A mutation in Waxy gene affects amylose content, starch granules and kernel characteristics of barley ( Hordeum vulgare )

2019 ◽  
Vol 138 (5) ◽  
pp. 513-523 ◽  
Author(s):  
Qiao Li ◽  
Zhifen Pan ◽  
Juan Liu ◽  
Guangbing Deng ◽  
Hai Long ◽  
...  
Author(s):  
Dương Thanh Thủy ◽  
Taiichiro Ookawa

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.


2018 ◽  
Author(s):  
Wenzhi Zhou ◽  
Shanshan Zhao ◽  
Shutao He ◽  
Qiuxiang Ma ◽  
Xinlu Lu ◽  
...  

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.


Proceedings ◽  
2020 ◽  
Vol 36 (1) ◽  
pp. 140 ◽  
Author(s):  
Changquan Zhang ◽  
Jihui Zhu ◽  
Shengjie Chen ◽  
Qiaoquan Liu

In rice endosperms, the Waxy (Wx) gene is important for amylose synthesis, and various Wx alleles control the amylose content and affect the taste of cooked rice. Herein, we report the cloning of the ancestral allele Wxlv of the Wx locus, which affects the mouthfeel of rice grains by modulating the size of amylose molecules. Using evolutionary analysis, we demonstrated that Wxlv originated directly from wild rice, and the three major Wx alleles in cultivated rice (Wxb, Wxa, and Wxin) differentiated after the substitution of one base pair at the functional sites. These data indicate that the Wxlv allele played an important role in artificial selection and domestication. The findings also shed light on the evolution of various Wx alleles, which have greatly contributed to improving the eating and cooking quality of rice.


2007 ◽  
Vol 90 (6) ◽  
pp. 1628-1634 ◽  
Author(s):  
Tatsuya Morita ◽  
Yusuke Ito ◽  
Ian Lewis Brown ◽  
Ryuichi Ando ◽  
Shuhachi Kiriyama

Abstract Digestibility of maize starch granules with different amylose content (AL-0, 22, 54, 68, 80, or 90) was investigated. Measurement of the in vivo resistant starch (RS) content of the starches was performed using surgically prepared ileorectostomized rats. The rats were fed a purified diet containing one of the starches at 652.5 g/kg diet. The in vivo RS content was determined based on the fecal starch excretion. The dietary fiber (DF) value increased as a function of the amylose content in the starch and showed a positive linear correlation with the gelatinization temperature of the granules. In contrast, the in vitro RS content was likely to depend on both the surface area and amylose contents of the starch granules. The maximum in vitro RS content was obtained with AL-68 (54.4). In vivo RS content showed a significant correlation with the amount of in vitro RS but not in respect to the DF detected. The in vivo RS content of AL-68 (43.4) was higher than that found in AL-90 (37.8). A profound gap was observed for AL-54 between the amount of DF (6.4) and RS (in vitro = 46.6 and in vivo = 40.9) present. The results suggest that both in vitro and in vivo digestibility of maize starch is affected by the amylose content and surface area of the granules. The current evaluation suggests that the physiological occurrence of RS from maize starch might be predictable by reference to the in vitro RS value.


1986 ◽  
Vol 38 (4) ◽  
pp. 118-119 ◽  
Author(s):  
C. P. Villareal ◽  
B. O. Juliano

1995 ◽  
Vol 73 (7) ◽  
pp. 982-990 ◽  
Author(s):  
R. D. Hill ◽  
S. M. Gubbels ◽  
L. Boros ◽  
M. J. Sumner ◽  
A. W. MacGregor

The location of an endogenous α-amylase/subtilisin inhibitor in developing and germinating barley (Hordeum vulgare, cv. Bonanza) was determined using immunohistochemical techniques. The inhibitor was found within protein bodies of cells containing starch granules in the starchy endosperm and embryo of developing caryopses. It could be detected as early as 2 weeks postanthesis in both organs. Upon germination, inhibitor was released from protein bodies, resulting in increased detection of the protein in regions of the starchy endosperm in which storage mobilization was occurring. Antibodies to α-amylase revealed large quantities of this protein in the same regions. Key words: α-amylase, α-amylase/subtilisin inhibitor, barley, germination, kernel development, starch.


2016 ◽  
Vol 96 (3) ◽  
pp. 404-412 ◽  
Author(s):  
Shian Shen ◽  
Hongwei Hou ◽  
Chunbang Ding ◽  
Deng-Jin Bing ◽  
Zhen-Xiang Lu

Protein and starch are two major components in field peas. In this study, we investigated the starch morphologies, compositions, and thermal properties between high protein peas (approximately 30%) and other market types of field peas (yellow, green, maple, and marrowfat peas, with approximately 23% protein contents). For the shape and size, high protein peas had the compound starch granules that could be easily fragmented into small irregular and polygonal granules, whereas other pea types had oval or kidney-like starch granules with high percentage of large granule sizes. High protein peas had significantly lower starch contents (27.2%–34.2%) than other pea types (45.5%–47.4%). However, the amylose content (74.6%–89.2%) in high protein peas were significantly higher that of other pea types (50.1%–54.1%). Our differential scanning calorimeter (DSC) data showed that the onset temperature (To), peak temperature (Tp), and conclusion temperature (Tc) of starch gelatinization in high protein peas were significantly higher than those of other pea types, whereas the enthalpy change (ΔH) of high protein peas was significantly lower than those of other pea types. The unique properties of high protein peas characterized in this study provided useful information to further improve pea quality.


1995 ◽  
Vol 7 (4) ◽  
pp. 613-622 ◽  
Author(s):  
Zong-Yang Wang ◽  
Fei-Qin Zheng ◽  
Ge-Zhi Shen ◽  
Ji-Ping Gao ◽  
D. Peter Snustad ◽  
...  

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