Characterization of starch phosphorylases in barley grains

Higgins, Jody; Kosar-Hashemi, Behjat; Li, Zhongyi; Howitt, Crispin A.; Larroque, Oscar; Flanagan, Bernadine M.; Morell, Matthew K.; Rahman, Sadequr

doi:10.1002/jsfa.6019

Cited by 22 publications

(11 citation statements)

References 48 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The precise role for SP in starch biosynthesis is not at all clear. SP is present in all tissues synthesizing starch, and its expression in developing endosperm tissue of a number of cereals is closely correlated with periods of active starch accumulation [299,353,354]. Genetic studies in rice indicate a role for SP in starch accumulation.…”

Section: Starch Phosphorylasementioning

confidence: 99%

“…Genetic studies in rice indicate a role for SP in starch accumulation. Rice mutants lacking Pho1 show shrunken endosperm and altered starch granule characteristics when plants were grown at low temperature, possibly indicating a role for SP in starch accumulation under different environmental conditions [355], although a down-regulation of Pho1 expression in barley had no major effects on starch biosynthesis [354]. In addition, studies of SP from other plant tissues show no compelling evidence for a role in transitory starch turnover [356,357].…”

Section: Starch Phosphorylasementioning

confidence: 99%

See 1 more Smart Citation

Starch Biosynthesis in the Developing Endosperms of Grasses and Cereals

Tetlow

Emes

2017

Agronomy

View full text Add to dashboard Cite

Abstract:The starch-rich endosperms of the Poaceae, which includes wild grasses and their domesticated descendents the cereals, have provided humankind and their livestock with the bulk of their daily calories since the dawn of civilization up to the present day. There are currently unprecedented pressures on global food supplies, largely resulting from population growth, loss of agricultural land that is linked to increased urbanization, and climate change. Since cereal yields essentially underpin world food and feed supply, it is critical that we understand the biological factors contributing to crop yields. In particular, it is important to understand the biochemical pathway that is involved in starch biosynthesis, since this pathway is the major yield determinant in the seeds of six out of the top seven crops grown worldwide. This review outlines the critical stages of growth and development of the endosperm tissue in the Poaceae, including discussion of carbon provision to the growing sink tissue. The main body of the review presents a current view of our understanding of storage starch biosynthesis, which occurs inside the amyloplasts of developing endosperms.

show abstract

Section: Starch Phosphorylasementioning

confidence: 99%

Section: Starch Phosphorylasementioning

confidence: 99%

Starch Biosynthesis in the Developing Endosperms of Grasses and Cereals

Tetlow

Emes

2017

Agronomy

View full text Add to dashboard Cite

show abstract

“…Several classes of enzymes are involved in starch biosynthesis, including ADP-glucose pyro-phosphorylase (AGPase), granule-bound starch synthase (GBSS), soluble starch synthase (SSS), starch branching enzyme (SBE), starch debranching enzyme(DBE), and plastidial starch phosphorylase (Pho1), moreover GBSS, SSS, SBE and DBE have multiple isoforms [4, 8–12]. SBE (EC 2.4.1.18), which is a glucosyl transferase that catalyzes the formation of the α-1, 6-linkages of amylopectin, introduces branches in starch chains and thus plays a vital role in amylopectin synthesis.…”

Section: Introductionmentioning

confidence: 99%

Identification and expression analysis of starch branching enzymes involved in starch synthesis during the development of chestnut (Castanea mollissima Blume) cotyledons

Chen

Wang

et al. 2017

PLoS ONE

View full text Add to dashboard Cite

Chinese chestnut (Castanea mollissima Blume) is native to China and distributes widely in arid and semi-arid mountain area with barren soil. As a perennial crop, chestnut is an alternative food source and acts as an important commercial nut tree in China. Starch is the major metabolite in nuts, accounting for 46 ~ 64% of the chestnut dry weight. The accumulation of total starch and amylopectin showed a similar increasing trend during the development of nut. Amylopectin contributed up to 76% of the total starch content at 80 days after pollination (DAP). The increase of total starch mainly results from amylopectin synthesis. Among genes associated with starch biosynthesis, CmSBEs (starch branching enzyme) showed significant increase during nut development. Two starch branching enzyme isoforms, CmSBE I and CmSBE II, were identified from chestnut cotyledon using zymogram analysis. CmSBE I and CmSBE II showed similar patterns of expression during nut development. The accumulations of CmSBE transcripts and proteins in developing cotyledons were characterized. The expressions of two CmSBE genes increased from 64 DAP and reached the highest levels at 77 DAP, and SBE activity reached its peak at 74 DAP. These results suggested that the CmSBE enzymes mainly contributed to amylopectin synthesis and influenced the amylopectin content in the developing cotyledon, which would be beneficial to chestnut germplasm selection and breeding.

show abstract

“…Recently however, it was shown that a reduction of Hv Pho1 protein levels in barley grains to under 30% of their normal value did not lead to any visible starch phenotype [52]. Nevertheless, less than 30% Hv Pho1 activity may be sufficient to drive production of primer molecules acting as initiator-glucans.…”

Section: Discussionmentioning

confidence: 99%

Functional and structural characterization of plastidic starch phosphorylase during barley endosperm development

et al. 2017

View full text Add to dashboard Cite

The production of starch is essential for human nutrition and represents a major metabolic flux in the biosphere. The biosynthesis of starch in storage organs like barley endosperm operates via two main pathways using different substrates: starch synthases use ADP-glucose to produce amylose and amylopectin, the two major components of starch, whereas starch phosphorylase (Pho1) uses glucose-1-phosphate (G1P), a precursor for ADP-glucose production, to produce α-1,4 glucans. The significance of the Pho1 pathway in starch biosynthesis has remained unclear. To elucidate the importance of barley Pho1 (HvPho1) for starch biosynthesis in barley endosperm, we analyzed HvPho1 protein production and enzyme activity levels throughout barley endosperm development and characterized structure-function relationships of HvPho1. The molecular mechanisms underlying the initiation of starch granule biosynthesis, that is, the enzymes and substrates involved in the initial transition from simple sugars to polysaccharides, remain unclear. We found that HvPho1 is present as an active protein at the onset of barley endosperm development. Notably, purified recombinant protein can catalyze the de novo production of α-1,4-glucans using HvPho1 from G1P as the sole substrate. The structural properties of HvPho1 provide insights into the low affinity of HvPho1 for large polysaccharides like starch or amylopectin. Our results suggest that HvPho1 may play a role during the initiation of starch biosynthesis in barley.

show abstract

Characterization of starch phosphorylases in barley grains

Abstract: Two starch phosphorylase activities were identified and characterized in barley grains, and shown to be present during starch synthesis. However, their role in starch synthesis still remains to be elucidated.

Cited by 22 publications

References 48 publications

Starch Biosynthesis in the Developing Endosperms of Grasses and Cereals

Starch Biosynthesis in the Developing Endosperms of Grasses and Cereals

Identification and expression analysis of starch branching enzymes involved in starch synthesis during the development of chestnut (Castanea mollissima Blume) cotyledons

Functional and structural characterization of plastidic starch phosphorylase during barley endosperm development

Contact Info

Product

Resources

About