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BMC Plant Biology Oct 2021Starch branching enzymes (SBEs) are key determinants of the structure and amount of the starch in plant organs, and as such, they have the capacity to influence plant... (Review)
Review
Starch branching enzymes (SBEs) are key determinants of the structure and amount of the starch in plant organs, and as such, they have the capacity to influence plant growth, developmental, and fitness processes, and in addition, the industrial end-use of starch. However, little is known about the role of SBEs in determining starch structure-function relations in economically important horticultural crops such as fruit and leafy greens, many of which accumulate starch transiently. Further, a full understanding of the biological function of these types of starches is lacking. Because of this gap in knowledge, this minireview aims to provide an overview of SBEs in horticultural crops, to investigate the potential role of starch in determining postharvest quality. A systematic examination of SBE sequences in 43 diverse horticultural species, identified SBE1, 2 and 3 isoforms in all species examined except apple, olive, and Brassicaceae, which lacked SBE1, but had a duplicated SBE2. Among our findings after a comprehensive and critical review of published data, was that as apple, banana, and tomato fruits ripens, the ratio of the highly digestible amylopectin component of starch increases relative to the more digestion-resistant amylose fraction, with parallel increases in SBE2 transcription, fruit sugar content, and decreases in starch. It is tempting to speculate that during the ripening of these fruit when starch degradation occurs, there are rearrangements made to the structure of starch possibly via branching enzymes to increase starch digestibility to sugars. We propose that based on the known action of SBEs, and these observations, SBEs may affect produce quality, and shelf-life directly through starch accumulation, and indirectly, by altering sugar availability. Further studies where SBE activity is fine-tuned in these crops, can enrich our understanding of the role of starch across species and may improve horticulture postharvest quality.
Topics: 1,4-alpha-Glucan Branching Enzyme; Amino Acid Motifs; Amylopectin; Amylose; Crops, Agricultural; Edible Grain; Food Storage; Fruit; Horticulture; Isoenzymes; Phylogeny; Plant Proteins; Plant Tubers; Starch; Sugars; Vegetables
PubMed: 34674662
DOI: 10.1186/s12870-021-03253-6 -
The Plant Genome Sep 2022Understanding the genetic control and inheritance of grain quality traits is instrumental in facilitating end-use quality improvement. This study was conducted to...
Understanding the genetic control and inheritance of grain quality traits is instrumental in facilitating end-use quality improvement. This study was conducted to identify and map quantitative trait loci (QTL) controlling protein, starch, and amylose content in grain sorghum [Sorghum bicolor (L.) Moench] grown under variable environmental conditions. A recombinant inbred line (RIL) population derived from a cross between RTx430 and SC35 was evaluated in six environments across Hays and Manhattan, KS. Significant variation was observed in genotype, environment, and genotype × environment interaction for all three quality traits. Unlike the RILs, the two parental lines did not show significant differences for these traits. However, significant transgressive segregation was observed for all traits resulting in phenotypic performance extending beyond the two parents. A total of seven protein, 10 starch, and 10 amylose content QTL were identified. Chromosomal regions and phenotypic variation (PVE) of QTL were variable across growing conditions. Quantitative trait loci hotspots for all three traits were detected on chromosomes 1 (115.2-119.2 cM) and 2 (118.2-127.4 cM). Candidate gene analysis indicated that these QTL hotspots were conditioned by several transcription factors, such as Cytochrome P450 and basic helix-loop-helix DNA binding protein, which regulate starch and protein accumulation in the grain. The identified genomic regions and underlying candidate genes provide a starting point for further validation and marker-assisted gene pyramiding to improve sorghum grain quality.
Topics: Amylose; Chromosome Mapping; DNA-Binding Proteins; Edible Grain; Quantitative Trait Loci; Sorghum; Starch; Transcription Factors
PubMed: 35880472
DOI: 10.1002/tpg2.20227 -
PloS One 2021Many studies have been carried out on N sources effect on fragrant rice; however, their impact on rice grain quality is largely unclear. In this study, we evaluated the...
