Starch synthesis and carbohydrate oxidation in amyloplasts from developing wheat endosperm

Planta ◽  
1994 ◽  
Vol 194 (4) ◽  
pp. 454-460 ◽  
Author(s):  
Ian J. Tetlow ◽  
Kerry J. Blissett ◽  
Michael J. Emes
Keyword(s):  
Starch Synthesis ◽  
Carbohydrate Oxidation ◽  
Wheat Endosperm

Metabolite pools during starch synthesis and carbohydrate oxidation in amyloplasts isolated from wheat endosperm

Planta ◽  
1997 ◽  
Vol 204 (1) ◽  
pp. 100-108 ◽  
Author(s):  
Ian J. Tetlow ◽  
Kerry J. Blissett ◽  
Michael J. Emes
Keyword(s):  
Starch Synthesis ◽  
Carbohydrate Oxidation ◽  
Wheat Endosperm

Starch Synthesis and Carbohydrate Oxidation In Developing Potato Tuber Amyloplasts

2000 ◽  
Vol 3 (5) ◽  
pp. 892-895
Author(s):  
Muhammad Naeem . ◽  
Michael J. Emes . ◽  
M. Yasin Ashraf .
Keyword(s):  
Potato Tuber ◽  
Starch Synthesis ◽  
Carbohydrate Oxidation

scholarly journals Pyrophosphate:fructose 6-phosphate 1-phosphotransferase and glycolysis in non-photosynthetic tissues of higher plants

1985 ◽  
Vol 227 (1) ◽  
pp. 299-304 ◽  
Author(s):  
T ap Rees ◽  
J H Green ◽  
P M Wilson
Keyword(s):  
Pisum Sativum ◽  
Beta Vulgaris ◽  
Higher Plants ◽  
Starch Synthesis ◽  
Carbohydrate Oxidation ◽  
Allium Porrum ◽  
Catalytic Activities ◽  
Net Flux ◽  
Arum Maculatum ◽  
Fructose 1,6 Bisphosphate

The activity of pyrophosphate:fructose-6-phosphate 1-phosphotransferase [PFK (PPi); EC 2.7.1.90] in extracts of the storage tissues of leek (Allium porrum), beetroot (Beta vulgaris) and roots of darnel (Lolium temulentum) exceeded 0.15 mumol/min per g fresh wt. As net flux from fructose 1,6-bisphosphate to fructose 6-phosphate in these tissues is unlikely, it is suggested that PFK (PPi) does not contribute to gluconeogenesis or starch synthesis. The maximum catalytic activities of PFK (PPi) in apex, stele and cortex of the root of pea (Pisum sativum) and in the developing and the thermogenic club of the spadix of cuckoo-pint (Arum maculatum) were measured and compared with those of phosphofructokinase, and to estimates of the rates of carbohydrate oxidation. PPi and fructose 2,6-bisphosphate in Arum clubs were measured. The above measurements are consistent with a glycolytic role for PFK (PPi) in tissues where there is marked biosynthesis, but not in the thermogenic club of Arum. The possibility that PFK (PPi) is a means of synthesizing pyrophosphate is discussed.

The NAC transcription factor NAC019-A1 is a negative regulator of starch synthesis in wheat developing endosperm

2020 ◽  
Vol 71 (19) ◽  
pp. 5794-5807
Author(s):  
Yunchuan Liu ◽  
Jian Hou ◽  
Xiaolu Wang ◽  
Tian Li ◽  
Uzma Majeed ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Oryza Sativa L ◽  
Starch Content ◽  
Wheat Yield ◽  
Starch Synthesis ◽  
Kernel Weight ◽  
Nac Transcription Factor ◽  
Negative Regulator ◽  
Starch Granules ◽  
Wheat Endosperm

