Production of amylopectin and high-amylose starch in separate potato genotypes

Starch is one of the most important processed products from agriculture. Two main outlets can be identified; starch is either enzymatically processed for the production of sweeteners and as raw material for fermentation or channelled to various applications as dry starch. Native or chemically modified starches are utilized in food as well as non-food applications, where the specific physicochemical properties are main determinants for their respective use. Starch consists of two different molecules, amylose and amylopectin. To be able to take the full benefit of the unique properties of either component it is of interest to divide the production of amylose and amylopectin into separate plant genotypes. In the presented work, potatoes producing either amylopectin or high-amylose starch were achieved using genetic modification. For potato transformation a highly efficient protocol was developed for a herbicide selection gene instead of the commonly used nptII antibiotic selection gene. In order to achieve respective starch qualities, the expression of genes important for amylopectin or amylose synthesis was silenced. Antisense technology as well as the expression of dsRNA was investigated where the expression of dsRNA was determined to be at least ten-fold more efficient for gene silencing. An added benefit of dsRNA expression was that a higher fraction of silenced transgenic lines compared to the use antisense were associated with single copy T-DNA integrations. One amylopectin potato line was furthermore characterized regarding genetic and chemical composition. The T-DNA was found integrated as an inverted repeat with the inverted repeat region extending into potato chromosomal DNA. This transgenic locus was found to be more consistent with integration into a double-stranded chromosomal break than insertion by a mechanism nicking one strand of the locus. The high-amylose trait generally resulted in a higher tuber fresh weight yield, much elevated sugar levels and a decreased starch content. Amylose levels were obtained where very limited amounts of material recognizable as amylopectin could be found. The production of amylopectin and amylose was divided into separate genotypes but additional factors are needed to be able to produce amylose at levels comparable to starch contents of cultivated potatoes

Integrated functions among multiple starch synthases determine both amylopectin chain length and branch linkage location in Arabidopsis leaf starch

This study assessed the impact on starch metabolism in Arabidopsis leaves of simultaneously eliminating multiple soluble starch synthases (SS) from among SS1, SS2, and SS3. Double mutant ss1- ss2- or ss1- ss3- lines were generated using confirmed null mutations. These were compared to the wild type, each single mutant, and ss1- ss2- ss3- triple mutant lines grown in standardized environments. Double mutant plants developed similarly to the wild type, although they accumulated less leaf starch in both short-day and long-day diurnal cycles. Despite the reduced levels in the double mutants, lines containing only SS2 and SS4, or SS3 and SS4, are able to produce substantial amounts of starch granules. In both double mutants the residual starch was structurally modified including higher ratios of amylose:amylopectin, altered glucan chain length distribution within amylopectin, abnormal granule morphology, and altered placement of α(1→6) branch linkages relative to the reducing end of each linear chain. The data demonstrate that SS activity affects not only chain elongation but also the net result of branch placement accomplished by the balanced activities of starch branching enzymes and starch debranching enzymes. SS3 was shown partially to overlap in function with SS1 for the generation of short glucan chains within amylopectin. Compensatory functions that, in some instances, allow continued residual starch production in the absence of specific SS classes were identified, probaby accomplished by the granule bound starch synthase GBSS1.ANR Génoplante GPLA0611GEuropean Union-FEDER, Région Nord Pas de Calais ARCir PlantTEQ5National Science Foundation DBI-0209789Comisión Interministerial de Ciencia y Tecnología BIO2009-07040Junta de Andalucía P09-CVI-470

