scholarly journals Silencing GhAGPL1 Reduces the Quality and Quantity of Corms and Cormels in Gladiolus

2017 ◽  
Vol 142 (2) ◽  
pp. 119-125 ◽  
Author(s):  
Shanshan Seng ◽  
Jian Wu ◽  
Jiahui Liang ◽  
Fengqin Zhang ◽  
Qiuyan Yang ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Abscisic Acid ◽  
Starch Content ◽  
Large Subunit ◽  
Starch Synthesis ◽  
Transcript Level ◽  
Starch Accumulation ◽  
Sucrose Content ◽  
Gladiolus Hybridus ◽  
Rate Limiting

Starch accumulation is important during com development. ADP-glucose pyrophosphorylase (AGPase) is the rate-limiting enzyme in starch synthesis. AGPL is the large subunit of AGPase. Here, we isolated and characterized the large subunit of AGPase gene GhAGPL1 in gladiolus (Gladiolus hybridus). GhAGPL1 was highly expressed in sink organs (cormels and corms). The expression of GhAGPL1 was induced by glucose, sucrose, and mannitol, and it was repressed by abscisic acid (ABA). Overexpression of GhAGPL1 in the arabidopsis (Arabidopsis thaliana) apl1 mutant resulted in complementation of AGPase activity and thus starch synthesis. Silencing GhAGPL1 in gladiolus decreased the transcript level of GhAGPL1 and GhSus, and resulted in the reduction of AGPase activity and starch content in gladiolus corm and cormel. Meanwhile, sucrose content was higher in GhAGPL1-silenced corm. Surprisingly, silencing GhAGPL1 in gladiolus produced smaller corms and fewer number of cormels. Overall, GhAGPL1 contributed to the quality and quantity of gladiolus corms and cormels.

scholarly journals Antagonism between abscisic acid and gibberellin regulates starch synthesis and corm development in Gladiolus hybridus

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Jingru Li ◽  
Shanshan Seng ◽  
Donglei Li ◽  
Fengqin Zhang ◽  
Yixuan Liu ◽  
...  
Keyword(s):  
Abscisic Acid ◽  
Starch Synthesis ◽  
Transcript Level ◽  
Hormone Treatment ◽  
Starch Accumulation ◽  
Cut Flowers ◽  
Gladiolus Hybridus ◽  
Hormone Biosynthesis ◽  
Essential Enzyme

AbstractUnderstanding corm development in flower bulbs is of importance for securing the quality of cut flowers and propagation of commercial stocks. Gladiolus is one of the most popular bulb plants worldwide. Its corm development is characterized by starch accumulation. Previous research has shown that phytohormones (especially gibberellin (GA)) are involved in tuber development. However, the relationship between abscisic acid (ABA)/GA and starch during corm development remains unclear. To gain deeper insights into the biological process of corm development, we performed a detailed anatomical characterization of different stages of corm development and analyzed phytohormone levels. Our study showed that corm development is linked to hormones (ABA and GA) and carbohydrates (sucrose and starch). Exogenous hormone treatment and silencing of endogenous hormone biosynthesis genes indicated that ABA positively regulates corm development, while GA acts as an antagonist of ABA function. A sucrose synthase gene (GhSUS2) was shown to be involved in the antagonism between ABA and GA. GhSUS2 was upregulated by ABA and downregulated by GA. The increase in the transcript level of GhSUS2 coincided with the development of corm/cormels. Silencing of GhSUS2 repressed corm development and starch accumulation. In conclusion, we propose that GhSUS2, an essential enzyme in sucrose degradation, is differentially regulated by ABA and GA and controls corm development in Gladiolus.

