Starch Biosynthesis in Higher Plants

2011 ◽  
pp. 47-65 ◽  
Author(s):  
I.J. Tetlow ◽  
M.J. Emes
Keyword(s):  
Higher Plants ◽  
Starch Biosynthesis

scholarly journals Molecular Functions and Pathways of Plastidial Starch Phosphorylase (PHO1) in Starch Metabolism: Current and Future Perspectives

2021 ◽  
Vol 22 (19) ◽  
pp. 10450
Author(s):  
Noman Shoaib ◽  
Lun Liu ◽  
Asif Ali ◽  
Nishbah Mughal ◽  
Guowu Yu ◽  
...  
Keyword(s):  
Protein Interactions ◽  
Molecular Mechanisms ◽  
Higher Plants ◽  
Crop Improvement ◽  
Starch Biosynthesis ◽  
Starch Metabolism ◽  
Protein Protein Interactions ◽  
Starch Phosphorylase ◽  
Integral Role

Starch phosphorylase is a member of the GT35-glycogen-phosphorylase superfamily. Glycogen phosphorylases have been researched in animals thoroughly when compared to plants. Genetic evidence signifies the integral role of plastidial starch phosphorylase (PHO1) in starch biosynthesis in model plants. The counterpart of PHO1 is PHO2, which specifically resides in cytosol and is reported to lack L80 peptide in the middle region of proteins as seen in animal and maltodextrin forms of phosphorylases. The function of this extra peptide varies among species and ranges from the substrate of proteasomes to modulate the degradation of PHO1 in Solanum tuberosum to a non-significant effect on biochemical activity in Oryza sativa and Hordeum vulgare. Various regulatory functions, e.g., phosphorylation, protein–protein interactions, and redox modulation, have been reported to affect the starch phosphorylase functions in higher plants. This review outlines the current findings on the regulation of starch phosphorylase genes and proteins with their possible role in the starch biosynthesis pathway. We highlight the gaps in present studies and elaborate on the molecular mechanisms of phosphorylase in starch metabolism. Moreover, we explore the possible role of PHO1 in crop improvement.

BIOSYNTHESIS AND DEGRADATION OF STARCH IN HIGHER PLANTS

2020 ◽  
Author(s):  
Lungwani Muungo
Keyword(s):  
Higher Plants ◽  
Starch Biosynthesis ◽  
Metabolizing Enzymes ◽  
Transitory Starch ◽  
Leaf Tissues ◽  
Cellular Compartments

Numerous reviews on starch biosynthesis and degradation have appeared inthe 1980s (4, 23, 39, 40, 51, 73, 100, 101, 124, 125). Here we updateestablished concepts and emphasize three topics that we consider to now meritreexamination: the significance of enzyme multiplicity, a comparison ofdegradation of reserve and transitory starch, and the localization of starchdegrading enzymes in starch-free cellular compartments of leaf tissues. Westress the cell physiological aspects of starch metabolizing enzymes.

scholarly journals PDIL1-2 can indirectly and negatively regulate expression of the AGPL1 gene in bread wheat

2019 ◽  
Vol 52 (1) ◽  
Author(s):  
Jie Dong ◽  
Yongxing Zheng ◽  
Yihan Fu ◽  
Jinxi Wang ◽  
Shasha Yuan ◽  
...  
Keyword(s):  
Higher Plants ◽  
Large Subunit ◽  
Functional Characterization ◽  
Starch Biosynthesis ◽  
Kernel Weight ◽  
Starch Accumulation ◽  
Virus Induced Gene Silencing ◽  
Gene Encoding ◽  
Key Enzyme ◽  
And Function

Abstract Background ADP-glucose pyrophosphorylase (AGPase), the key enzyme in plant starch biosynthesis, is a heterotetramer composed of two identical large subunits and two identical small subunits. AGPase has plastidial and cytosolic isoforms in higher plants, whereas it is mainly detected in the cytosol of grain endosperms in cereal crops. Our previous results have shown that the expression of the TaAGPL1 gene, encoding the cytosolic large subunit of wheat AGPase, temporally coincides with the rate of starch accumulation and that its overexpression dramatically increases wheat AGPase activity and the rate of starch accumulation, suggesting an important role. Methods In this study, we performed yeast one-hybrid screening using the promoter of the TaAGPL1 gene as bait and a wheat grain cDNA library as prey to screen out the upstream regulators of TaAGPL1 gene. And the barley stripe mosaic virus-induced gene-silencing (BSMV-VIGS) method was used to verify the functional characterization of the identified regulators in starch biosynthesis. Results Disulfide isomerase 1-2 protein (TaPDIL1-2) was screened out, and its binding to the TaAGPL1-1D promoter was further verified using another yeast one-hybrid screen. Transiently silenced wheat plants of the TaPDIL1-2 gene were obtained by using BSMV-VIGS method under field conditions. In grains of BSMV-VIGS-TaPDIL1-2-silenced wheat plants, the TaAGPL1 gene transcription levels, grain starch contents, and 1000-kernel weight also significantly increased. Conclusions As important chaperones involved in oxidative protein folding, PDIL proteins have been reported to form hetero-dimers with some transcription factors, and thus, our results suggested that TaPDIL1-2 protein could indirectly and negatively regulate the expression of the TaAGPL1 gene and function in starch biosynthesis.