Liver transplantation for type I and type IV glycogen storage disease

Progressive liver failure or hepatic complications of the primary disease led to orthotopic liver transplantation in eight children with glycogen storage disease over a 9-year period. One patient had glycogen storage disease (GSD) type I (von Gierke disease) and seven patients had type IV GSD (Andersen disease). As previously reported [19], a 16.5-year-old-girl with GSD type I was successfully treated in 1982 by orthotopic liver transplantation under cyclosporine and steroid immunosuppression. The metabolic consequences of the disease have been eliminated, the renal function and size have remained normal, and the patient has lived a normal young adult life. A late portal venous thrombosis was treated successfully with a distal splenorenal shunt. Orthotopic liver transplantation was performed in seven children with type N GSD who had progressive hepatic failure. Two patients died early from technical complications. The other five have no evidence of recurrent hepatic amylopectinosis after 1.1–5.8 postoperative years. They have had good physical and intellectual maturation. Amylopectin was found in many extrahepatic tissues prior to surgery, but cardiopathy and skeletal myopathy have not developed after transplantation. Postoperative heart biopsies from patients showed either minimal amylopectin deposits as long as 4.5 years following transplantation or a dramatic reduction in sequential biopsies from one patient who initially had dense myocardial deposits. Serious hepatic derangement is seen most commonly in types T and IV GSD. Liver transplantation cures the hepatic manifestations of both types. The extrahepatic deposition of abnormal glycogen appears not to be problematic in type I disease, and while potentially more threatening in type IV disease, may actually exhibit signs of regression after hepatic allografting

Liver transplantation for type IV glycogen storage disease

TYPE IV glycogen storage disease is a rare autosomal recessive disorder (also called Andersen's disease1 or amylopectinosis) in which the activity of branching enzyme alpha-1, 4-glucan: alpha-1, 4-glucan 6-glucosyltransferase is deficient in the liver as well as in cultured skin fibroblasts and other tissues.2,3 This branching enzyme is responsible for creating branch points in the normal glycogen molecule. In the relative or absolute absence of this enzyme, an insoluble and irritating form of glycogen, an amylopectin-like polysaccharide that resembles plant starch, accumulates in the cells. The amylopectin-like form is less soluble than normal glycogen, with longer outer and inner chains. © 1991, Massachusetts Medical Society. All rights reserved

Comparison of Short-grain Rice Cultivars Grown in Japan and the United States

Although short-grain rice accounts for less than 2% of U.S. rice production, the demand for short-grain rice is expected to increase because of the increasing popularity of sushi and sake. The objective of this study was to compare the physical, chemical and textural properties of short-grain rice cultivars grown in Japan and in the U.S. Seven short-grain rice cultivars from the 2016 crop year were collected, including five cultivars (Hatsushimo, Kinuhikari, Koshihikari, Nanatsuboshi, and Yumepirika) grown and purchased in grocery stores in Japan, one (RU9601099) grown in Arkansas, and one (CH-202) grown in California. The rice cultivars were characterized for kernel dimensions, color, chemical composition, amylopectin fine structure, and gelatinization, pasting and textural properties. RU9601099 had a smaller kernel width and a greater whiteness (L*) value than the other cultivars. Japanese cultivars were comparable in protein content, while RU9601099 had the greatest and CH-202 had the lowest protein content. RU9601099, CH-202 and Kinuhikari shared a similar value of average amylopectin chain length and gelatinization temperatures and enthalpy, which were significantly greater than the other cultivars. Kinuhikari and RU9601099 displayed greater peak and trough viscosities, whereas Hatsushimo and Nanatsuboshi had lower peak and breakdown viscosities. When cooked, the Japanese cultivars exhibited significantly greater hardness than the U.S. cultivars. Based on Ward’s cluster analysis considering all data, CH-202 shared similar properties with Kinuhikari, and RU9601099 was distinctively different from the other cultivars in most properties. The information obtained from this study will help future cultivar development and marketing of existing short-grain rice cultivars in the U.S

Allelic effects on starch structure and properties of six starch biosynthetic genes in a rice recombinant inbred line population

