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Luo X, Huang Q, Fu X, Kraithong S, Hu Y, Yuan Y, Bao J, Zhang B. In vitro fecal fermentation characteristics of mutant rice starch depend more on amylose content than crystalline structure. Carbohydr Polym 2023; 307:120606. [PMID: 36781271 DOI: 10.1016/j.carbpol.2023.120606] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2022] [Revised: 01/07/2023] [Accepted: 01/17/2023] [Indexed: 01/26/2023]
Abstract
To obtain the relation between rice starch features and fermentation characteristics, rice starches with various polymorphic types and apparent amylose contents were subjected to in vitro fecal fermentation. Gas and short-chain fatty acid production was evaluated as a function of fermentation time, and the microbial responses were monitored by 16S rRNA sequencing technique at the end of fermentation. Regardless of polymorphic type, three high-amylose mutant rice starches (i.e., GM03, A-type; BP577, B-type; Wx21TT, C-type) displayed significantly slower fermentation rate during the first 12 h and higher final butyrate yield (17.6-17.9 mM) compared to the A-type normal starches (9311 and Wx22TT), and promoted the proliferation of Roseburia. However, A-type normal rice starches presented higher propionate production, and increased the growth of Bacteroides and Megamonas. The principal component and redundancy analyses indicated that three high-amylose mutant rice starches showed similar abundance and migration of microbial communities, and the apparent amylose content was closely correlated with the abundance of their five key amplicon sequence variants. Our results demonstrated that amylose content might be a controlling factor in determining the fermentation properties of rice starches than crystalline structure.
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Affiliation(s)
- Xiaoyi Luo
- School of Food Science and Engineering, Guangdong Province Key Laboratory for Green Processing of Natural Products and Product Safety, South China University of Technology, Guangzhou 510640, China
| | - Qiang Huang
- School of Food Science and Engineering, Guangdong Province Key Laboratory for Green Processing of Natural Products and Product Safety, South China University of Technology, Guangzhou 510640, China
| | - Xiong Fu
- School of Food Science and Engineering, Guangdong Province Key Laboratory for Green Processing of Natural Products and Product Safety, South China University of Technology, Guangzhou 510640, China
| | - Supaluck Kraithong
- School of Food Science and Engineering, Guangdong Province Key Laboratory for Green Processing of Natural Products and Product Safety, South China University of Technology, Guangzhou 510640, China
| | - Yaqi Hu
- Institute of Nuclear Agricultural Sciences, Key Laboratory of Nuclear Agricultural Sciences of Ministry of Agriculture and Zhejiang Province, College of Agriculture and Biotechnology, Zhejiang University, Zijingang Campus, Hangzhou 310058, China
| | - Yang Yuan
- School of Chemistry and Chemical Engineering, Guangzhou University, Guangzhou 510006, China
| | - Jinsong Bao
- Institute of Nuclear Agricultural Sciences, Key Laboratory of Nuclear Agricultural Sciences of Ministry of Agriculture and Zhejiang Province, College of Agriculture and Biotechnology, Zhejiang University, Zijingang Campus, Hangzhou 310058, China.
| | - Bin Zhang
- School of Food Science and Engineering, Guangdong Province Key Laboratory for Green Processing of Natural Products and Product Safety, South China University of Technology, Guangzhou 510640, China; Overseas Expertise Introduction Center for Discipline Innovation of Food Nutrition and Human Health (111 Center), Guangzhou 510640, China.
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Screening methods for cereal grains with different starch components: A mini review. J Cereal Sci 2022. [DOI: 10.1016/j.jcs.2022.103557] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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3
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Nakamura Y, Kubo A, Ono M, Yashiro K, Matsuba G, Wang Y, Matsubara A, Mizutani G, Matsuki J, Kainuma K. Changes in fine structure of amylopectin and internal structures of starch granules in developing endosperms and culms caused by starch branching enzyme mutations of japonica rice. PLANT MOLECULAR BIOLOGY 2022; 108:481-496. [PMID: 35099666 DOI: 10.1007/s11103-021-01237-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Accepted: 12/21/2021] [Indexed: 06/14/2023]
Abstract
BEIIb plays a specific role in determining the structure of amylopectin in rice endosperm, whereas BEIIa plays the similar role in the culm where BEIIb is absent. Cereals have three types of starch branching enzymes (BEs), BEI, BEIIa, and BEIIb. It is widely known that BEIIb is specifically expressed in the endosperm and plays a distinct role in the structure of amylopectin because in its absence the amylopectin type changes to the amylose-extender-type (ae-type) or B-type from the wild-type or A-type and this causes the starch crystalline allomorph to the B-type from the wild-type A-type. This study aimed to clarify the role of BEIIa in the culm where BEIIb is not expressed, by using a be2a mutant in comparison with results with be2b and be1 mutants. The results showed that the amylopectin structure exhibited the B-type in the be2a culm compared with the A-type in the wild-type culm. The starch granules from the be2a culm also showed the B-type like allomorph when examined by X-ray diffraction analysis and optical sum frequency generation spectroscopy. Both amylopectin chain-length profile and starch crystalline properties were found to be the A-type at the very early stage of endosperm development at 4-6 days after pollination (DAP) even in the be2b mutant. All these results support a view that in the culm as well as in the endosperm at 4-6 DAP, BEIIa can play the role of BEIIb which has been well documented in maturing endosperm. The possible mechanism as to how BEIIa can play its role is discussed.
