scholarly journals Triple null mutations in starch synthase SSIIa gene homoeologs lead to high amylose and resistant starch in hexaploid wheat

2020 ◽  
Author(s):  
Adam Schoen ◽  
Anupama Joshi ◽  
Vijay K Tiwari ◽  
Bikram S. Gill ◽  
Nidhi Rawat

Abstract Background: Lack of nutritionally appropriate foods is one of the leading causes of obesity in the US and worldwide. Wheat (Triticum aestivum) provides 20% of the calories consumed daily across the globe. The nutrients in the wheat grain come primarily from the starch composed of amylose and amylopectin. Resistant starch content, which is known to have significant human health benefits, can be increased by modifying starch synthesis pathways. Starch synthase enzyme SSIIa, also known as starch granule protein isoform-1 (SGP-1), is integral to the biosynthesis of the branched and readily digestible glucose polymer amylopectin. The goal of this work was to develop a triple null mutant genotype for SSIIa locus in the elite hard red winter wheat variety ‘Jagger’ and evaluate the effect of the knock-out mutations on resistant starch content in grains with respect to wild type. Results: Knock-out mutations in SSIIa in the three genomes of wheat variety ‘Jagger’ were identified using TILLING. Subsequently, these loss-of function mutations on A, B, and D genomes were combined by crossing to generate a triple knockout mutant genotype Jag-ssiia-∆ABD. The Jag-ssiia-∆ABD had an amylose content of 35.70% compared to 31.15% in Jagger, leading to ~118% increase in resistant starch in the Jag-ssiia-∆ABD genotype of Jagger wheat. The single individual genome mutations also had various effects on starch composition. Conclusions: Our full null Jag-ssiia-∆ABD mutant showed a significant increase in RS without the shriveled grain phenotype seen in other ssiia knockouts in elite wheat cultivars. Moreover, this study shows the potential for developing nutritionally improved foods in a non-GM approach. Since all the mutants have been developed in an elite wheat cultivar, their adoption in production and supply will be feasible in future.

2021 ◽  
Author(s):  
Adam Schoen ◽  
Anupama Joshi ◽  
Vijay K Tiwari ◽  
Bikram S. Gill ◽  
Nidhi Rawat

Abstract Background: Lack of nutritionally appropriate foods is one of the leading causes of obesity in the US and worldwide. Wheat (Triticum aestivum) provides 20% of the calories consumed daily across the globe. The nutrients in the wheat grain come primarily from the starch composed of amylose and amylopectin. Resistant starch content, which is known to have significant human health benefits, can be increased by modifying starch synthesis pathways. Starch synthase enzyme SSIIa, also known as starch granule protein isoform-1 (SGP-1), is integral to the biosynthesis of the branched and readily digestible glucose polymer amylopectin. The goal of this work was to develop a triple null mutant genotype for SSIIa locus in the elite hard red winter wheat variety ‘Jagger’ and evaluate the effect of the knock-out mutations on resistant starch content in grains with respect to wild type. Results: Knock-out mutations in SSIIa in the three genomes of wheat variety ‘Jagger’ were identified using TILLING. Subsequently, these loss-of function mutations on A, B, and D genomes were combined by crossing to generate a triple knockout mutant genotype Jag-ssiia-∆ABD. The Jag-ssiia-∆ABD had an amylose content of 35.70% compared to 31.15% in Jagger, leading to ~118% increase in resistant starch in the Jag-ssiia-∆ABD genotype of Jagger wheat. The single individual genome mutations also had various effects on starch composition. Conclusions: Our full null Jag-ssiia-∆ABD mutant showed a significant increase in RS without the shriveled grain phenotype seen in other ssiia knockouts in elite wheat cultivars. Moreover, this study shows the potential for developing nutritionally improved foods in a non-GM approach. Since all the mutants have been developed in an elite wheat cultivar, their adoption in production and supply will be feasible in future.