Abstract Starch is a major component of wheat (Triticum aestivum L.) endosperm and is an important part of the human diet. The functions of many starch synthesis genes have been elucidated. However, little is known about their regulatory mechanisms in wheat. Here, we identified a novel NAC transcription factor, TaNAC019-A1 (TraesCS3A02G077900), that negatively regulates starch synthesis in wheat and rice (Oryza sativa L.) endosperms. TaNAC019-A1 was highly expressed in the endosperm of developing grains and encoded a nucleus-localized transcriptional repressor. Overexpression of TaNAC019-A1 in rice and wheat led to significantly reduced starch content, kernel weight, and kernel width. The TaNAC019-A1-overexpression wheat lines had smaller A-type starch granules and fewer B-type starch granules than wild-type. Moreover, TaNAC019-A1 could directly bind to the ‘ACGCAG’ motif in the promoter regions of ADP-glucose pyrophosphorylase small subunit 1 (TaAGPS1-A1, TraesCS7A02G287400) and TaAGPS1-B1 (TraesCS7B02G183300) and repress their expression, thereby inhibiting starch synthesis in wheat endosperm. One haplotype of TaNAC019-B1 (TaNAC019-B1-Hap2, TraesCS3B02G092800) was positively associated with thousand-kernel weight and underwent positive selection during the Chinese wheat breeding process. Our data demonstrate that TaNAC019-A1 is a negative regulator of starch synthesis in wheat endosperm and provide novel insight into wheat yield improvement.

Comprehensive analysis of the transcription of starch synthesis genes and the transcription factor RSR1 in wheat (Triticum aestivum) endosperm

Genome ◽  
2013 ◽  
Vol 56 (2) ◽  
pp. 115-122 ◽  
Author(s):  
Guo-Zhang Kang ◽  
Wei Xu ◽  
Guo-Qin Liu ◽  
Xiao-Qi Peng ◽  
Tian-Cai Guo
Keyword(s):  
Triticum Aestivum ◽  
Transcription Factor ◽  
Expression Profiles ◽  
Expression Patterns ◽  
Starch Synthesis ◽  
Grain Development ◽  
Wheat Endosperm ◽  
Group 2 ◽  
Endosperm Starch ◽  
Late Stages

The cDNA sequences of 26 starch synthesis genes were identified in common wheat (Triticum aestivum L.), and their transcript levels were measured using quantitative real-time RT–PCR to assess the function of individual genes and the regulatory mechanism in wheat endosperm. The expression patterns of 26 genes in wheat endosperm were classified into three groups. The genes in group 1 were richly expressed in the early stage of grain development and may be involved in the construction of fundamental cell machinery, synthesis of glucan primers, and initiation of starch granules. The genes in group 2 were highly expressed during the middle and late stages of grain development, and their expression profiles were similar to the accumulation rate of endosperm starch; these genes are presumed to play a crucial role in starch production. The genes in group 3 were scantily expressed throughout the grain development period and might be associated with transitory starch synthesis. Transcripts of the negative transcription factor TaRSR1 were high at the early and late stages of grain development but low during the middle stage. The expression pattern of TaRSR1 was almost opposite to those of the group 2 starch synthesis genes, indicating that TaRSR1 might negatively regulate the expression of many endosperm starch synthesis genes during grain development.

scholarly journals Starch accumulation, activities of key enzyme and gene expression in starch synthesis of wheat endosperm with different starch contents

2011 ◽  
Vol 51 (3) ◽  
pp. 419-429 ◽  
Author(s):  
Zibu Wang ◽  
Weihua Li ◽  
Juncang Qi ◽  
Peichun Shi ◽  
Yongan Yin
Keyword(s):  
Gene Expression ◽  
Starch Synthesis ◽  
Starch Accumulation ◽  
Wheat Endosperm ◽  
Key Enzyme

scholarly journals Introduction of glucan synthase into the cytosol in wheat endosperm causes massive maltose accumulation and represses starch synthesis

2021 ◽  
Author(s):  
Tina B. Schreier ◽  
Brendan Fahy ◽  
Laure C. David ◽  
Hamad Siddiqui ◽  
Roger Castells‐Graells ◽  
...  
Keyword(s):  
Starch Synthesis ◽  
Glucan Synthase ◽  
Wheat Endosperm

Effects of Temperature on the Conversion of Sucrose to Starch in the Developing Wheat Endosperm