Suppression of starch synthesis in rice stems splays tiller angle due to gravitropic insensitivity but does not affect yield

2015 ◽  
Vol 42 (1) ◽  
pp. 31 ◽  
Author(s):  
Masaki Okamura ◽  
Tatsuro Hirose ◽  
Yoichi Hashida ◽  
Ryu Ohsugi ◽  
Naohiro Aoki
Keyword(s):  
Double Mutant ◽  
Oryza Sativa L ◽  
Starch Content ◽  
Large Subunit ◽  
Starch Synthesis ◽  
Starch Accumulation ◽  
Gravitropic Response ◽  
Rice Mutant ◽  
Matter Production ◽  
Tiller Angle

In rice (Oryza sativa L.), tiller angle – defined as the angle between the main culm and its side tillers – is one of the important factors involved in light use efficiency. To clarify the relationship between tiller angle, gravitropism and stem-starch accumulation, we investigated the shoot gravitropic response of a low stem-starch rice mutant which lacks a large subunit of ADP-glucose pyrophosphorylase (AGP), called OsAGPL1 and exhibits relatively spread tiller angle. The insensitive gravitropic response exhibited by the mutant led us to the conclusion that insensitivity of gravitropism caused by stem-starch reduction splayed the tiller angle. Furthermore, since another AGP gene called OsAGPL3 was expressed at considerable levels in graviresponding sites, we generated a double mutant lacking both OsAGPL1 and OsAGPL3. The double mutant exhibited still lower stem-starch content, less sensitive gravitropic response and greater tiller angle spread than the single mutants. This indicated that the expansion of the tiller angle caused by the reduction in starch level was intense according to the extent of the reduction. We found there were no significant differences between the double mutant and wild-type plants in terms of dry matter production. These results provided new insight into the importance of stem-starch accumulation and ideal plant architecture.

scholarly journals Increasing Starch Accumulation via Genetic Modification of the ADP-glucose Pyrophosphorylase

2009 ◽  
Author(s):  
Arthur Schaffer ◽  
Jack Preiss ◽  
Marina Petreikov ◽  
Ilan Levin
Keyword(s):  
Starch Content ◽  
Large Subunit ◽  
Tomato Fruit ◽  
Sugar Content ◽  
Soluble Sugar ◽  
Starch Synthesis ◽  
Regulatory Subunit ◽  
Starch Accumulation ◽  
Research Project ◽  
Immature Fruit

The overall objective of the research project was to utilize biochemical insights together with both classical and molecular genetic strategies to improve tomato starch accumulation. The proposal was based on the observation that the transient starch accumulation in the immature fruit serves as a reservoir for carbohydrate and soluble sugar content in the mature fruit, thereby impacting on fruit quality. The general objectives were to optimize AGPase function and activity in developing fruit in order to increase its transient starch levels. The specific research objectives were to: a) perform directed molecular evolution of the limiting enzyme of starch synthesis, AGPase, focussing on the interaction of its regulatory and catalytic subunits; b) determine the mode of action of the recently identified allelic variant for the regulatory subunit in tomato fruit that leads to increased AGPase activity and hence starch content. During the course of the research project major advances were made in understanding the interaction of the small and large subunits of AGPase, in particular the regulatory roles of the different large subunits, in determining starch synthesis. The research was performed using various experimental systems, including bacteria and Arabidopsis, potato and tomato, allowing for broad and meaningful conclusions to be drawn. A novel discovery was that one of the large subunits of tomato AGPase is functional as a monomer. A dozen publications describing the research were published in leading biochemical and horticultural journals. The research results clearly indicated that increasing AGPase activity temporally in the developing fruit increase the starch reservoir and, subsequently, the fruit sugar content. This was shown by a comparison of the carbohydrate balance in near-isogenic tomato lines differing in a gene encoding for the fruit-specific large subunit (LS1). The research also revealed that the increase in AGPase activity is due to a temporal extension of LS1 gene expression in the developing fruit which in turn stabilizes the limiting heterotetrameric enzyme, leading to sustained starch synthesis. This genetic variation can successfully be utilized in the breeding of high quality tomatoes.