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Affiliation(s)
- Yasunori Nakamura
- Starch Technologies, Co., Ltd., Akita Prefectural University, Shimoshinjo-Nakano, Akita-City, Akita, 010-0195, Japan.
- Akita Natural Science Laboratory, 25-44 Oiwake-Nishi, Tennoh, Katagami, Akita, 010-0101, Japan.
- Faculty of Bioresource Sciences, Akita Prefectural University, Shimoshinjo-Nakano, Akita-City, Akita, 010-0195, Japan.
| | - Akiko Kubo
- Faculty of Bioresource Sciences, Akita Prefectural University, Shimoshinjo-Nakano, Akita-City, Akita, 010-0195, Japan
| | - Masami Ono
- Starch Technologies, Co., Ltd., Akita Prefectural University, Shimoshinjo-Nakano, Akita-City, Akita, 010-0195, Japan
- Faculty of Bioresource Sciences, Akita Prefectural University, Shimoshinjo-Nakano, Akita-City, Akita, 010-0195, Japan
| | - Kazuki Yashiro
- Graduate School of Organic Materials Engineering, Yamagata University, 4-3-16 Jonan, Yonezawa, Yamagata, 992-8510, Japan
| | - Go Matsuba
- Graduate School of Organic Materials Engineering, Yamagata University, 4-3-16 Jonan, Yonezawa, Yamagata, 992-8510, Japan
| | - Yifei Wang
- School of Materials Science, Japan Advanced Institute of Science and Technology, 1-1 Asahidai, Nomi, Ishikawa, 923-1292, Japan
| | - Akira Matsubara
- School of Materials Science, Japan Advanced Institute of Science and Technology, 1-1 Asahidai, Nomi, Ishikawa, 923-1292, Japan
| | - Goro Mizutani
- School of Materials Science, Japan Advanced Institute of Science and Technology, 1-1 Asahidai, Nomi, Ishikawa, 923-1292, Japan
| | - Junko Matsuki
- Food Research Institute, National Agriculture and Food Research Organization, 2-1-12 Kannondai, Tsukuba, Ibaraki, 305-8642, Japan
| | - Keiji Kainuma
- Science Academy of Tsukuba, 2-20-3 Takezono, Tsukuba, Ibaraki, 305-0032, Japan
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Tappiban P, Hu Y, Deng J, Zhao J, Ying Y, Zhang Z, Xu F, Bao J. Relative importance of branching enzyme isoforms in determining starch fine structure and physicochemical properties of indica rice. PLANT MOLECULAR BIOLOGY 2022; 108:399-412. [PMID: 34750721 DOI: 10.1007/s11103-021-01207-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Accepted: 10/05/2021] [Indexed: 05/24/2023]
Abstract
Down-regulation of starch branching enzymes alters fine structure and starch properties, especially the B-type crystalline pattern and extremely high amylose content identified in the BEIIb-deficiency mutant in the indica rice. The relative importance of the starch branching enzymes in determining the molecular fine structure and starch functional properties were uncovered in this study. An indica rice, Guangluai 4 with high amylose content (AC) and high gelatinization temperature (GT) was used to generate the clustered regularly interspaced short palindromic repeats (CRISPR)/associated protein-9 (Cas9) knockout lines. Five mutant lines were identified including be1-1, be1-2, be2a-1, be2a-2 and be2b-1, and analysis of western blot showed the CRISPR/Cas9 system was successful in inducing mutations in the targeted genes. AC of be2b-1 (34.1%) was greater than that of wild type (WT) (27.4%) and other mutants. Mutations of either BEI or BEIIa did not alter the starch crystallite pattern (A-type). The BEIIb deficiency caused an opaque endosperm phenotype, changed the crystallite pattern from A- to B-type, and dramatically increased the degree of ordered structure, the relative proportion of amylose chains and intermediate to long amylopectin chains, average chain length of amylopectin molecules as well as GT. The BEIIa deficiency had no effect on the proportion of amylose chains, the length of amylopectin intermediate-long chains, conclusion temperature and enthalpy of gelatinization. Down-regulation of BEI increased the proportion of shortest amylopectin chains (fa) but decreased the proportion of long amylopectin chains (fb2 and fb3), leading to a lower GT. It is concluded that the relative importance in determining starch fine structures and functionality was in the order of BEIIb > BEI > BEIIa. Our results provide new information for utilizations of BE-deficient mutants in rice quality breeding.
