A carbohydrate-binding protein, B-GRANULE CONTENT 1, influences starch granule size distribution in a dose-dependent manner in polyploid wheat

Abstract In Triticeae endosperm (e.g. wheat and barley), starch granules have a bimodal size distribution (with A- and B-type granules) whereas in other grasses the endosperm contains starch granules with a unimodal size distribution. Here, we identify the gene, BGC1 (B-GRANULE CONTENT 1), responsible for B-type starch granule content in Aegilops and wheat. Orthologues of this gene are known to influence starch synthesis in diploids such as rice, Arabidopsis, and barley. However, using polyploid Triticeae species, we uncovered a more complex biological role for BGC1 in starch granule initiation: BGC1 represses the initiation of A-granules in early grain development but promotes the initiation of B-granules in mid grain development. We provide evidence that the influence of BGC1 on starch synthesis is dose dependent and show that three very different starch phenotypes are conditioned by the gene dose of BGC1 in polyploid wheat: normal bimodal starch granule morphology; A-granules with few or no B-granules; or polymorphous starch with few normal A- or B-granules. We conclude from this work that BGC1 participates in controlling B-type starch granule initiation in Triticeae endosperm and that its precise effect on granule size and number varies with gene dose and stage of development.

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The A to B of starch granule formation in wheat endosperm

Journal of Experimental Botany ◽

10.1093/jxb/erz414 ◽

2019 ◽

Vol 71 (1) ◽

pp. 1-3

Author(s):

James R Lloyd

Keyword(s):

Size Distribution ◽

Starch Granule ◽

Granule Size ◽

Carbohydrate Binding ◽

Dependent Manner ◽

Granule Formation ◽

Polyploid Wheat ◽

Carbohydrate Binding Protein ◽

Experimental Botany ◽

Dose Dependent

This article comments on: Chia T, Chirico M, King R et al. 2019. A carbohydrate-binding protein, B-granule content 1 influences starch granule-size distribution in a dose dependent manner in polyploid wheat. Journal of Experimental Botany 70, 105–115.

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Starch granule size distribution in wheat grain in relation to phosphorus fertilization

The Journal of Agricultural Science ◽

10.1017/s0021859611000475 ◽

2011 ◽

Vol 150 (1) ◽

pp. 45-52 ◽

Cited By ~ 14

Author(s):

Y. NI ◽

Z. WANG ◽

Y. YIN ◽

W. LI ◽

S. YAN ◽

...

Keyword(s):

Size Distribution ◽

Starch Granule ◽

Amylose Content ◽

Granule Size ◽

High Yield ◽

Phosphorus Fertilization ◽

Equivalent Diameter ◽

Starch Granules ◽

P Fertilization ◽

Volume Proportion

SUMMARYStarch granule size distribution of wheat is an important characteristic that can affect its chemical composition and functionality. Phosphorus (P) fertilization has been studied extensively; however, little is known about its impact on starch granule size distribution in wheat. In the present study, two high-yield winter wheat cultivars were grown under different P fertilization conditions to evaluate its effect on starch granule size distribution and starch components in wheat grains at maturity. P fertilization resulted in a significant increase in the proportions (both by volume and by surface area) of B-type (<9·9 μm equivalent diameter (e.d.)) starch granules, with a reduction in those of A-type (>9·9 μm e.d.) starch granules. The P fertilization also increased starch content, amylose content and amylopectin content at maturity. However, P fertilization conditions significantly reduced the ratio of amylose to amylopectin, which showed a significant positive relationship with the volume proportion of granules 22·8–42·8 μm e.d. but was negatively related to the volume proportion of granules 2·8–9·9 μm e.d.

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A carbohydrate-binding protein, FLOURY ENDOSPERM 6 influences the initiation of A- and B-type starch granules in wheat

10.1101/643759 ◽

2019 ◽

Author(s):

Tansy Chia ◽

Marcella Chirico ◽

Rob King ◽

Ricardo Ramirez-Gonzalez ◽

Benedetta Saccomanno ◽

...