Molecular Cloning and Spatial Expression of an ApL1 cDNA for the Large Subunit of ADP-Glucose Pyrophosphorylase from Arabidopsis thaliana

1999 ◽  
Vol 54 (5-6) ◽  
pp. 353-358 ◽  
Author(s):  
Leszek A. Kleszkowski ◽  
Lubomir N. Sokolov ◽  
Cheng Luo ◽  
Per Villand
Keyword(s):  
Arabidopsis Thaliana ◽  
Large Subunit ◽  
Critical Role ◽  
Starch Synthesis ◽  
Transit Peptide ◽  
Homologous Proteins ◽  
Peptide Cleavage ◽  
Reading Frame ◽  
Calculated Molecular Weight ◽  
Adp Glucose Pyrophosphorylase

Abstract A cDNA, A p L 1a , corresponding to a homologue of the large subunit of ADP-glucose pyrophosphorylase (AG Pase), has been isolated/characterised by screening a cDNA library prepared from leaves of Arabidopsis thaliana, followed by rapid amplification of cDNA 3′-ends (3′-RACE). Within the 1685 nucleotide-long sequence (excluding polyA tail), an open reading frame encodes a protein of 522 amino acids (aa), with a calculated molecular weight of 57.7 kDa. The derived aa sequence does not contain any discernible transit peptide cleavage site motif, similarly to two other recently sequenced full-length Arabidopsis homo-logues for AGPase, and shows ca. 58–78 % identity to homologous proteins from other plants/tissues. The corresponding gene was found (rosette and stem leaves, stems, flowers and fruits), consistent with its critical role in starch synthesis in

Effects of Elevated Temperature and Reduced Water Uptake on Enzymes of Starch Synthesis in Developing Wheat Grains

1990 ◽  
Vol 17 (4) ◽  
pp. 431 ◽  
Author(s):  
CY Caley ◽  
CM Duffus ◽  
B Jeffcoat
Keyword(s):  
Elevated Temperatures ◽  
Starch Content ◽  
Starch Synthesis ◽  
Dry Weight ◽  
Endosperm Development ◽  
Starch Synthase ◽  
Temperature Regimes ◽  
Endosperm Starch ◽  
Rate Limiting ◽  
Reduced Water

The mechanism of temperature regulation of endosperm development has been investigated by studying the effects of two temperature regimes on starch deposition and starch synthase activity during grain development in two cultivars of wheat. Most of the starch synthase activity was present throughout development as the granule-bound form using ADPglucose as the principal substrate. That starch synthase may be a rate-limiting enzyme for accumulation of starch, and hence dry weight, is suggested by: (1) rates are proportionately less in the cultivar with the lower final endosperm dry weight; (2) at elevated temperatures when starch content and dry weight are reduced, starch synthase activity falls; (3) the rate of starch deposition calculated to be possible from measured rates of starch synthase activity is close to the observed rate of starch deposition. On the other hand, it was concluded that it is not lack of starch synthase activity that causes termination of starch deposition, since activity is maintained well after starch deposition has ceased. Using the same two wheat cultivars, grown as detached ears in liquid culture, the effects of reduced endosperm water content, induced by the presence of polyethylene glycol in the culture medium, were investigated. Endosperm starch synthase activity was unaffected but ADPglucose pyrophosphorylase activity was greatly reduced, suggesting a possible role in the termination of starch synthesis.

scholarly journals Starch synthesis and gelatinization properties of potato tubers

2022 ◽  
Vol 52 (4) ◽  
Author(s):  
Wang Su ◽  
Guangji Ye ◽  
Yun Zhou ◽  
Jian Wang
Keyword(s):  
Gene Expression ◽  
Enzyme Activity ◽  
Starch Granule ◽  
Starch Content ◽  
Starch Synthesis ◽  
Starch Accumulation ◽  
Enzyme Gene ◽  
Middle Stage ◽  
Pasting Temperature ◽  
Starch Synthesis Enzyme