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Affiliation(s)
- Piengtawan Tappiban
- Key Laboratory of Nuclear Agricultural Sciences of Ministry of Agriculture and Zhejiang Province, Institute of Nuclear Agricultural Sciences, College of Agriculture and Biotechnology, Zhejiang University, Zijingang Campus, Hangzhou, 310058, China
| | - Yaqi Hu
- Key Laboratory of Nuclear Agricultural Sciences of Ministry of Agriculture and Zhejiang Province, Institute of Nuclear Agricultural Sciences, College of Agriculture and Biotechnology, Zhejiang University, Zijingang Campus, Hangzhou, 310058, China
| | - Jiaming Deng
- Department of Applied Bioscience, College of Agriculture and Biotechnology, Zhejiang University, Zijingang Campus, Hangzhou, 310058, China
| | - Jiajia Zhao
- Key Laboratory of Nuclear Agricultural Sciences of Ministry of Agriculture and Zhejiang Province, Institute of Nuclear Agricultural Sciences, College of Agriculture and Biotechnology, Zhejiang University, Zijingang Campus, Hangzhou, 310058, China
| | - Yining Ying
- Key Laboratory of Nuclear Agricultural Sciences of Ministry of Agriculture and Zhejiang Province, Institute of Nuclear Agricultural Sciences, College of Agriculture and Biotechnology, Zhejiang University, Zijingang Campus, Hangzhou, 310058, China
| | - Zhongwei Zhang
- Key Laboratory of Nuclear Agricultural Sciences of Ministry of Agriculture and Zhejiang Province, Institute of Nuclear Agricultural Sciences, College of Agriculture and Biotechnology, Zhejiang University, Zijingang Campus, Hangzhou, 310058, China
| | - Feifei Xu
- Key Laboratory of Nuclear Agricultural Sciences of Ministry of Agriculture and Zhejiang Province, Institute of Nuclear Agricultural Sciences, College of Agriculture and Biotechnology, Zhejiang University, Zijingang Campus, Hangzhou, 310058, China.
| | - Jinsong Bao
- Key Laboratory of Nuclear Agricultural Sciences of Ministry of Agriculture and Zhejiang Province, Institute of Nuclear Agricultural Sciences, College of Agriculture and Biotechnology, Zhejiang University, Zijingang Campus, Hangzhou, 310058, China.
- Hainan Institute of Zhejiang University, Yazhou District, Sanya, 572025, China.
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Zhao S, Wang H, Chen H, Lin L, Liu Q, Wei C. Screening and identification of rice non-floury endosperm mutants with different starch components. J Cereal Sci 2022. [DOI: 10.1016/j.jcs.2021.103397] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Sato Y, Tsuda K, Yamagata Y, Matsusaka H, Kajiya-Kanegae H, Yoshida Y, Agata A, Ta KN, Shimizu-Sato S, Suzuki T, Nosaka-Takahashi M, Kubo T, Kawamoto S, Nonomura KI, Yasui H, Kumamaru T. Collection, preservation and distribution of Oryza genetic resources by the National Bioresource Project RICE (NBRP-RICE). BREEDING SCIENCE 2021; 71:291-298. [PMID: 34776736 PMCID: PMC8573556 DOI: 10.1270/jsbbs.21005] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Accepted: 03/15/2021] [Indexed: 05/26/2023]
Abstract
Biological resources are the basic infrastructure of bioscience research. Rice (Oryza sativa L.) is a good experimental model for research in cereal crops and monocots and includes important genetic materials used in breeding. The availability of genetic materials, including mutants, is important for rice research. In addition, Oryza species are attractive to researchers for both finding useful genes for breeding and for understanding the mechanism of genome evolution that enables wild plants to adapt to their own habitats. NBRP-RICE contributes to rice research by promoting the usage of genetic materials, especially wild Oryza accessions and mutant lines. Our activity includes collection, preservation and distribution of those materials and the provision of basic information on them, such as morphological and physiological traits and genomic information. In this review paper, we introduce the activities of NBRP-RICE and our database, Oryzabase, which facilitates the access to NBRP-RICE resources and their genomic sequences as well as the current situation of wild Oryza genome sequencing efforts by NBRP-RICE and other institutes.
