Studies on Starches of High Amylose Content. Part 17. A Review of Current Concepts

The sensory and functional properties of rice are predominantly associated with its amylose content. Granule-bound starch synthase (GBSS) encoded by the Waxy (Wx) gene determines the synthesis of amylose, while starch branching enzymes encoded by Sbe genes are involved in the formation of amylopectin. Some studies have demonstrated that Wx gene is the major controller of amylose content but there are one or more modifying genes affecting the amylose content. Three markers, microsatellite, Single – nucleotide – polymorphism (G/T SNP) in Wx gene and Single – nucleotide – polymorphism (T/C SNP) in Sbe1 gene, were tested for their association with amylose content using sixty-nine rice accessions from twenty countries. Of the three markers, two markers in Wx gene are significantly associated with amylose content. The combination of two markers in Wx gene (haplotypes) explained 83.8% of the variation in amylose content and discriminated the three market classes of glutinous, low, intermediate and high amylose content of rice from each other. And T/C SNP in Sbe1 locus was not a suitable marker for amylose content. Keywords: marker, amylose content, Waxy gene.

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Production of very-high-amylose cassava by post-transcriptional silencing of branching enzyme genes

10.1101/477414 ◽

2018 ◽

Author(s):

Wenzhi Zhou ◽

Shanshan Zhao ◽

Shutao He ◽

Qiuxiang Ma ◽

Xinlu Lu ◽

...

Keyword(s):

Amylose Content ◽

Length Distribution ◽

Constitutive Expression ◽

Raw Material ◽

Distribution Analysis ◽

Starch Granules ◽

Storage Roots ◽

Chain Length Distribution ◽

Transgenic Cassava ◽

High Amylose

AbstractHigh amylose starch, a desired raw material in the starch industry, can be produced by plants deficient in the function of branching enzymes (BEs). Here we report the production of transgenic cassava plants with starches containing up to 50% amylose due to the constitutive expression of hair-pin dsRNAs targeting the BE1 or BE2 genes. A significant decrease in BE transcripts was confirmed in these transgenic plants by quantitative real-time RT-PCR. The absence of BE1 protein in the BE1-RNAi plant lines (BE1i) and a dramatically lower level of BE2 protein in the BE2-RNAi plant lines (BE2i) were further confirmed by Western blot assays. All transgenic plant lines were grown up in the field, but with reduced biomass production of the above-ground parts and storage roots compared to wild type (WT). Considerably high amylose content in the storage roots of BE2i plant lines was achieved, though not in BE1i plant lines. Storage starch granules of BE1i and BE2i plants had similar morphology as WT, however, the size of BE1i starch granules were bigger than that of WT. Comparisons of amylograms and thermograms of all three sources of storage starches revealed dramatic changes to the pasting properties and a higher melting temperature for BE2i starches. Glucan chain length distribution analysis showed a slight increase in chains of DP>36 in BE1i lines and a dramatic increase in glucan chains between DP 10-20 and DP>40 in BE2i lines, compared to that of WT starch. Furthermore, BE2i starches displayed a B-type X-ray diffraction pattern instead of the A-type pattern found in BE1i and WT starches. Therefore, cassava BE1 and BE2 function differently in storage root starch biosynthesis; silencing of cassava BE1 or BE2 caused various changes to starch physico-chemical properties and amylopectin structure. We also report that remarkably high amylose content in cassava starch has been first obtained in transgenic cassava by silencing of BE2 expression, thus showing a high potential for future industrial utilization.

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Study of antioxidant activity and anti-cholesterol content on red yeast rice with substrates variation (rice, corn and dried cassava)

Biofarmasi Journal of Natural Product Biochemistry ◽

10.13057/biofar/f090202 ◽

2011 ◽

Vol 9 (2) ◽

pp. 38-44

Author(s):

HADI WIYOTO ◽

M. A.M. ANDRIANI ◽

NUR HER RIYADI PARNANTO

Keyword(s):

Antioxidant Activity ◽

Amylose Content ◽

Cholesterol Content ◽

The Other ◽

Red Yeast Rice ◽

Red Yeast ◽

Randomized Design ◽

Completely Randomized Design ◽

Level Of Significance ◽

High Amylose

Wiyoto H, Andriani MAM, Parnanto NHR. 2011. Study of antioxidant activity and anti-cholesterol content on red yeast rice with substrates variation (rice, corn and dried cassava). Biofarmasi 9: 38-44. Red yeast rice is one of fermented rice product by Monascus purpureus. Traditionally, the substrate used to produce red yeast rice is rice. Usually, the rice with high amylose content is proper to produce red yeast rice than low amylose. The other substrates that be used to produce red yeast rice are corn and dried cassava. The purposes of this research were to determine the effect of substrates variation (rice, corn and dried cassava) on antioxidant activity and anti-cholesterol content in red yeast rice, and to determine the substrate(s) that produce the highest antioxidant activity and anticholesterol content. The design of this research was a Completely Randomized Design with one factor, i.e. the kind of substrates: rice, corn and dried cassava, with three replications. Then, the data were analyzed with ANOVA at a level of significance Î±=0.05, and continued with DMRT at the same level. This results showed that the effect of substrates kind to antioxidant activity and anti-cholesterol content on red yeast rice. The rice substrate had higher antioxidant activity and anti-cholesterol content than corn and dried cassava substrates. The antioxidant activity and the anti-cholesterol content on red yeast rice from rice substrate were 45.6100% and 0.026600%, respectively. The antioxidant activity and the anti-cholesterol content on red yeast rice from corn substrate were 44.0500% and 0.022833%, respectively, while the antioxidant activity and the anti-cholesterol content on red yeast rice from dried cassava substrate were 42.8333% and 0.013200%, respectively.

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