ABSTRACT: Biosynthesis is the only source of potato starch which is an important raw material for food processing, modified starch and biomass energy. However, it is not clear about the evolution of starch synthesis with tuber development in potato. The present study evaluated the differences of starch synthesis and gelatinization properties of potato tubers with different starch content. Relative to cultivars of medium and low starch content, cultivars of high starch content showed significantly higher SBEII gene expression, AGPase and SSS enzyme activity, and total starch content after middle stage of starch accumulation, and had smaller average starch granule size during whole process of tuber development, and had higher pasting temperature before late stages of tuber growth, and had lower pasting temperature after middle stage of starch accumulation. Path analysis showed that, after middle stage of starch accumulation, effects on starch gelatinization of cultivars with high, medium and low starch content represented starch synthesis enzyme activity > starch accumulation > starch granule distribution > starch synthesis enzyme gene expression, starch synthesis enzyme gene expression > starch synthesis enzyme activity > starch accumulation > starch granule distribution, starch synthesis enzyme gene expression > starch granule distribution > starch synthesis enzyme activity > starch accumulation, respectively. In the study, phases existed in the starch biosynthesis of potato tuber, and the starch quality and its formation process were different among varieties with different starch content. The findings might contribute to starch application and potato industries.

scholarly journals Expression of Maize MADS Transcription Factor ZmES22 Negatively Modulates Starch Accumulation in Rice Endosperm

2019 ◽  
Vol 20 (3) ◽  
pp. 483 ◽  
Author(s):  
Kangyong Zha ◽  
Haoxun Xie ◽  
Min Ge ◽  
Zimeng Wang ◽  
Yu Wang ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Mrna Expression ◽  
Starch Content ◽  
Soluble Sugar ◽  
Starch Synthesis ◽  
Synthesis Process ◽  
Starch Accumulation ◽  
Rice Grain ◽  
Altered Expression ◽  
Rice Endosperm

As major component in cereals grains, starch has been one of the most important carbohydrate consumed by a majority of world’s population. However, the molecular mechanism for regulation of biosynthesis of starch remains elusive. In the present study, ZmES22, encoding a MADS-type transcription factor, was modestly characterized from maize inbred line B73. ZmES22 exhibited high expression level in endosperm at 10 days after pollination (DAP) and peaked in endosperm at 20 DAP, indicating that ZmES22 was preferentially expressed in maize endosperm during active starch synthesis. Transient expression of ZmES22 in tobacco leaf revealed that ZmES22 protein located in nucleus. No transactivation activity could be detected for ZmES22 protein via yeast one-hybrid assay. Transformation of overexpressing plasmid 35S::ZmES22 into rice remarkedly reduced 1000-grain weight as well as the total starch content, while the soluble sugar was significantly higher in transgenic rice lines. Moreover, overexpressing ZmES22 reduced fractions of long branched starch. Scanning electron microscopy images of transverse sections of rice grains revealed that altered expression of ZmES22 also changed the morphology of starch granule from densely packed, polyhedral starch granules into loosely packed, spherical granules with larger spaces. Furthermore, RNA-seq results indicated that overexpressing ZmES22 could significantly influence mRNA expression levels of numerous key regulatory genes in starch synthesis pathway. Y1H assay illustrated that ZmES22 protein could bind to the promoter region of OsGIF1 and downregulate its mRNA expression during rice grain filling stages. These findings suggest that ZmES22 was a novel regulator during starch synthesis process in rice endosperm.

A mutant of rice lacking the leaf large subunit of ADP-glucose pyrophosphorylase has drastically reduced leaf starch content but grows normally

2007 ◽  
Vol 34 (6) ◽  
pp. 480 ◽  
Author(s):  
Sandrine Rösti ◽  
Brendan Fahy ◽  
Kay Denyer
Keyword(s):  
Environmental Conditions ◽  
No Reduction ◽  
Starch Content ◽  
Large Subunit ◽  
Starch Synthesis ◽  
Small Subunit ◽  
Wild Type ◽  
Gene Encoding ◽  
Subunit Protein ◽  
Adp Glucose Pyrophosphorylase

