Redox Regulation of Starch Metabolism

Skryhan, Katsiaryna; Gurrieri, Libero; Sparla, Francesca; Trost, Paolo Bernardo; Blennow, Andreas

doi:10.3389/fpls.2018.01344

Cited by 59 publications

(57 citation statements)

References 74 publications

(122 reference statements)

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“…Meanwhile, NTRC forms a complete Trx system in a single polypeptide that relies on NADPH and, thus, might also be operative during the night. Trxs and NTRC are both reported to control multiple plant processes, including the biosynthesis of starch [24,54]. Previous studies led to the view that these two systems may have non-overlapping functions in plants [55].…”

Section: Discussionmentioning

confidence: 99%

“…The activities of two well-known redox regulated enzymes, SS and AGPase [24], were analyzed in order to investigate whether o/exNTRC and o/exTrxf plants show higher starch synthesis capacity. Interestingly, o/exTrxf plants displayed a clear increase on SS activity, while the o/exNTRC plants showed no differences when compared to Wt plants (Figure 5a).…”

Section: Comparative Analysis Of Enzymes Related To Starch Synthesismentioning

confidence: 99%

“…In recent years, additional candidates have been added to the list of reductively activated starch metabolizing enzymes, some of which are related to starch degradation [24,36]. Besides the Fd/Trx system, which is presumed to upregulate starch degradation during stress conditions or in guard cells under light conditions [39,46], NTRC could also provide reductive regulation of these enzymes in the night.…”

Section: Enhanced Starch Content In O/exntrc Leaves As a Consequence mentioning

confidence: 99%

“…Starch metabolism is extraordinarily well tuned due to the presence of very sophisticated regulatory mechanisms. Post-translational modifications, including redox regulation, are the main way by which the activity of enzymes that are involved in transient starch metabolism are regulated [24,25]. In higher plants, AGPase was described as a heterotetramer consisting of two large (AGPS) and two small (AGPB) subunits.…”

Section: Introductionmentioning

confidence: 99%

“…In addition to starch synthesis, enzymes that are involved in starch degradation have been shown to be under redox control [24,36]. Among them, chloroplast localized AMY3 could be activated by reduced Trxs in Arabidopsis, with Trx f being the most effective [38].…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

NTRC and Thioredoxin f Overexpression Differentially Induces Starch Accumulation in Tobacco Leaves

Ancín¹,

Larraya²,

Millán³

et al. 2019

Plants

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Thioredoxin (Trx) f and NADPH-dependent Trx reductase C (NTRC) have both been proposed as major redox regulators of starch metabolism in chloroplasts. However, little is known regarding the specific role of each protein in this complex mechanism. To shed light on this point, tobacco plants that were genetically engineered to overexpress the NTRC protein from the chloroplast genome were obtained and compared to previously generated Trx f-overexpressing transplastomic plants. Likewise, we investigated the impact of NTRC and Trx f deficiency on starch metabolism by generating Nicotiana benthamiana plants that were silenced for each gene. Our results demonstrated that NTRC overexpression induced enhanced starch accumulation in tobacco leaves, as occurred with Trx f. However, only Trx f silencing leads to a significant decrease in the leaf starch content. Quantitative analysis of enzyme activities related to starch synthesis and degradation were determined in all of the genotypes. Zymographic analyses were additionally performed to compare the amylolytic enzyme profiles of both transplastomic tobacco plants. Our findings indicated that NTRC overexpression promotes the accumulation of transitory leaf starch as a consequence of a diminished starch turnover during the dark period, which seems to be related to a significant reductive activation of ADP-glucose pyrophosphorylase and/or a deactivation of a putative debranching enzyme. On the other hand, increased starch content in Trx f-overexpressing plants was connected to an increase in the capacity of soluble starch synthases during the light period. Taken together, these results suggest that NTRC and the ferredoxin/Trx system play distinct roles in starch turnover.