2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Adam Schoen ◽  
Anupama Joshi ◽  
Vijay Tiwari ◽  
Bikram S. Gill ◽  
Nidhi Rawat

Abstract Background Lack of nutritionally appropriate foods is one of the leading causes of obesity in the US and worldwide. Wheat (Triticum aestivum) provides 20% of the calories consumed daily across the globe. The nutrients in the wheat grain come primarily from the starch composed of amylose and amylopectin. Resistant starch content, which is known to have significant human health benefits, can be increased by modifying starch synthesis pathways. Starch synthase enzyme SSIIa, also known as starch granule protein isoform-1 (SGP-1), is integral to the biosynthesis of the branched and readily digestible glucose polymer amylopectin. The goal of this work was to develop a triple null mutant genotype for SSIIa locus in the elite hard red winter wheat variety ‘Jagger’ and evaluate the effect of the knock-out mutations on resistant starch content in grains with respect to wild type. Results Knock-out mutations in SSIIa in the three genomes of wheat variety ‘Jagger’ were identified using TILLING. Subsequently, these loss-of function mutations on A, B, and D genomes were combined by crossing to generate a triple knockout mutant genotype Jag-ssiia-∆ABD. The Jag-ssiia-∆ABD had an amylose content of 35.70% compared to 31.15% in Jagger, leading to ~ 118% increase in resistant starch in the Jag-ssiia-∆ABD genotype of Jagger wheat. The single individual genome mutations also had various effects on starch composition. Conclusions Our full null Jag-ssiia-∆ABD mutant showed a significant increase in RS without the shriveled grain phenotype seen in other ssiia knockouts in elite wheat cultivars. Moreover, this study shows the potential for developing nutritionally improved foods in a non-GM approach. Since all the mutants have been developed in an elite wheat cultivar, their adoption in production and supply will be feasible in future.


2020 ◽  
Author(s):  
Adam Schoen ◽  
Anupama Joshi ◽  
Vijay K Tiwari ◽  
Bikram S. Gill ◽  
Nidhi Rawat

Abstract Background: Lack of nutritionally appropriate foods is one of the leading causes of obesity in the US and worldwide. Wheat (Triticum aestivum) provides 20% of the calories consumed daily across the globe. The nutrients in the wheat grain come primarily from the starch composed of amylose and amylopectin. Resistant starch content, which is known to have significant human health benefits, can be increased by modifying starch synthesis pathways. Starch synthase enzyme SSIIa, also known as starch granule protein isoform-1 (SGP-1), is integral to the biosynthesis of the branched and readily digestible glucose polymer amylopectin. The goal of this work was to develop a triple null mutant genotype for SSIIa locus in the elite hard red winter wheat variety ‘Jagger’ and evaluate the effect of the knock-out mutations on resistant starch content in grains with respect to wild type. Results: Knock-out mutations in SSIIa in the three genomes of wheat variety ‘Jagger’ were identified using TILLING. Subsequently, these loss-of function mutations on A, B, and D genomes were combined by crossing to generate a triple knockout mutant genotype Jag-ssiia-∆ABD. The Jag-ssiia-∆ABD had an amylose content of 35.70% compared to 31.15% in Jagger, leading to ~118% increase in resistant starch in the Jag-ssiia-∆ABD genotype of Jagger wheat. The single individual genome mutations also had various effects on starch composition. Conclusions: Our full null Jag-ssiia-∆ABD mutant showed a significant increase in RS without the shriveled grain phenotype seen in other ssiia knockouts in elite wheat cultivars. Moreover, this study shows the potential for developing nutritionally improved foods in a non-GM approach. Since all the mutants have been developed in an elite wheat cultivar, their adoption in production and supply will be feasible in future.


2020 ◽  
Author(s):  
Adam Schoen ◽  
Anupama Joshi ◽  
Vijay K Tiwari ◽  
Bikram S. Gill ◽  
Nidhi Rawat

