Natural variation in rice starch synthase IIa affects enzyme and starch properties

2004 ◽  
Vol 31 (7) ◽  
pp. 671 ◽  
Author(s):  
Takayuki Umemoto ◽  
Noriaki Aoki ◽  
Hongxuan Lin ◽  
Yasunori Nakamura ◽  
Naoyoshi Inouchi ◽  
...  
Keyword(s):  
Amino Acid ◽  
Natural Variation ◽  
Oryza Sativa L ◽  
Length Distribution ◽  
Starch Synthase ◽  
Rice Starch ◽  
Nucleotide Polymorphisms ◽  
Cultivated Rice ◽  
Chain Length Distribution ◽  
Starch Properties

The natural variation in starch synthase IIa (SSIIa) of rice (Oryza sativa L.) was characterised using near-isogenic lines (NILs). SSIIa is a candidate for the alk gene regulating the alkali disintegration of rice grains, since both genes are genetically mapped at the same position on chromosome 6 and related to starch properties. In this study, we report that the alkali-susceptible cultivar Nipponbare lacked SSIIa activity in endosperm. However, the activity was detected with NILs having the alk allele of alkali-tolerant Kasalath. SSIIa protein was present even in Nipponbare endosperm, but it was not associated with starch granules at the milky stage of endosperm. Three single-nucleotide polymorphisms (SNPs) predicting amino acid substitutions existed between the cDNA sequences of SSIIa of Nipponbare and Kasalath were genotyped with 65 rice cultivars and four wild relatives of cultivated rice. The results obtained explain the potential importance of two of the amino acid residues for starch association of rice SSIIa. An analysis of the chain-length distribution of β-limit dextrin of amylopectin showed that without SSIIa activity, the relative number of A-chains (the short chains without branches) increased and that of B1-chains (the short chains with branches) decreased. This suggests that, given the SSIIa defect, short A-chains could not reach a sufficient length for branching enzymes to act on them to produce B1-chains.

Single-nucleotide polymorphisms in rice starch synthase IIa that alter starch gelatinisation and starch association of the enzyme

2005 ◽  
Vol 32 (9) ◽  
pp. 763 ◽  
Author(s):  
Takayuki Umemoto ◽  
Noriaki Aoki
Keyword(s):  
Amino Acid ◽  
Single Nucleotide Polymorphisms ◽  
Oryza Sativa L ◽  
Length Distribution ◽  
Branch Length ◽  
Starch Synthase ◽  
Rice Starch ◽  
Nucleotide Polymorphisms ◽  
Single Nucleotide ◽  
Chain Length Distribution

The starch synthase IIa (SSIIa) gene of rice (Oryza sativa L.) has been shown to be the alk gene that controls alkali disintegration of rice grains, although the effects of naturally occurring alk mutant alleles on enzyme function have yet to be determined. We genotyped 60 rice cultivars for two single-nucleotide polymorphisms (SNPs) in rice SSIIa, including one that results in an amino acid substitution. Incorporating data for three other SNPs previously genotyped in rice SSIIa, five haplotypes were found. We analysed the association of these SSIIa haplotypes with the chain-length distribution of amylopectin, the gelatinisation temperature of rice flour, the alkali spreading score, and the starch association of the enzyme. It was determined that two SNPs resulting in amino acid changes close to the C-terminus most likely alter SSIIa both in terms of activity and starch granule association. This in turn alters the branch-length distribution of amylopectin and the gelatinisation properties of starch.

scholarly journals Competition between Granule Bound Starch Synthase and Starch Branching Enzyme in Starch Biosynthesis

Rice ◽  
2019 ◽  
Vol 12 (1) ◽  
Author(s):  
Huaxin Han ◽  
Chuantian Yang ◽  
Jihui Zhu ◽  
Lixia Zhang ◽  
Yeming Bai ◽  
...  
Keyword(s):  
Functional Properties ◽  
Length Distribution ◽  
Soluble Starch ◽  
Starch Biosynthesis ◽  
Starch Synthase ◽  
Size Exclusion ◽  
Rice Starch ◽  
Rice Varieties ◽  
Chain Length Distribution ◽  
Granule Bound Starch Synthase