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Section: Discussionmentioning

confidence: 99%

Section: Comparative Analysis Of Enzymes Related To Starch Synthesismentioning

confidence: 99%

Section: Enhanced Starch Content In O/exntrc Leaves As a Consequence mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

NTRC and Thioredoxin f Overexpression Differentially Induces Starch Accumulation in Tobacco Leaves

Ancín¹,

Larraya²,

Millán³

et al. 2019

Plants

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The activation of Chlamydomonas reinhardtii alpha amylase 2 by glutamine requires its N‐terminal aspartate kinase–chorismate mutase–tyrA (ACT) domain

Scholtysek,

Poetsch,

Hofmann

et al. 2024

Plant Direct

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The coordination of assimilation pathways for all the elements that make up cellular components is a vital task for every organism. Integrating the assimilation and use of carbon (C) and nitrogen (N) is of particular importance because of the high cellular abundance of these elements. Starch is one of the most important storage polymers of photosynthetic organisms, and a complex regulatory network ensures that biosynthesis and degradation of starch are coordinated with photosynthetic activity and growth. Here, we analyzed three starch metabolism enzymes of Chlamydomonas reinhardtii that we captured by a cyclic guanosine monophosphate (cGMP) affinity chromatography approach, namely, soluble starch synthase STA3, starch‐branching enzyme SBE1, and α‐amylase AMA2. While none of the recombinant enzymes was directly affected by the presence of cGMP or other nucleotides, suggesting an indirect binding to cGMP, AMA2 activity was stimulated in the presence of L‐glutamine (Gln). This activating effect required the enzyme's N‐terminal aspartate kinase–chorismate mutase–tyrA domain. Gln is the first N assimilation product and not only a central compound for the biosynthesis of N‐containing molecules but also a recognized signaling molecule for the N status. Our observation suggests that AMA2 might be a means to coordinate N and C metabolism at the enzymatic level, increasing the liberation of C skeletons from starch when high Gln levels signal an abundance of assimilated N.

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The Effect and Regulation Mechanism of Powdery Mildew on Wheat Grain Carbon Metabolism

et al. 2022

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The effects of powdery mildew on gene expressions and activities of carbon (C) metabolism enzymes in Zhengmai 103 (resistant) and Xi'nong 979 (susceptible) are studied. Under severe powdery mildew, expressions and activities of sucrose synthase, uridine‐diphosphate glucose pyrophosphorylase, glyceraldehyde‐3‐phosphate dehydrogenase (GAPDH), and cytosolic α‐1,4‐glucan phosphorylase decrease at 20 or 25–30 days after anthesis, and total soluble sugars content also decreases. It indicates that the first part of C metabolism (sucrose degradation) changes and total C flux reduces. Meanwhile, decreases in expressions and activities of adenosine‐diphosphate glucose pyrophosphorylase (AGPase), soluble starch synthase (SSS), starch‐branching enzyme I and II (SBEI and SBEII), and plastidic α‐1,4‐glucan phosphorylase coincide with decreases in amylopectin content, whereas increases in granule‐bound starch synthase I (GBSSI) expression and activity coincide with increases in amylose content. It shows that the second part of C metabolism (starch synthesis) changes. Therefore, powdery mildew alters C metabolism. In addition, it also induces defense responses in grains, such as the up‐regulation of a defense‐related protein endogenous α‐amylase/subtilisin inhibitor. Since GAPDH, AGPase, SSS, SBEII, and GBSSI are regulated by redox, changes of C metabolism are mainly regulated by cellular redox status.

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Redox Regulation of Starch Metabolism

Cited by 59 publications

References 74 publications

NTRC and Thioredoxin f Overexpression Differentially Induces Starch Accumulation in Tobacco Leaves

NTRC and Thioredoxin f Overexpression Differentially Induces Starch Accumulation in Tobacco Leaves

The activation of Chlamydomonas reinhardtii alpha amylase 2 by glutamine requires its N‐terminal aspartate kinase–chorismate mutase–tyrA (ACT) domain

The Effect and Regulation Mechanism of Powdery Mildew on Wheat Grain Carbon Metabolism

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