Expression of bacterial starch-binding domains in Arabidopsis increases starch granule size

2006 ◽  
Vol 33 (3) ◽  
pp. 257 ◽  
Author(s):  
Crispin A. Howitt ◽  
Sadequr Rahman ◽  
Matthew K. Morell

Starch is a readily renewable resource that is very widely used for food and industrial purposes; however, greater variation in the functional properties of starch would further extend the use of this biodegradable polymer. Genetic engineering may provide a way to produce designer starches that have the desired properties. Starch-binding domains (SBD) from bacterial enzymes that catabolise starches have the ability to bind two helices of starch and thus have the potential to crosslink starch and / or to be used as anchors for other enzymes that can modify starch properties. In a first step towards novel modification of starch we have investigated the effect of expressing SBDs, singly and in tandem, in planta, and targeting them to the chloroplast in the model plant Arabidopsis thaliana (L.) Heynh. Transgenic plants that contained the SBD from the cyclomaltodextrin glucanotransferase (CGTase) of Thermoanaerobacterium thermosulfurigenes in the chloroplast were produced in both the wild type and the starch excess mutant (sex 1-1) backgrounds. Analysis of starch isolated from the chloroplasts of these lines revealed no significant changes in the amylose : amylopectin ratio, the chain-length distribution of debranched amylopectin or the gelatinisation temperature when compared to the parental line. However, significant changes were observed in the starch granule size with the plants expressing the construct having larger granules. The effect was more pronounced in the sex 1-1 background, and expression of two starch-binding domains linked in tandem had an even greater effect. Despite the starch granules being larger in lines expressing the starch-binding domain, no difference was seen in the starch content of the leaves when compared to parental lines. As the presence of the SBDs in the starch granule only altered granule size, and not other granule properties, they may provide an ideal anchor for targeting starch-modifying enzymes to the site of starch synthesis. This will allow the development of novel modifications of starch during synthesis.

2019 ◽  
Vol 71 (1) ◽  
pp. 105-115 ◽  
Author(s):  
Tansy Chia ◽  
Marcella Chirico ◽  
Rob King ◽  
Ricardo Ramirez-Gonzalez ◽  
Benedetta Saccomanno ◽  
...  

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.


2014 ◽  
Vol 5 (10) ◽  
pp. 2509-2515 ◽  
Author(s):  
Kai Lin Ek ◽  
Shujun Wang ◽  
Jennie Brand-Miller ◽  
Les Copeland

Starch from a low glycemic index (GI) potato cultivar (Carisma, shown in the ESEM image) was more resistant to hydrothermal treatment than other potato starches, but was not differentiated from the other starches by granule size distribution, amylose and P contents, and amylopectin chain length distribution.


2022 ◽  
Vol 52 (4) ◽  
Author(s):  
Wang Su ◽  
Guangji Ye ◽  
Yun Zhou ◽  
Jian Wang

ABSTRACT: Biosynthesis is the only source of potato starch which is an important raw material for food processing, modified starch and biomass energy. However, it is not clear about the evolution of starch synthesis with tuber development in potato. The present study evaluated the differences of starch synthesis and gelatinization properties of potato tubers with different starch content. Relative to cultivars of medium and low starch content, cultivars of high starch content showed significantly higher SBEII gene expression, AGPase and SSS enzyme activity, and total starch content after middle stage of starch accumulation, and had smaller average starch granule size during whole process of tuber development, and had higher pasting temperature before late stages of tuber growth, and had lower pasting temperature after middle stage of starch accumulation. Path analysis showed that, after middle stage of starch accumulation, effects on starch gelatinization of cultivars with high, medium and low starch content represented starch synthesis enzyme activity > starch accumulation > starch granule distribution > starch synthesis enzyme gene expression, starch synthesis enzyme gene expression > starch synthesis enzyme activity > starch accumulation > starch granule distribution, starch synthesis enzyme gene expression > starch granule distribution > starch synthesis enzyme activity > starch accumulation, respectively. In the study, phases existed in the starch biosynthesis of potato tuber, and the starch quality and its formation process were different among varieties with different starch content. The findings might contribute to starch application and potato industries.