Abstract Background Starch branching enzymes (SBE) and granule-bound starch synthase (GBSS) are two important enzymes for starch biosynthesis. SBE mainly contributes to the formation of side branches, and GBSS mainly contributes for the synthesis of amylose molecules. However, there are still gaps in the understanding of possible interactions between SBE and GBSS. Results Nineteen natural rice varieties with amylose contents up to 28% were used. The molecular structure, in the form of the chain-length distribution (CLDs, the distribution of the number of monomer units in each branch) was measured after enzymatic debranching, using fluorophore-assisted carbohydrate electrophoresis for amylopectin and size- exclusion chromatography for amylose. The resulting distributions were fitted to two mathematical models based on the underlying biosynthetic processes, which express the CLDs in terms of parameters reflecting relevant enzyme activities. Conclusions Finding statistically valid correlations between the values of these parameters showed that GBSSI and SBEI compete for substrates during rice starch biosynthesis, and synthesis of amylose short chains involves several enzymes including GBSSI, SBE and SSS (soluble starch synthase). Since the amylose CLD is important for a number of functional properties such as digestion rate, this knowledge is potentially useful for developing varieties with improved functional properties.

Melting the secrets of gelatinisation temperature in rice

2010 ◽  
Vol 37 (5) ◽  
pp. 439 ◽  
Author(s):  
Rosa P. Cuevas ◽  
Venea D. Daygon ◽  
Henry M. Corpuz ◽  
Leilani Nora ◽  
Russell F. Reinke ◽  
...  
Keyword(s):  
Amylose Content ◽  
Oryza Sativa L ◽  
Length Distribution ◽  
Cooking Time ◽  
Scanning Calorimetry ◽  
Rice Varieties ◽  
Chain Length Distribution ◽  
Chain Lengths ◽  
Major Grouping ◽  
Upper Boundary

Gelatinisation temperature (GT) is one of the key traits measured in programs for breeding rice (Oryza sativa L.). It is commonly estimated by the alkali spreading value (ASV), and less commonly by differential scanning calorimetry (DSC). Using a diverse set of germplasm, it was determined that DSC values associate poorly with ASV, are not correlated with amylose content but correlate with cooking time. Rice varieties are traditionally grouped into three classes of GT based on ASV: high, intermediate and low. However, the distribution of DSC values of 4000 samples shows only two classes: high and low. Large differences in the distributions of chain lengths synthesised by starch synthase IIa (SSIIa) support the two classes as the major grouping, two haplotypes associating with each peak. Each peak of DSC values spanned 10°C. The chain length distribution of the amylopectin molecules from varieties at the upper boundary of each peak showed significantly more chains that span both the crystalline and amorphous lamellae of a cluster than varieties at the other end of that distribution. Improved varieties, classified as intermediate GT by ASV, belong to both of the classes defined by DSC, implying that some enzyme, other than SSIIa is involved in intermediate GT.

scholarly journals Effect of biochar on rice starch properties and starch-related gene expression and enzyme activities

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Diankai Gong ◽  
Ximing Xu ◽  
Li’an Wu ◽  
Guijin Dai ◽  
Wenjing Zheng ◽  
...  
Keyword(s):  
Soluble Starch ◽  
Taste Quality ◽  
Starch Synthase ◽  
Rice Starch ◽  
Rice Varieties ◽  
Starch Properties ◽  
Genes Encoding ◽  
Branching Enzymes ◽  
Starch Debranching Enzyme

Abstract We determined the effects of biochar on starch properties and the activities of enzymes and expression levels of genes related to starch in two Japonica rice cultivars. The two rice varieties were subjected to five biochar treatments (0, control; and 5, 10, 20, and 40 t/hm2). In both rice varieties, the content of apparent amylose and resistant starch were lower in biochar treatments than in the control. The proportion of fa chains was higher and that of fb3 chain was lower in the biochar treatments than in the control. Starch viscosity and cooking taste quality were improved by the biochar treatments. In both rice varieties, the activity of granule-bound starch synthase was significantly decreased by biochar treatments, and the activities of soluble starch synthase, starch branching enzyme, and starch debranching enzyme were significantly increased. The transcript levels of genes encoding starch synthases and starch branching enzymes were significantly increased by biochar treatments. We conclude that biochar at a dose of 5–10 t/hm2 can regulate the activity of starch-related enzymes, and this affects the type, content, and fine structure of starch. Therefore, the addition of biochar to soil can improve the viscosity and taste quality of rice starch.

scholarly journals Pathway of Cytosolic Starch Synthesis in the Model Glaucophyte Cyanophora paradoxa