Subcellular Localization of Amylose Precipitating Factor in Neurospora

1982 ◽  
Vol 40 ◽  
pp. 312-313
Author(s):  
Jacob P. Varkey ◽  
Mathew J. Nadakavukaren ◽  
Derek A. McCracken
Keyword(s):  
Subcellular Localization ◽  
Higher Plants ◽  
Starch Biosynthesis ◽  
Short Chain ◽  
Distinguishing Characteristic ◽  
Fungal Hyphae ◽  
Precipitating Factor

Amylose precipitating factor (APF) is a lipoprotein first found associated with starch in some fungi. Since then, APF has been reported from many organisms. The ability of the lipoprotein to bind to short chain amylose molecules and precipitate them is used as a distinguishing characteristic. Starch produced by certain fungi consists of short chain amylose molecules. Even though these fungi have the enzymes needed for the formation of large amylose molecules as in higher plants, the reason for the formation of short chain amylose is not known. Since APF is associated with short chain amylose molecules, we were interested in studying the effect of APF on the fungal starch biosynthesis. In this paper we describe the localization of APF in the fungal hyphae.

In vitro and in vivo polysaccharides assembly: ultrastructural and cytochemical study of growing plant cell wall components.

1978 ◽  
Vol 36 (2) ◽  
pp. 434-435
Author(s):  
D. Reis ◽  
B. Vian ◽  
J. C. Roland
Keyword(s):  
Cell Wall ◽  
Self Assembly ◽  
Plant Cell Wall ◽  
Higher Plants ◽  
Three Dimensional ◽  
Cytochemical Study ◽  
Wall Components

Wall morphogenesis in higher plants is a problem still open to controversy. Until now the possibility of a transmembrane control and the involvement of microtubules were mostly envisaged. Self-assembly processes have been observed in the case of walls of Chlamydomonas and bacteria. Spontaneous gelling interactions between xanthan and galactomannan from Ceratonia have been analyzed very recently. The present work provides indications that some processes of spontaneous aggregation could occur in higher plants during the formation and expansion of cell wall.Observations were performed on hypocotyl of mung bean (Phaseolus aureus) for which growth characteristics and wall composition have been previously defined.In situ, the walls of actively growing cells (primary walls) show an ordered three-dimensional organization (fig. 1). The wall is typically polylamellate with multifibrillar layers alternately transverse and longitudinal. Between these layers intermediate strata exist in which the orientation of microfibrils progressively rotates. Thus a progressive change in the morphogenetic activity occurs.

Localization of Adenosine Triphosphatase Activity in the Phleom of Nicotiana Tabacum

1972 ◽  
Vol 30 ◽  
pp. 230-231
Author(s):  
James Cronshaw ◽  
Jamison E. Gilder
Keyword(s):  
Plasma Membrane ◽  
Atpase Activity ◽  
Adenosine Triphosphatase ◽  
Higher Plants ◽  
High Surface ◽  
Root Tip ◽  
Animal Cells ◽  
Physiological Processes ◽  
Tip Cells ◽  
Atpase Localization

Adenosine triphosphatase (ATPase) activity has been shown to be associated with numerous physiological processes in both plants and animal cells. Biochemical studies have shown that in higher plants ATPase activity is high in cell wall preparations and is associated with the plasma membrane, nuclei, mitochondria, chloroplasts and lysosomes. However, there have been only a few ATPase localization studies of higher plants at the electron microscope level. Poux (1967) demonstrated ATPase activity associated with most cellular organelles in the protoderm cells of Cucumis roots. Hall (1971) has demonstrated ATPase activity in root tip cells of Zea mays. There was high surface activity largely associated with the plasma membrane and plasmodesmata. ATPase activity was also demonstrated in mitochondria, dictyosomes, endoplasmic reticulum and plastids.

A Scanning Electron Microscopic Study of Pro-Vascular Cellular Morphology in Chaetophora Incressata

1985 ◽  
Vol 43 ◽  
pp. 638-639
Author(s):  
A. E. Hotchkiss ◽  
A. T. Hotchkiss ◽  
R. P. Apkarian
Keyword(s):  
Green Algae ◽  
Vascular Plants ◽  
Vascular System ◽  
Higher Plants ◽  
Wall Structure ◽  
Electron Microscopic ◽  
Physiological Processes ◽  
Scanning Electron Microscopic Study ◽  
Scanning Electron Microscopic ◽  
Scanning Electron

Multicellular green algae may be an ancestral form of the vascular plants. These algae exhibit cell wall structure, chlorophyll pigmentation, and physiological processes similar to those of higher plants. The presence of a vascular system which provides water, minerals, and nutrients to remote tissues in higher plants was believed unnecessary for the algae. Among the green algae, the Chaetophorales are complex highly branched forms that might require some means of nutrient transport. The Chaetophorales do possess apical meristematic groups of cells that have growth orientations suggestive of stem and root positions. Branches of Chaetophora incressata were examined by the scanning electron microscope (SEM) for ultrastructural evidence of pro-vascular transport.

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