Agronomy ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 297 ◽  
Author(s):  
Anon Janket ◽  
Nimitr Vorasoot ◽  
Banyong Toomsan ◽  
Wanwipa Kaewpradit ◽  
Poramate Banterng ◽  
...  

The information on genotypic responses to the seasonal variation in the starch content, starch yield, and starch quality of cassava is limited. The objective of this research was to investigate the seasonal variation of starch characteristics of three cassava genotypes grown under irrigation. The experiment was conducted at four planting dates (20 April, 30 June, 5 October, and 15 December 2015). Three cassava genotypes (CMR38-125-77, Kasetsart 50, and Rayong 11) were evaluated in a randomized complete block design with four replications and the plants were harvested at 12 months. The planting date contributed the largest portion of the total variation in the starch content, starch yield, and starch granule size. The amylose content variability was heavily influenced by genotype. Cassava planted on 5 October or 15 December had greater starch content, starch yield, and starch granule in most genotypes. This was likely due to a higher temperature and solar radiation during the 3–9 months post-planting. CMR38-125-77 showed a consistently high starch content, starch yield, and high amylose content for most planting dates except for the starch yield on 20 April, of which Rayong 11 was the best. These findings will be useful for choosing suitable cassava genotypes for different growing seasons and for facilitating breeding efforts for high starch-yielding and high-quality cassava starch in the future.


Agronomy ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 412 ◽  
Author(s):  
Anon Janket ◽  
Nimitr Vorasoot ◽  
Banyong Toomsan ◽  
Wanwipa Kaewpradit ◽  
Sanun Jogloy ◽  
...  

Although cassava can be planted throughout the year, its starch qualities may vary based on the date of planting. Seasonal variation on starch content, starch yield, starch granule size and amylose content of cassava cv. Rayong 9 grown under irrigated and rainfed conditions were studied for four planting dates in Thailand. A randomized complete block design with four replications was used in each planting. Planting dates consisted of hot-dry (20-Apr), early-rainy (30-Jun), late-rainy (5-Oct) and cool seasons (15-Dec). At final harvest, planting date accounted for the largest variations for starch yield (60.8%), starch granule size (38.2%), amylose content (50.5%) and ratio of amylose to amylopectin (53.7%), whereas starch content was affected more by water regime (52.1%). Supplemental irrigation did not significantly increase starch yield and other parameters for most planting dates, except for starch yield of the crop planted in the hot-dry season. This indicated that irrigation at the late-growth stages (during Sep to Mar) for the crop planted in the hot-dry season helped to increase starch yield; however, irrigation was unnecessary for other planting dates once cassava was established. The crops planted in the late-rainy and cool seasons had a greater starch content and starch yield than other planting dates for both irrigated and rainfed crops, whereas the crop planted in the hot-dry season had high starch yield for the irrigated crops only. In this study, the crops planted in the early-rainy season showed the worst performances for starch content and starch yield for both irrigated and rainfed crops. The data provided information on the responses of starch yield and its characteristics under irrigated and rainfed conditions at different planting dates, which can be useful for designing cultural practices with respect to water management and planting period in order to obtain optimum starch yield and qualities.


2018 ◽  
Author(s):  
Camille Vandromme ◽  
Corentin Spriet ◽  
David Dauvillée ◽  
Adeline Courseaux ◽  
Jean-Luc Putaux ◽  
...  