2007 ◽  
Vol 7 (2) ◽  
pp. 247-257 ◽  
Author(s):  
Charlotte Plancke ◽  
Christophe Colleoni ◽  
Philippe Deschamps ◽  
David Dauvillée ◽  
Yasunori Nakamura ◽  
...  
Keyword(s):  
Starch Synthesis ◽  
Length Distribution ◽  
Soluble Starch ◽  
Land Plant ◽  
Starch Synthase ◽  
Cyanophora Paradoxa ◽  
Chain Length Distribution ◽  
Photosynthetic Eukaryotes ◽  
A Chain

ABSTRACT The nature of the cytoplasmic pathway of starch biosynthesis was investigated in the model glaucophyte Cyanophora paradoxa. The storage polysaccharide granules are shown to be composed of both amylose and amylopectin fractions, with a chain length distribution and crystalline organization similar to those of green algae and land plant starch. A preliminary characterization of the starch pathway demonstrates that Cyanophora paradoxa contains several UDP-glucose-utilizing soluble starch synthase activities related to those of the Rhodophyceae. In addition, Cyanophora paradoxa synthesizes amylose with a granule-bound starch synthase displaying a preference for UDP-glucose. A debranching enzyme of isoamylase specificity and multiple starch phosphorylases also are evidenced in the model glaucophyte. The picture emerging from our biochemical and molecular characterizations consists of the presence of a UDP-glucose-based pathway similar to that recently proposed for the red algae, the cryptophytes, and the alveolates. The correlative presence of isoamylase and starch among photosynthetic eukaryotes is discussed.

scholarly journals Pasting Properties of Various Waxy Rice Flours: Effect of α-Amylase Activity, Protein, and Amylopectin

2021 ◽  
Author(s):  
Yuehui Wang ◽  
Kuijie Sun ◽  
Wenchang Zhu ◽  
Wenping Ding ◽  
Qingyun Lyu ◽  
...  
Keyword(s):  
Amylase Activity ◽  
Length Distribution ◽  
Pasting Properties ◽  
Alpha Amylase ◽  
Rice Starch ◽  
Rice Varieties ◽  
Relative Crystallinity ◽  
Chain Length Distribution ◽  
Waxy Rice ◽  
Rice Flours

Waxy rice is one of the most popular traditional crops served as a staple food in China. In this study, the effect of different factors including α-amylase activity, protein, and amylopectin structure on the pasting properties of four waxy rice varieties were investigated. Rice flours treated with AgNO3 solution, DL-dithiothreitol (DTT) or protease, suggested that both α-amylase activity and protein significantly decrease the pasting viscosity of waxy rice flours. Chain length distribution of amylopectin as measured by high performance ion exchange chromatography (HPAEC-PAD) showed that starch with higher ratio of short chain leading to a higher pasting viscosity. X-Ray diffractograms showed that the crystal type of all the four varieties of rice starches were characteristic A-type. Relative crystallinity of each rice starch was further calculated, and a higher crystallization resulted in a higher viscosity. Our study would provide a fundamental knowledge of the relationship between different factors and waxy starch pasting properties, as well as be a reference for controlling the quality of waxy rice starch-based food.

scholarly journals The Wzz (Cld) Protein in Escherichia coli: Amino Acid Sequence Variation Determines O-Antigen Chain Length Specificity

1998 ◽  
Vol 180 (10) ◽  
pp. 2670-2675 ◽  
Author(s):  
Agustin V. Franco ◽  
Dan Liu ◽  
Peter R. Reeves
Keyword(s):  
Escherichia Coli ◽  
Amino Acid ◽  
Amino Acid Sequence ◽  
Chain Length ◽  
Sequence Variation ◽  
Length Distribution ◽  
Chain Length Distribution ◽  
E Coli ◽  
O Antigen ◽  
Amino Acid Sequence Variation

ABSTRACT The O antigen is a polymer with a repeated unit. The chain length in most Escherichia coli strains has a modal value of 10 to 18 O units, but other strains have higher or lower modal values.wzz (cld/rol) mutants have a random chain length distribution, showing that the modal distribution is determined by the Wzz protein. Cloned wzz genes from E. coli strains with short (7 to 16), intermediate (10 to 18), and long (16 to 25) modal chain lengths were transferred to a model system, and their effects on O111 antigen were studied. The O111 chain length closely resembled that of the parent strains. We present data based on the construction of chimeric wzz genes and site-directed mutagenesis of the wzz gene to show that the modal value of O-antigen chain length of E. coli O1, O2, O7, and O157 strains can be changed by specific amino acid substitutions in wzz. It is concluded that the O-antigen chain length heterogeneity in E. coli strains is the result of amino acid sequence variation of the Wzz protein.

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