Keyword(s):

Starch Granule ◽

Carbohydrate Binding ◽

Starch Granules ◽

Grain Development ◽

Triple Mutant ◽

Floury Endosperm ◽

Group 4 ◽

Trait Locus ◽

B Granules ◽

Stimulation Of

AbstractPreviously, we identified a quantitative trait locus on the group 4 chromosomes of Aegilops and bread wheat that controls B-type starch-granule content. Here, we identify a candidate gene by fine-mapping in Aegilops and confirm its function using wheat TILLING mutants. This gene is orthologous to the FLOURY ENDOSPERM 6 (FLO6) gene of rice and barley and the PTST2 gene of Arabidopsis. In Triticeae endosperm, reduction in the gene dose of functional FLO6 alleles results in reduction, or loss, of B-granules. This is due to repression of granule initiation in late-grain development, but has no deleterious impact on the synthesis of A-granules. The complete absence of functional FLO6, however, results in reduced numbers of normal A-type and B-type granules and the production of highly-abnormal granules that vary in size and shape. This polymorphous starch seen in a wheat flo6 triple mutant is similar to that observed in the barley mutant Franubet. Analysis of Franubet (fractured Nubet) starch suggests that the mutant A-granules are not fractured but compound, due to stimulation of granule initiation in plastids during early-grain development. Thus, in different situations in Triticeae, FLO6 either stimulates or represses granule initiation.

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Starch granule size distribution from twelve wheat cultivars in east China’s Huaibei region

Canadian Journal of Plant Science ◽

10.1139/cjps-2015-0048 ◽

2016 ◽

Vol 96 (2) ◽

pp. 176-182 ◽

Cited By ~ 4

Author(s):

Wenyang Li ◽

Suhui Yan ◽

Xiaqing Shi ◽

Congyu Zhang ◽

Qingqin Shao ◽

...

Keyword(s):

Size Distribution ◽

Starch Granule ◽

Amylose Content ◽

Granule Size ◽

Volume Distribution ◽

Starch Granules ◽

Wheat Cultivars ◽

Volume Percentage ◽

Area Distribution ◽

Two Populations

The granule size distribution of starch strongly influences its physicochemical properties and the functionality of wheat. Twelve wheat cultivars grown in east China’s Huanghuai region were used for investigating the granule size distribution, amylose content, and their interrelationship. The results showed that the volume distribution of starch granules show the typical bimodal with peak values in the ranges of 4.44–5.36 µm and 21.7–23.82 µm, respectively. Surface area distribution of granules was also bimodal with peak values in the ranges of 2.53–3.06 µm and 19.8–21.7 µm, respectively. The limits between the two populations both occurred at 10 µm. A typical population of number distribution of granules with peak values in the range of 0.52–0.67 µm. Proportions of granules <2.6 µm, 2.6–10 µm, and 10–40 µm were in the range of 10.06–13.63%, 28.54–41.6%, and 45.4–61.3% of total volume, respectively. Proportions of granules <10 µm were in the range of 99.9% of the total number. The amylose content was significant and negatively correlated to volume percentage of granule <10 µm, and significant and positively correlated to the volume percentage of granule 22–40 µm.

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Genetics of starch granule size distribution in tetraploid and hexaploid wheats

Australian Journal of Agricultural Research ◽

10.1071/ar03016 ◽

2003 ◽

Vol 54 (7) ◽

pp. 637 ◽

Cited By ~ 15

Author(s):

F. L. Stoddard

Keyword(s):

Size Distribution ◽

Starch Granule ◽

Triticum Turgidum ◽

Tetraploid Wheat ◽

Granule Size ◽

Cytoplasmic Effects ◽

Additive Gene ◽

The One ◽

B Granules ◽

Granule Diameter

Wheat endosperm starch is deposited in large, A-type granules and smaller B-type and C-type granules. The quantitative genetics of starch granule size distribution was investigated in 2 ways. Complete diallel crosses, with 5 parents each, were prepared in tetraploid wheat, Triticum turgidum, and hexaploid wheat, Triticum aestivum. Parent and F1 plants were grown in controlled environment growth chambers with 18�C days and 13�C nights to provide parent and F2 grains from uniform conditions. In the same conditions, the basic generations of parent, F1, F2, and backcross of 6 other individual crosses were grown and F1 and backcross grains were freshly generated on these plants. Starch granule size distribution was determined in parent and F2 grains in the diallels and all possible generations in the other crosses. Granules of <10 μm diameter were considered 'B granules' (thus including C granules), and B-granule content was expressed as a percentage of total starch volume. The modal A-granule diameter was also determined.B-granule content varied widely in both species, whereas modal A-granule diameter was much more variable in tetraploids than in hexaploids. Additive gene action was more important than dominance in determining B-granule content in both species and A-granule diameter in tetraploids, whereas dominance was more important for A-granule diameter in hexaploids. Dominance acted to increase or to decrease B-granule content, depending on the cross. According to variance–covariance analysis, the line with the most dominant alleles in the hexaploids was the one lowest in B granules, but in the tetraploids it was the one highest in B granules. Digenic interactions affected B-granule content and A-granule diameter in all of the analyses of the basic generations, and nucleocytoplasmic interactions affected these traits in most of the crosses. Diallel analyses of the F2 generations, in contrast, showed a limited importance of epistasis. Cytoplasmic effects made small but significant contributions to the variation in B-granule content in some of the crosses. Variation in B-granule content and A-granule diameter appeared to be affected by different gene actions and were therefore likely to be susceptible to independent manipulations in a breeding program.