A mutant of rice was identified with a Tos17 insertion in OsAPL1, a gene encoding a large subunit (LSU) of ADP-glucose pyrophosphorylase (AGPase). The insertion prevents production of a normal transcript from OsAPL1. Characterisation of the mutant (apl1) showed that the LSU encoded by OsAPL1 is required for AGPase activity in rice leaf blades. In mutant leaf blades, the AGPase small subunit protein is not detectable and the AGPase activity and starch content are reduced to <1 and <5% of that in wild type blades, respectively. The mutation also leads to a reduction in starch content in the leaf sheaths but does not significantly affect AGPase activity or starch synthesis in other parts of the plant. The sucrose, glucose and fructose contents of the leaves are not affected by the mutation. Despite the near absence of starch in the leaf blades, apl1 mutant rice plants grow and develop normally under controlled environmental conditions and show no reduction in productivity.

scholarly journals NnABI4-Mediated ABA Regulation of Starch Biosynthesis in Lotus (Nelumbo nucifera Gaertn)

2021 ◽  
Vol 22 (24) ◽  
pp. 13506
Author(s):  
Peng Wu ◽  
Ailian Liu ◽  
Yongyan Zhang ◽  
Kai Feng ◽  
Shuping Zhao ◽  
...  
Keyword(s):  
Theoretical Basis ◽  
Plant Hormone ◽  
Nuclear Protein ◽  
Starch Content ◽  
Starch Synthesis ◽  
Starch Biosynthesis ◽  
Luciferase Assay ◽  
Starch Accumulation ◽  
Exogenous Aba ◽  
Total Starch

Starch is an important component in lotus. ABA is an important plant hormone, which plays a very crucial role in regulating plant starch synthesis. Using ‘MRH’ as experimental materials, the leaves were sprayed with exogenous ABA before the rhizome expansion. The results showed that stomatal conductance and transpiration rate decreased while net photosynthetic rate increased. The total starch content of the underground rhizome of lotus increased significantly. Meanwhile, qPCR results showed that the relative expression levels of NnSS1, NnSBE1 and NnABI4 were all upregulated after ABA treatment. Then, yeast one-hybrid and dual luciferase assay suggested that NnABI4 protein can promote the expression of NnSS1 by directly binding to its promoter. In addition, subcellular localization results showed that NnABI4 encodes a nuclear protein, and NnSS1 protein was located in the chloroplast. Finally, these results indicate that ABA induced the upregulated expression of NnABI4, and NnABI4 promoted the expression of NnSS1 and thus enhanced starch accumulation in lotus rhizomes. This will provide a theoretical basis for studying the molecular mechanism of ABA regulating starch synthesis in plant.

scholarly journals Physiology of Pea Fruits III. Changes in Starch and-Starch Phosphorylase in the Developing Seed

1957 ◽  
Vol 10 (3) ◽  
pp. 302 ◽  
Author(s):  
Donflla H Turner ◽  
JF Turner
Keyword(s):  
Linear Relationship ◽  
Starch Content ◽  
Starch Synthesis ◽  
Sucrose Content ◽  
Starch Phosphorylase ◽  
Phosphorylase Activity ◽  
Developing Seed ◽  
Pea Seeds ◽  
Starch Formation ◽  
Pea Seed

During the growth of pea seeds there is a period in which the starch content rises rapidly and the sucrose content falls. This paper describes a study of the control of this starch synthesis. A method was developed for the assay of starch phosphorylase in peas and the changes in enzyme activity during development of the pea seed were followed. Over most of the period of development a linear relationship existed between the rate of starch synthesis and starch phosphorylase activity. It is suggested that the activity of starch phosphorylase may be a major factor in controlling the rate of starch formation in the pea. The rate of starch synthesis began to decrease when the pea ceased to gain water and the linear relationship then no longer held. The bearing of these observations on sugar--starch relationships and on the general problems of growth is discussed.

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