BACKGROUND: The genetic diversity of six starch biosynthetic genes (Wx, SSI, SSIIa, SBEI, SBEIIa and SBEIIb) in indica and japonica rices opens an opportunity to produce a new variety with more favourable grain starch quality. However, there is limited information about the effects of these six gene allele combinations on starch structure and properties. A recombinant inbred line population from a cross between indica and japonica varieties offers opportunities to combine specific alleles of the six genes. RESULTS: The allelic (indica vs japonica) effects of six starch biosynthetic genes on starch structure, functional properties, and abundance of granule bound proteins in rice grains were investigated in a common genetic background using a recombinant inbred line population. The indica Wx (Wxi) allele played a major role while indica SSI (SSIi), japonica SSIIa (SSIIaj) and indica SBEI (SBEIi) alleles had minor roles on the increase of amylose content. SSIIaj and japonica SBEIIb (SBEIIbj) alleles had a major and a minor role on high ratio of ∑DP ≤ 10 to ∑DP ≤ 24 fractions (RCL10/24), respectively. Both major alleles (Wxi and SSIIaj) reduced peak viscosity (PV), onset, peak and end gelatinization temperatures (GTs) of amylopectin, and increased amylose-lipid complex dissociation enthalpy compared with their counterpart-alleles, respectively. SBEIIai and SBEIIbj decreased PV, whereas SSIi and SBEIIbj decreased FV. SBEIi reduced setback viscosity and gelatinization enthalpy. RCL10/24 of chain length distribution in amylopectin is negatively correlated with PV and BD of paste property and GTs of thermal properties. We also report RILs with superior starch properties combining Wxi, SSIj, SSIIaj, SBEIi and SBEIIbj alleles. Additionally, a clear relation is drawn to starch biosynthetic gene alleles, starch structure, properties, and abundance of granule bound starch biosynthetic enzymes inside starch granules. CONCLUSIONS: Rice Wxi and SSIIaj alleles play major roles, while SSIi, SBEIi, SBEIIai and SBEIIbj alleles have minor roles in the determination of starch properties between indica and japonica rice through starch structural modification. The combination of these alleles is a key factor for starch quality improvement in rice breeding programs. RCL10/24 value is critical for starch structure and property determination.Jixun Luo was supported by CSC (Chinese Scholarship Council) and Australian National University scholarships. This work was funded by CSIRO Food Future National Research Flagship

Characterization of Jasmine Rice Cultivars Grown in the United States

Jasmine rice from Thailand accounts for about 60-70% of U.S. imported rice, primarily due to its preference by ethnic Asians as well as general American population. Recently new U.S. jasmine rice cultivars have been developed independently at three rice research stations in Arkansas, California, and Louisiana, but their properties have not been characterized. The objective of this research was to characterize and compare the physical appearance, chemical composition, thermal and pasting properties, cooked rice texture and starch structures of the newly-developed U.S. jasmine rice from Arkansas, California and Louisiana, to be compared with jasmine rice samples from Thailand. In general, the U.S. varieties had smaller length/width ratios, darker color, and greater ash and lipid contents than the Thai controls. The Arkansas samples were similar to each other as well as one Louisiana sample, CLJ01 2017, and the other Louisiana samples were similar to each other, but rice of both origins were different from Thai jasmine. Calaroma-201 was found to be the most similar to the Thai jasmine rice out of the U.S. varieties from Ward’s hierarchical cluster analysis of all attributes. These findings can help the U.S. rice industry to develop U.S. jasmine rice cultivars closer to Thai jasmine rice

Prediction of rice texture from starch profiles measured using high-performance liquid chromatography

Starch determines a large proportion of the textural properties of cooked rice. The amylose: amylopectin ratio plays a significant role in the functionality of native starch. In this study a medium-grain rice cultivar, ‘Bengal’, was used for starch structure characterization using high performance size-exclusion chromatography (HPSEC). This cultivar is characterized by having lower amylose content (15% to 20%) than long grain cultivars and being sticky when cooked, similar to short-grain cultivars. Rice samples were harvested in 1999 from five locations around Arkansas at state verification trials where cultural practices are closely monitored. Samples of this cultivar stored at a specified moisture level for a pre-determined period of time were also subjected to texture analysis by means of a Texture Analyzer. The data measured with the HPSEC was related to instrumental texture attributes. Chemical characterization data (carbohydrate profiles) of rice samples were used to predict texture attributes of cooked rice such as hardness and stickiness. Instrumental texture attributes of hardness and stickiness were successfully predicted for Bengal rice from starch-profile data obtained though HPSEC analyses. Both attributes proved to be well predicted, based on their high coefficients of determination of 0.97 and 0.85, respectively. The statistical analysis indicates that starch structure characterization using HPSEC may be related to instrumental measurements of texture attributes