AbstractThe initiation of starch granule formation is still poorly understood. However, soluble starch synthase 4 (SS4) appears to be a major component of this process since it is required to synthetize the correct number of starch granules in the chloroplasts of Arabidopsis thaliana plants. A yeast-2-hybrid screen allowed the identification of several putative SS4 interacting partners. We identified the product of At4g32190 locus as a chloroplast-targeted PROTEIN INVOLVED IN STARCH INITIATION (named PII1). Arabidopsis mutants devoid of PII1 display an alteration of starch initiation process and accumulate, on average, one starch granule per plastid instead of the 5 to 7 granules found in plastids of wild-type plants. These granules are larger than in wild type and they remain flat and lenticular. pii1 mutants display wild-type growth rates and accumulate standard starch amounts. Moreover, starch characteristics, such as amylopectin chain length distribution, remain unchanged. Our results reveal the involvement of PII1 in starch priming process in Arabidopsis leaves through interaction with SS4.


2008 ◽  
Vol 7 (5) ◽  
pp. 872-880 ◽  
Author(s):  
Philippe Deschamps ◽  
Delphine Guillebeault ◽  
Jimi Devassine ◽  
David Dauvillée ◽  
Sophie Haebel ◽  
...  

ABSTRACT The nature of the cytoplasmic pathway of starch biosynthesis was investigated in the model heterotrophic dinoflagellate Crypthecodinium cohnii. The storage polysaccharide granules were shown to be composed of both amylose and amylopectin fractions with a chain length distribution and crystalline organization very similar to those of green algae and land plant starch. Preliminary characterization of the starch pathway demonstrated that C. cohnii contains multiple forms of soluble starch synthases and one major 110-kDa granule-bound starch synthase. All purified enzymes displayed a marked substrate preference for UDP-glucose. At variance with most other microorganisms, the accumulation of starch in the dinoflagellate occurs during early and mid-log phase, with little or no synthesis witnessed when approaching stationary phase. In order to establish a genetic system allowing the study of cytoplasmic starch metabolism in eukaryotes, we describe the isolation of marker mutations and the successful selection of random recombinant populations after homothallic crosses.


2007 ◽  
Vol 7 (2) ◽  
pp. 247-257 ◽  
Author(s):  
Charlotte Plancke ◽  
Christophe Colleoni ◽  
Philippe Deschamps ◽  
David Dauvillée ◽  
Yasunori Nakamura ◽  
...  

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.


2015 ◽  
Vol 112 (41) ◽  
pp. 12876-12881 ◽  
Author(s):  
Erez Eliyahu ◽  
Ido Rog ◽  
Dangoor Inbal ◽  
Avihai Danon

The regulatory mechanisms that use signals of low levels of reactive oxygen species (ROS) could be obscured by ROS produced under stress and thus are better investigated under homeostatic conditions. Previous studies showed that the chloroplastic atypical thioredoxin ACHT1 is oxidized by 2-Cys peroxiredoxin (2-Cys Prx) in Arabidopsis plants illuminated with growth light and in turn transmits a disulfide-based signal via yet unknown target proteins in a feedback regulation of photosynthesis. Here, we studied the role of a second chloroplastic paralog, ACHT4, in plants subjected to low light conditions. Likewise, ACHT4 reacted in planta with 2-Cys Prx, indicating that it is oxidized by a similar disulfide exchange reaction. ACHT4 further reacted uniquely with the small subunit (APS1) of ADP-glucose pyrophosphorylase (AGPase), the first committed enzyme of the starch synthesis pathway, suggesting that it transfers the disulfides it receives from 2-Cys Prx to APS1 and turns off AGPase. In accordance, ACHT4 participated in an oxidative signal that quenched AGPase activity during the diurnal transition from day to night, and also in an attenuating oxidative signal of AGPase in a dynamic response to small fluctuations in light intensity during the day. Increasing the level of expressed ACHT4 or of ACHT4ΔC, a C terminus-deleted form that does not react with APS1, correspondingly decreased or increased the level of reduced APS1 and decreased or increased transitory starch content. These findings imply that oxidative control mechanisms act in concert with reductive signals to fine tune starch synthesis during daily homeostatic conditions.


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