Abstract Background: Lack of nutritionally appropriate foods is one of the leading causes of obesity in the US and worldwide. Wheat (Triticum aestivum) provides 20% of the calories consumed daily across the globe. The nutrients in the wheat grain come primarily from the starch composed of amylose and amylopectin. Resistant starch content, which is known to have significant human health benefits, can be increased by modifying starch synthesis pathways. Starch synthase enzyme SSIIa, also known as starch granule protein isoform-1 (SGP-1), is integral to the biosynthesis of the branched and readily digestible glucose polymer amylopectin. The goal of this work was to develop a triple null mutant genotype for SSIIa locus in the elite hard red winter wheat variety ‘Jagger’ and evaluate the effect of the knock-out mutations on resistant starch content in grains with respect to wild type. Results: Knock-out mutations in SSIIa in the three genomes of wheat variety ‘Jagger’ were identified using TILLING. Subsequently, these loss-of function mutations on A, B, and D genomes were combined by crossing to generate a triple knockout mutant genotype Jag-ssiia-∆ABD. The Jag-ssiia-∆ABD had an amylose content of 35.70% compared to 31.15% in Jagger, leading to ~118% increase in resistant starch in the Jag-ssiia-∆ABD genotype of Jagger wheat. The single individual genome mutations also had various effects on starch composition. Conclusions: Our full null Jag-ssiia-∆ABD mutant showed a significant increase in RS without the shriveled grain phenotype seen in other ssiia knockouts in elite wheat cultivars. Moreover, this study shows the potential for developing nutritionally improved foods in a non-GM approach. Since all the mutants have been developed in an elite wheat cultivar, their adoption in production and supply will be feasible in future.


2020 ◽  
Author(s):  
Adam Schoen ◽  
Anupama Joshi ◽  
Vijay K Tiwari ◽  
Bikram S. Gill ◽  
Nidhi Rawat

Abstract Background Lack of nutritionally appropriate foods is one of the leading causes of obesity in the US and worldwide. Wheat (Triticum aestivum) provides 20% of the calories consumed daily across the globe. The nutrients in the wheat kernel come primarily from the starch composed of amylose and amylopectin. Resistant starch content, which is known to have significant human health benefits, can be increased by modifying starch synthesis pathways. Starch synthase enzyme SSIIa, also known as starch granule proteins isoform-1 (SGP-1), is integral to the biosynthesis of the branched and readily digestible glucose polymer amylopectin. In this study, a triple knockout mutant genotype (ssiia ∆ ABD) at the SSIIa locus was developed in elite hard red winter wheat variety ‘Jagger’. Results Knock-out mutations in SSIIa in the three genomes of wheat variety ‘Jagger’ were identified using TILLING. Subsequently, these loss-of function mutations on A, B, and D genomes were genetically combined to generate a triple knockout mutant genotype ssiia ∆ ABD. The ssiia ∆ ABD had an amylose content of 35.70% compared to 31.15% in Jagger, leading to ~ 118% increase in resistant starch in the ssiia ∆ ABD genotype of Jagger wheat. The single individual genome mutations also had various effects on starch composition. Conclusions This marks the first time a full null ssiia knockout has been achieved in a single elite cultivar background and shows the potential for developing nutritionally superior foods in a non-GM approach. Since all the mutants have been developed in an elite wheat cultivar, their adoption in production and supply will be easy.


1990 ◽  
Vol 17 (4) ◽  
pp. 431 ◽  
Author(s):  
CY Caley ◽  
CM Duffus ◽  
B Jeffcoat

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.


2009 ◽  
Vol 27 (Special Issue 1) ◽  
pp. S120-S124 ◽  
Author(s):  
R. Dostálová ◽  
J. Horáček ◽  
I. Hasalová ◽  
R. Trojan

Total starch (TS), amylose and resistant starch (RS) were determined in the sets of smooth pea and wrinkled pea varieties in the years 2006–2008. Starch content of smooth peas varied in the range 53.61–57.23%. Average amylose content was 27.8%. Resistant starch content varied from 2.07% to 6.31%. Content of starch at wrinkled pea varied from 26.57% to 32.55%. Average amylose content was 76.82% of total starch. Content of total starch increases continually during seed development. The dependence of total starch on determined dry mass in harvested sample can be defined by equation &gamma; = 1.2427 × –6.5611, by determination coefficient <I>R</I><sup>2</sup> = 0.8936 and highly significant correlation coefficient <I>r</I> = 0.945. Total starch content in dry seed reached final average value 29.56%. In garden pea, the level of maturity (by tenderometric measurement) and dry matter were determined. Resistant starch content of 11 garden pea cultivars was studied in three different terms of technological harvest.