1986 ◽  
Vol 13 (5) ◽  
pp. 605 ◽  
Author(s):  
SS Bhullar ◽  
CF Jenner
Keyword(s):  
Elevated Temperature ◽  
Starch Synthesis ◽  
Grain Filling ◽  
Residual Effects ◽  
Effect Of Temperature ◽  
Soluble Carbohydrate ◽  
Wheat Endosperm ◽  
14Co2 Production ◽  
Response To Temperature

Elevated temperature during grain filling resulted in reduced single grain weight due largely to an effect of temperature on the accumulation of starch in the endosperm. Wheat endosperm was cultured in vitro on solutions of [14C]sucrose and the responses to variation in temperature within the range 15-35°C were evaluated in terms of the absorption of radioactive sugar, the evolution of 14CO2, and the incorporation of radioactivity into starch. At 35°C the level of 14C in the intracellular pool of soluble carbohydrate was higher than it was at 30°C, and the average Q,10 for 14CO2 production was 2.1. Incorporation of 14C into starch was greater at 30°C than at 25°C, but at 35°C only half as much [14C]starch was produced compared with that at 30°C. Residual effects of exposure of ears to brief episodes of elevated temperature were investigated by culturing endosperm isolated from such ears on [14C]sucrose at a standard temperature (25°C). Two days of exposure resulted in greater amounts of [14C]starch produced, due to accelerated starch depo- sition, but longer periods (4-6 days) at elevated temperature resulted in substantial reductions in [14C]starch deposition. Exposure to elevated temperature also hastened the onset of chlorophyll degradation in the pericarp of the grain. Two types of response to temperature appear to be involved: a comparatively low temperature optimum for starch synthesis, and an irreversible reduction in the capacity of the endosperm to convert sucrose to starch resulting from exposure of the ears, or the grains themselves, to elevated temperature.

Starch synthesis by isolated amyloplasts from wheat endosperm

Planta ◽  
1988 ◽  
Vol 175 (1) ◽  
pp. 33-38 ◽  
Author(s):  
R. H. Tyson ◽  
T. ap Rees
Keyword(s):  
Starch Synthesis ◽  
Wheat Endosperm

scholarly journals Enzymic capacities of amyloplasts from wheat (Triticum aestivum) endosperm

1988 ◽  
Vol 255 (2) ◽  
pp. 391-396 ◽  
Author(s):  
G Entwistle ◽  
T A Rees
Keyword(s):  
Triticum Aestivum ◽  
Significant Proportion ◽  
Starch Synthesis ◽  
Immunoblot Analysis ◽  
Glycolytic Enzyme ◽  
Starch Synthase ◽  
Wheat Endosperm ◽  
Fructose 1,6 Bisphosphatase ◽  
Enzyme Distribution ◽  
Adp Glucose Pyrophosphorylase

Lysates of protoplasts from the endosperm of developing grains of wheat (Triticum aestivum) were fractionated on density gradients of Nycodenz to give amyloplasts. Enzyme distribution on the gradients suggested that: (i) starch synthase and ADP-glucose pyrophosphorylase are confined to the amyloplasts; (ii) pyrophosphate: fructose-6-phosphate 1-phosphotransferase and UDP-glucose pyrophosphorylase are confined to the cytosol; (iii) a significant proportion (23-45%) of each glycolytic enzyme, from phosphoglucomutase to pyruvate kinase inclusive, is in the amyloplast. Starch synthase, ADP-glucose pyrophosphorylase and each of the glycolytic enzymes showed appreciable latency when assayed in unfractionated lysates of protoplasts. No activity of fructose-1,6-bisphosphatase was found in amyloplasts or in homogenates of endosperm. Antibody to plastidic fructose-1,6-bisphosphatase did not react positively, in an immunoblot analysis, with any protein in extracts of wheat endosperm. It is argued that wheat endosperm lacks significant plastidic fructose-1,6-bisphosphatase and that carbon for starch synthesis does not enter the amyloplast as a C-3 compound but probably as hexose phosphate.

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