Many studies have been carried out on N sources effect on fragrant rice; however, their impact on rice grain quality is largely unclear. In this study, we evaluated the effects of different types of N sources on rice growth, yield, 2-acetyl-1-pyrroline (2AP), amylose and cooked rice elongation. Two indica rice cultivars, Basmati 385 (B385), Xiangyaxiangzhan (XYXZ) and two japonica cultivars, Yunjingyou (YJY), Daohuaxiang (DHX) were grown in experimental pots with six replications under four N sources: Potassium nitrate (KNO3), ammonium bicarbonate (NH4HCO3), urea (H2NCONH2) and sodium nitrate (NaNO3) in 2019 and 2020 early seasons. Our results showed that N dynamics regulated the number of panicles, 1000-grain weight, grain yield, 2-acetyl-1-pyrroline, amylose and cooked rice elongation across all the four treatments. The NH4HCO3 treatment significantly increased the number of panicles and grain yield across the four rice varieties compared with KNO3, H2NCONH2 and NaNO3 N sources in both 2019 and 2020 early season, The KNO3 treatment significantly showed higher 1000-grain weight in B-385, YJY, XYXZ and DHX compared to other N sources. Compared with other N sources treatment, the NH4HCO3 treatments significantly increased the 2AP contents in heading stage leaves, matured leaves and grains of B-385, YJY, XYXZ and DHX respectively. Cooked rice elongation percentage also showed significant difference in all treatments studied with KNO3 recorded the highest across the four varieties. Analysis of major enzymes and compounds such as P5C, P5CS, PDH, Pyrroline, proline and Methylglyoxal showed remarkable differences in each cultivar at heading and maturity stages with higher activity in NH4HCO3 and H2NCONH2 treatments. Similarly, in all treatments, we also observed significant increase in amylose content percentage, with NH4HCO3 having greater percentage of amylose.
Topics: Amylose; Cooking; Gene Expression Regulation, Plant; Nitrogen; Oryza
PubMed: 34264963
DOI: 10.1371/journal.pone.0254182 -
European Journal of Biochemistry Oct 2003Two inhibitors, acarbose and cyclodextrins (CD), were used to investigate the active site structure and function of barley alpha-amylase isozymes, AMY1 and AMY2. The... (Comparative Study)
Comparative Study
Two inhibitors, acarbose and cyclodextrins (CD), were used to investigate the active site structure and function of barley alpha-amylase isozymes, AMY1 and AMY2. The hydrolysis of DP 4900-amylose, reduced (r) DP18-maltodextrin and maltoheptaose (catalysed by AMY1 and AMY2) was followed in the absence and in the presence of inhibitor. Without inhibitor, the highest activity was obtained with amylose, kcat/Km decreased 103-fold using rDP18-maltodextrin and 10(5) to 10(6)-fold using maltoheptaose as substrate. Acarbose is an uncompetitive inhibitor with inhibition constant (L1i) for amylose and maltodextrin in the micromolar range. Acarbose did not bind to the active site of the enzyme, but to a secondary site to give an abortive ESI complex. Only AMY2 has a second secondary binding site corresponding to an ESI2 complex. In contrast, acarbose is a mixed noncompetitive inhibitor of maltoheptaose hydrolysis. Consequently, in the presence of this oligosaccharide substrate, acarbose bound both to the active site and to a secondary binding site. alpha-CD inhibited the AMY1 and AMY2 catalysed hydrolysis of amylose, but was a very weak inhibitor compared to acarbose.beta- and gamma-CD are not inhibitors. These results are different from those obtained previously with PPA. However in AMY1, as already shown for amylases of animal and bacterial origin, in addition to the active site, one secondary carbohydrate binding site (s1) was necessary for activity whereas two secondary sites (s1 and s2) were required for the AMY2 activity. The first secondary site in both AMY1 and AMY2 was only functional when substrate was bound in the active site. This appears to be a general feature of the alpha-amylase family.
Topics: Acarbose; Amylose; Binding Sites; Cyclodextrins; Enzyme Inhibitors; Glucans; Hordeum; Hydrolysis; Isoenzymes; Kinetics; Polysaccharides; Spectrophotometry; Structure-Activity Relationship; Substrate Specificity; alpha-Amylases
PubMed: 14511369
DOI: 10.1046/j.1432-1033.2003.03733.x -
International Journal of Molecular... Apr 2022Potato ( L.) is the third most important food crop after rice and wheat. Its tubers are a rich source of dietary carbohydrates in the form of starch, which has many...
Potato ( L.) is the third most important food crop after rice and wheat. Its tubers are a rich source of dietary carbohydrates in the form of starch, which has many industrial applications. Starch is composed of two polysaccharides, amylose and amylopectin, and their ratios determine different properties and functionalities. Potato varieties with higher amylopectin have many food processing and industrial applications. Using -mediated transformation, we delivered Clustered regularly interspaced short palindromic repeats and CRISPR-associated protein 9 (CRISPR/Cas9) reagents to potato (variety Yukon Gold) cells to disrupt the granule-bound starch synthase () gene with the aim of eliminating the amylose component of starch. Lugol-Iodine staining of the tubers showed a reduction or complete elimination of amylose in some of the edited events. These results were further confirmed by the perchloric acid and enzymatic methods. One event (T2-7) showed mutations in all four alleles and total elimination of amylose from the tubers. Viscosity profiles of the tuber starch from six different knockout events were determined using a Rapid Visco Analyzer (RVA), and the values reflected the amylopectin/amylose ratio. Follow-up studies will focus on eliminating the CRISPR components from the events and on evaluating the potential of clones with various amylose/amylopectin ratios for food processing and other industrial applications.