2016 ◽  
Vol 113 (39) ◽  
pp. 10842-10847 ◽  
Author(s):  
Zhiyong Zhang ◽  
Xixi Zheng ◽  
Jun Yang ◽  
Joachim Messing ◽  
Yongrui Wu

The maize endosperm-specific transcription factors opaque2 (O2) and prolamine-box binding factor (PBF) regulate storage protein zein genes. We show that they also control starch synthesis. The starch content in the PbfRNAi and o2 mutants was reduced by ∼5% and 11%, respectively, compared with normal genotypes. In the double-mutant PbfRNAi;o2, starch was decreased by 25%. Transcriptome analysis reveals that >1,000 genes were affected in each of the two mutants and in the double mutant; these genes were mainly enriched in sugar and protein metabolism. Pyruvate orthophosphate dikinase 1 and 2 (PPDKs) and starch synthase III (SSIII) are critical components in the starch biosynthetic enzyme complex. The expression of PPDK1, PPDK2, and SSIII and their protein levels are further reduced in the double mutants as compared with the single mutants. When the promoters of these genes were analyzed, we found a prolamine box and an O2 box that can be additively transactivated by PBF and O2. Starch synthase IIa (SSIIa, encoding another starch synthase for amylopectin) and starch branching enzyme 1 (SBEI, encoding one of the two main starch branching enzymes) are not directly regulated by PBF and O2, but their protein levels are significantly decreased in the o2 mutant and are further decreased in the double mutant, indicating that o2 and PbfRNAi may affect the levels of some other transcription factor(s) or mRNA regulatory factor(s) that in turn would affect the transcript and protein levels of SSIIa and SBEI. These findings show that three important traits—nutritional quality, calories, and yield—are linked through the same transcription factors.


Foods ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 1316
Author(s):  
Federica Taddei ◽  
Elena Galassi ◽  
Francesca Nocente ◽  
Laura Gazza

The demand for gluten-free products, including pasta, is increasing and rice pasta accounts for the largest share of this market. Usually, the production of rice pasta requires additives or specific technological processes able to improve its texture, cooking quality, and sensory properties. In this work, two rice cultivars, with different amylose content, were subjected to parboiling, micronization, and flour air fractionation to obtain brown rice pasta, without any supplement but rice itself. In particular, two types of pasta (spaghetti shape) were produced, one from 100% micronized wholemeal, and the other from refined rice flour replaced with 15% of the air-fractionated fine fraction. Regardless of the cultivar, pasta from wholemeal micronized flour showed higher protein and fiber content than refined flour enriched with fine fraction, whereas no differences were revealed in resistant starch and antioxidant capacity. Pasta from the high amylose content genotype showed the highest resistant starch content and the lowest predicted glycemic index along with sensorial characteristics as good as durum semolina pasta in fine fraction enriched pasta. Besides the technological processes, pasta quality was affected the most by the genotype, since pasta obtained from high amylose cv Gladio resulted in the best in terms of technological and sensory quality.


2020 ◽  
Author(s):  
Hui You ◽  
Ouling Zhang ◽  
Xu Liang ◽  
Cheng Liang ◽  
Yongjun Chen ◽  
...  

Abstract BackgroundResistant Starch (RS) is a functional starch that has functions of regulating diabetes, hypertension and obesity. The effects of most starch synthesis-related genes (SSRGs) on RS content and their relationships are largely unknown. ResultsIn current study, ninety-nine lines from a recombinant inbred line were selected to investigate the effects of SSRGs on the RS content in different process status. Results revealed that RS content decreased dramatically after cooking, but it did not increase significantly after cooling for 7 days. And RS was closely related to many indexes of physicochemical properties, but was not correlated with granule size. Waxy (Wx) played an important role in controlling RS content and Wxa could elevate RS content in raw milled rice, cooked rice and retrograded rice. Soluble starch synthase IIa (SSIIa) had an impact on RS2, and RS2 content of indica SSIIa were significantly higher than that of japonica SSIIa (SSIIaj). Moreover, interaction of Wx and SSIIa was responsible for variations of RS content in three sample types, RS2 and volume proportion of different size starch granules. ConclusionsWx and SSIIa together significantly regulate different types content of RS in rice, but SSIIa only affects RS2. Wxa-SSIIaj is favorable to forming large-diameter starch granules.


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