mould fungus Botrytis cinerea, mutants defective in trehalose-6-phosphate synthase (TPS1) and neutral trehalase (TRE1) were constructed. The Dtps1 mutant was unable to synthesize trehalose, whereas the Dtre1 mutant showed elevated trehalose levels compared to the wild-type and was unable to mobilize trehalose during conidial germination. Both mutants showed normal vegetative growth and were not affected in plant pathogenicity. Growth of the Dtps1 mutant was more heat sensitive compared to the wild-type. Similarly, Dtps1 conidia showed a shorter survival under heat stress, and their viability at moderate temperatures was strongly reduced. In germinating wild-type conidia, rapid trehalose degradation occurred only when germination was induced in the presence of nutrients. In contrast, little trehalose breakdown was observed during germination on hydrophobic surfaces in water. Here, addition of cAMP to conidia induced trehalose mobilization and accelerated the germination process, probably by activation of TRE1. In accordance with these data, both mutants showed germination defects only in the presence of sugars but not on hydrophobic surfaces in the absence of nutrients. The data indicate that in B. cinerea trehalose serves as a stress protectant, and also as a significant but not essential carbon source for germination when external nutrients are low. In addition, evidence was obtained that trehalose 6-phosphate plays a role as a regulator of glycolysis during germination.

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Section: Discussionsupporting

confidence: 67%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Trehalose metabolism is important for heat stress tolerance and spore germination of Botrytis cinerea

2006

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“…The universal mobilization of trehalose during growth resumption from resting stages supports a role as a storage carbohydrate (Arguelles, 2000 ;Thevelein, 1984Thevelein, , 1996. However, because of a number of physico-chemical properties, including high hydrophilicity and chemical stability, non-hygroscopic glass formation and the absence of internal hydrogen bond formation, trehalose is apparently able to serve a unique role as stress metabolite (Arguelles, 2000 ;Thevelein, 1996).…”

Section: Abbreviationsmentioning

confidence: 98%

Trehalose is required for the acquisition of tolerance to a variety of stresses in the filamentous fungus Aspergillus nidulans The GenBank accession number for the sequence reported in this paper is AF043230.

et al. 2001

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Trehalose is a non-reducing disaccharide found at high concentrations in Aspergillus nidulans conidia and rapidly degraded upon induction of conidial germination. Furthermore, trehalose is accumulated in response to a heat shock or to an oxidative shock. The authors have characterized the A. nidulans tpsA gene encoding trehalose-6-phosphate synthase, which catalyses the first step in trehalose biosynthesis. Expression of tpsA in a Saccharomyces cerevisiae tps1 mutant revealed that the tpsA gene product is a functional equivalent of the yeast Tps1 trehalose-6-phosphate synthase. The A. nidulans tpsA-null mutant does not produce trehalose during conidiation or in response to various stress conditions. While germlings of the tpsA mutant show an increased sensitivity to moderate stress conditions (growth at 45 SC or in the presence of 2 mM H 2 O 2 ), they display a response to severe stress (60 min at 50 SC or in the presence of 100 mM H 2 O 2 ) similar to that of wild-type germlings. Furthermore, conidia of the tpsA mutant show a rapid loss of viability upon storage. These results are consistent with a role of trehalose in the acquisition of stress tolerance. Inactivation of the tpsA gene also results in increased steady-state levels of sugar phosphates but does not prevent growth on rapidly metabolizable carbon sources (glucose, fructose) as seen in Saccharomyces cerevisiae. This suggests that trehalose 6-phosphate is a physiological inhibitor of hexokinase but that this control is not essential for proper glycolytic flux in A. nidulans. Interestingly, tpsA transcription is not induced in response to heat shock or during conidiation, indicating that trehalose accumulation is probably due to a post-translational activation process of the trehalose 6-phosphate synthase.

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“…Such high trehalose levels have been reported for strains having mutations that directly or indirectly lead to low activity of cAPK [17,51]. After shift down from the heat-stress temperature of 40°C to the normal growth temperature of 30°C, the very high trehalose level accumulated in the tpk1tpk2TPK3 mutant decreased strongly.…”

Section: Discussionmentioning

confidence: 56%

Stability of neutral trehalase during heat stress in Saccharomyces cerevisiae is dependent on the activity of the catalytic subunits of cAMP‐dependent protein kinase, Tpk1 and Tpk2

Zähringer

Holzer

Nwaka

1998

European Journal of Biochemistry

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In Saccharomyces cerevisiae cAMP-dependent protein kinase (cAPK) is involved in nutrient sensing and growth regulation via the Ras/cAMP pathway. Target enzymes, e.g. neutral trehalase, are activated or inactivated rapidly by cAPK-mediated phosphorylation. In addition, stress-induced transcription of genes of the general stress-response, e.g. HSP12, is negatively regulated via cAPK.We have investigated the effect of low cAPK activity on the stress-induced expression of neutral trehalase Nth1p. For this purpose we used mutants (tpk1tpk2TPK3, tpk1TPK2tpk3 and TPK1tpk2tpk3) with double knockouts of the three TPK genes encoding catalytic subunits of cAPK. It is shown that the tpk1tpk2TPK3 mutant, which has very low cAPK activity, exhibits a heat-stress-induced inactivation of neutral trehalase that is not observed in tpk1TPK2tpk3, TPK11tpk2tpk3 mutants and wild-type cells. However, heat stress induces an increase in NTH1 mRNA in the tpk1tpk2TPK3 mutant. Introduction of a plasmid carrying the TPK1 or TPK2 gene into tpk1tpk2TPK3 cells restores the heat-induced increase of neutral trehalase activity. In vitro and in vivo results suggest that the heat induced inactivation of neutral trehalase is due to a reversible inactivation of Nth1p. Our data indicate that a certain level of phosphorylation is essential for maintenance of neutral trehalase activity during heat shock in S. cerevisiae. Two identical putative cAPK phosphorylation sites have been found in the sequence predicted for the Nth1p. Stabilization and activation of neutral trehalase may be regulated by these sites. Furthermore, our data suggest that the heat-stress-induced transcription of the NTH1 gene is not negatively regulated by cAPK, that the TPK genes have no effect on the glucose repression of the NTH1 gene, and that non-detectable neutral trehalase activity in derepressed tpk1tpk2TPK3 cells is correlated with the reduced thermotolerance observed in this strain, similar to the heat-shock-recovery defect reported for the nth1∆ mutant.

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Regulation of Trehalose Metabolism and Its Relevance to cell Growth and Function

Cited by 59 publications

References 160 publications

Trehalose metabolism is important for heat stress tolerance and spore germination of Botrytis cinerea

Trehalose metabolism is important for heat stress tolerance and spore germination of Botrytis cinerea

Trehalose is required for the acquisition of tolerance to a variety of stresses in the filamentous fungus Aspergillus nidulans The GenBank accession number for the sequence reported in this paper is AF043230.

Stability of neutral trehalase during heat stress in Saccharomyces cerevisiae is dependent on the activity of the catalytic subunits of cAMP‐dependent protein kinase, Tpk1 and Tpk2

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