Topics: Amylopectin; Amylose; CRISPR-Cas Systems; Gold; Mutagenesis; Solanum tuberosum; Starch; Starch Synthase; Yukon Territory
PubMed: 35563030
DOI: 10.3390/ijms23094640 -
Ultrasonics Sonochemistry Dec 2019High-amylose starch is in great demand in the food industry due to its unique functional properties but has very limited source. In this study, high-amylose starch was...
High-amylose starch is in great demand in the food industry due to its unique functional properties but has very limited source. In this study, high-amylose starch was successfully extracted from Radix Puerariae using ultrasound extraction. The effects of ultrasound intensity (15.29, 20.38, 22.93, 24.46 and 25.38 kW/m) and frequency (20 and 45 kHz) on extraction kinetics, and chemical compositions, crystallinity, in vitro digestion behaviour and gelling properties of starches were investigated. It was shown that with the increasing intensity, the extraction rate and content of amylose increased, but for starch the extraction rate increased initially until reached a plateau at an intensity of 24.46 kW/m. With the increasing low-frequency, the extraction rate and content of amylose increased, but the extraction rate of starch decreased. Based on statistical tests, the Logistic model was found to fit well to the extraction kinetics of amylose, and the Peleg model fit well to that of starch. The extraction yield of starch was not significantly affected by ultrasound conditions. The obtained starch has a high-purity with a content of more than 99% dry basis and an unchanged crystallinity. Moreover, the increased amylose content resulted in an increase of the content of slowly digestible starch, resistant starch, and gelling hardness. This study demonstrates that high-amylose starch can be obtained using ultrasound extraction from Radix Puerariae at high-intensity low-frequency.
Topics: Amylose; Chemical Fractionation; Digestion; Kinetics; Pueraria; Starch; Ultrasonic Waves
PubMed: 31421611
DOI: 10.1016/j.ultsonch.2019.104710 -
Ultrasonics Sonochemistry Aug 2021In this study, the effects of sonication and temperature-cycled storage on the structural properties and resistant starch content of high-amylose corn starch were...
In this study, the effects of sonication and temperature-cycled storage on the structural properties and resistant starch content of high-amylose corn starch were investigated. Sonication induced a partial depolymerization of the molecular structures of amylopectin and amylose. Sonication treatment induced the appropriate structural changes for retrogradation. Although the relative crystallinity of sonicated starch was lower than that of non-sonicated starch, sonicated starch after retrogradation showed much higher relative crystallinity than non-sonicated starch. Regardless of sonication treatment, temperature-cycled storage resulted in a higher degree of retrogradation than isothermal storage, but the rate of retrogradation was greater in sonicated starch than in non-sonicated starch, as supported by retrogradation enthalpy, the Avrami constant, and relative crystallinity. The highly developed crystalline structure in sonicated starches due to retrogradation was reflected by the large amount of resistant starch.
Topics: Amylose; Kinetics; Sonication; Temperature
PubMed: 34182316
DOI: 10.1016/j.ultsonch.2021.105650 -
Plant Biotechnology Journal Feb 2018Starch is the most abundant storage carbohydrate in maize kernel. The content of amylose and amylopectin confers unique properties in food processing and industrial...
Starch is the most abundant storage carbohydrate in maize kernel. The content of amylose and amylopectin confers unique properties in food processing and industrial application. Thus, the resurgent interest has been switched to the study of individual amylose or amylopectin rather than total starch, whereas the enzymatic machinery for amylose synthesis remains elusive. We took advantage of the phenotype of amylose content and the genotype of 9,007,194 single nucleotide polymorphisms from 464 inbred maize lines. The genome-wide association study identified 27 associated loci involving 39 candidate genes that were linked to amylose content including transcription factors, glycosyltransferases, glycosidases, as well as hydrolases. Except the waxy gene that encodes the granule-bound starch synthase, the remaining candidate genes were located in the upstream pathway of amylose synthesis, while the downstream members were already known from prior studies. The linked candidate genes could be transferred to manipulate amylose content and thus add value to maize kernel in the breeding programme.
Topics: Amylose; Gene Expression Regulation, Plant; Genome-Wide Association Study; Polymorphism, Single Nucleotide; Zea mays
PubMed: 28796926
DOI: 10.1111/pbi.12821 -
BMC Plant Biology Oct 2016Starch is a major part of cereal grain. It comprises two glucose polymer fractions, amylose (AM) and amylopectin (AP), that make up about 25 and 75 % of total starch,...