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Starch granule size distribution in wheat grain in relation to shading after anthesis

The Journal of Agricultural Science ◽

10.1017/s0021859609990554 ◽

2009 ◽

Vol 148 (2) ◽

pp. 183-189 ◽

Cited By ~ 16

Author(s):

W. LI ◽

S. YAN ◽

Y. YIN ◽

Z. WANG

Keyword(s):

Light Intensity ◽

Grain Yield ◽

Size Distribution ◽

Starch Granule ◽

Grain Filling ◽

Granule Size ◽

Wheat Starch ◽

High Yield ◽

Starch Accumulation ◽

Starch Granules

SUMMARYGranule size distribution of wheat starch is an important characteristic that may affect the functionality of wheat products. Light intensity is one of the main factors affecting grain yield and quality. Two high-yield winter wheat cultivars were grown under shade to evaluate the effect of low light intensity after anthesis on starch granule size distribution and starch components in wheat grains at maturity. Shading caused a marked drop in both grain yield and starch yield and led to a significant reduction in the proportion (both by volume and by surface area) of B-type starch granules (⩽9·9 μm), with an increase in those of A-type starch granules (>9·9 μm). This would suggest that the production of B-type starch granules was more sensitive to shading than that of A-type starch granules. It was also found that the proportion by volume of A-type starch granules was significantly increased and that of B-type starch granules was significantly decreased by shading at different grain filling stages, especially at middle and late grain-filling stages. However, shading had little effect on the proportional number of B-type starch granules. The present results suggested that, under dim light conditions, the limited substrate for starch accumulation was mainly partitioned towards hypertrophy (larger granules) not hyperplasia (more) of starch granules.

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Brewing trials with spring and winter barley varieties

Czech Journal of Food Sciences ◽

10.17221/145/2010-cjfs ◽

2012 ◽

Vol 30 (No. 1) ◽

pp. 27-34

Author(s):

A. Mikyška ◽

V. Psota ◽

M. Hrabák

Keyword(s):

Size Distribution ◽

Starch Granule ◽

Granule Size ◽

Starch Granules ◽

Spent Grains ◽

Significant Difference ◽

Brewing Process ◽

Decoction Process ◽

Beer Production

The effects of a set of barley varieties on the brewing process and quality of beer production intermediaries were studied in trial brews (40 l) prepared using the two-mash decoction process. The varieties included in the trial were selected based on the starch granule size distribution determined previously. A significant effect of the varieties on the saccharification time of both mashes was determined. The highest saccharification rate in brews was achieved with the variety Jersey; the saccharification time of the 1<sup>st</sup> and 2<sup>nd</sup> mash with the variety Tiffany was markedly longer. The varieties with a greater fraction of large starch granules (Tiffany and Luxor) exhibited a higher haze with sweet wort as well as hopped wort compared to the varieties with a low fraction of large starch granules (Jersey and Tolar). The effect on the lautering time was not demonstrated. Pronounced varietal differences were determined in the extract balance of the brewing process. The varieties Tiffany andLuxor exhibited significantly lower extract yields. The malts from these varieties had lower laboratory extracts and higher extract losses in spent grains. The effect of the variety on the sacharide composition in hopped wort was confirmed. The proportion of fermentable saccharides in hopped wort extract rose from the variety Tiffany (66.9%) to the varietyJersey (83.6%). A significant difference in the final attenuation was also determined (76% in beers prepared from the varieties Tiffany andLuxor compared to 81.5% from theJersey variety).  

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