Development of EMS-induced mutation population for amylose and resistant starch variation in bread wheat (Triticum aestivum) and identification of candidate genes responsible for amylose variation.
BACKGROUND
Starch is a major part of cereal grain. It comprises two glucose polymer fractions, amylose (AM) and amylopectin (AP), that make up about 25 and 75 % of total starch, respectively. The ratio of the two affects processing quality and digestibility of starch-based food products. Digestibility determines nutritional quality, as high amylose starch is considered a resistant or healthy starch (RS type 2) and is highly preferred for preventive measures against obesity and related health conditions. The topic of nutrition security is currently receiving much attention and consumer demand for food products with improved nutritional qualities has increased. In bread wheat (Triticum aestivum L.), variation in amylose content is narrow, hence its limited improvement. Therefore, it is necessary to produce wheat lines or populations showing wide variation in amylose/resistant starch content. In this study, a set of EMS-induced M4 mutant lines showing dynamic variation in amylose/resistant starch content were produced. Furthermore, two diverse mutant lines for amylose content were used to study quantitative expression patterns of 20 starch metabolic pathway genes and to identify candidate genes for amylose biosynthesis.
RESULTS
A population comprising 101 EMS-induced mutation lines (M4 generation) was produced in a bread wheat (Triticum aestivum) variety. Two methods of amylose measurement in grain starch showed variation in amylose content ranging from ~3 to 76 % in the population. The method of in vitro digestion showed variation in resistant starch content from 1 to 41 %. One-way ANOVA analysis showed significant variation (p < 0.05) in amylose and resistant starch content within the population. A multiple comparison test (Dunnett's test) showed that significant variation in amylose and resistant starch content, with respect to the parent, was observed in about 89 and 38 % of the mutant lines, respectively. Expression pattern analysis of 20 starch metabolic pathway genes in two diverse mutant lines (low and high amylose mutants) showed higher expression of key genes of amylose biosynthesis (GBSSI and their isoforms) in the high amylose mutant line, in comparison to the parent. Higher expression of amylopectin biosynthesis (SBE) was observed in the low amylose mutant lines. An additional six candidate genes showed over-expression (BMY, SPA) and reduced-expression (SSIII, SBEI, SBEIII, ISA3) in the high amylose mutant line, indicating that other starch metabolic genes may also contribute to amylose biosynthesis.
CONCLUSION
In this study a set of 101 EMS-induced mutant lines (M4 generation) showing variation in amylose and resistant starch content in seed were produced. This population serves as useful germplasm or pre-breeding material for genome-wide study and improvement of starch-based processing and nutrition quality in wheat. It is also useful for the study of the genetic and molecular basis of amylose/resistant starch variation in wheat. Furthermore, gene expression analysis of 20 starch metabolic genes in the two diverse mutant lines (low and high amylose mutants) indicates that in addition to key genes, several other genes (such as phosphorylases, isoamylases, and pullulanases) may also be involved in contributing to amylose/amylopectin biosynthesis.
Topics: Amylose; Bread; Ethyl Methanesulfonate; Gene Expression Regulation, Plant; Mutagens; Mutation; Plant Proteins; Starch; Triticum
PubMed: 27716051
DOI: 10.1186/s12870-016-0896-z -
Molecules (Basel, Switzerland) Jan 2022The objective of this study was to obtain and characterize flours and starches from the avocado seeds of Hass and landrace cultivars. The morphological,...
The objective of this study was to obtain and characterize flours and starches from the avocado seeds of Hass and landrace cultivars. The morphological, physical-chemical, structural, thermal and rheological characteristics were evaluated. The flour yield of the Hass and landrace cultivars was 41.56 to 46.86% (/), while for starch, it was 35.47 to 39.57% (/) (cv. Hass and landrace, respectively). Scanning electron microscopy (SEM) revealed the presence of oval starch granules and other particles in flour, in contrast to flours, starches showed lower ash, proteins and lipids content. However, the amylose content was higher in starches (42.25-48.2%). Flours showed a higher gelatinization temperature ( = 73.17-73.62 °C), and their starches presented greater gelatinization enthalpy (∆ = 11.82-13.43 J/g). All samples showed a B-type diffraction pattern, and the crystallinity was higher in the flours. The rheological analysis (flow curves and viscoelastic tests) evidenced a pseudoplastic ( = 0.28-0.36) behavior in all samples analyzed, but the consistency index () was higher in starches. In general, the flours and starches from avocado seeds presented interesting proximal, thermal and functional properties for possible application in food systems, and these findings could contribute to the revaluation of this by-product.
Topics: Amylose; Flour; Hot Temperature; Persea; Rheology; Seeds; Starch; Thermodynamics; Viscosity
PubMed: 35164171
DOI: 10.3390/molecules27030910