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Affiliation(s)
- Yutaka Sato
- National Institute of Genetics, 1111 Yata, Mishima, Shizuoka 411-8540, Japan
- Department of Genetics, School of Life Science, SOKENDAI (The Graduate University for Advanced Studies), 1111 Yata, Mishima, Shizuoka 411-8540, Japan
| | - Katsutoshi Tsuda
- National Institute of Genetics, 1111 Yata, Mishima, Shizuoka 411-8540, Japan
- Department of Genetics, School of Life Science, SOKENDAI (The Graduate University for Advanced Studies), 1111 Yata, Mishima, Shizuoka 411-8540, Japan
| | - Yoshiyuki Yamagata
- Faculty of Agriculture, Kyushu University, 744 Motooka, Nishi-ku Fukuoka 819-0395, Japan
| | - Hiroaki Matsusaka
- Faculty of Agriculture, Kyushu University, 744 Motooka, Nishi-ku Fukuoka 819-0395, Japan
| | - Hiromi Kajiya-Kanegae
- Research Center for Agricultural Information Technology, National Agriculture and Food Research Organization, Chiyoda-ku, Tokyo 100-0013, Japan
| | - Yuri Yoshida
- National Institute of Genetics, 1111 Yata, Mishima, Shizuoka 411-8540, Japan
| | - Ayumi Agata
- National Institute of Genetics, 1111 Yata, Mishima, Shizuoka 411-8540, Japan
| | - Kim Nhung Ta
- National Institute of Genetics, 1111 Yata, Mishima, Shizuoka 411-8540, Japan
| | - Sae Shimizu-Sato
- National Institute of Genetics, 1111 Yata, Mishima, Shizuoka 411-8540, Japan
| | - Toshiya Suzuki
- National Institute of Genetics, 1111 Yata, Mishima, Shizuoka 411-8540, Japan
- Department of Genetics, School of Life Science, SOKENDAI (The Graduate University for Advanced Studies), 1111 Yata, Mishima, Shizuoka 411-8540, Japan
| | - Misuzu Nosaka-Takahashi
- National Institute of Genetics, 1111 Yata, Mishima, Shizuoka 411-8540, Japan
- Department of Genetics, School of Life Science, SOKENDAI (The Graduate University for Advanced Studies), 1111 Yata, Mishima, Shizuoka 411-8540, Japan
| | - Takahiko Kubo
- Faculty of Agriculture, Kyushu University, 744 Motooka, Nishi-ku Fukuoka 819-0395, Japan
| | - Shoko Kawamoto
- National Institute of Genetics, 1111 Yata, Mishima, Shizuoka 411-8540, Japan
- Department of Genetics, School of Life Science, SOKENDAI (The Graduate University for Advanced Studies), 1111 Yata, Mishima, Shizuoka 411-8540, Japan
| | - Ken-Ichi Nonomura
- National Institute of Genetics, 1111 Yata, Mishima, Shizuoka 411-8540, Japan
- Department of Genetics, School of Life Science, SOKENDAI (The Graduate University for Advanced Studies), 1111 Yata, Mishima, Shizuoka 411-8540, Japan
| | - Hideshi Yasui
- Faculty of Agriculture, Kyushu University, 744 Motooka, Nishi-ku Fukuoka 819-0395, Japan
| | - Toshihiro Kumamaru
- Faculty of Agriculture, Kyushu University, 744 Motooka, Nishi-ku Fukuoka 819-0395, Japan
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Ikegaya T, Ashida K. Genetic region responsible for the differences of starch properties in two glutinous rice cultivars in Hokkaido, Japan. BREEDING SCIENCE 2021; 71:375-383. [PMID: 34776744 PMCID: PMC8573546 DOI: 10.1270/jsbbs.20163] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/25/2020] [Accepted: 03/09/2021] [Indexed: 06/13/2023]
Abstract
Starch properties are major determinants of grain quality and food characteristics in rice (Oryza sativa L.). Control of starch properties will lead to the development of rice cultivars with desirable characteristics. We performed quantitative trait locus analysis and detected a putative region on chromosome 2 associated with phenotypic variation of starch properties in two glutinous rice varieties developed in the Hokkaido region of Japan: 'Kitayukimochi', which has a low pasting temperature and creates soft rice cakes, and 'Shirokumamochi', which has a high pasting temperature and creates hard rice cakes. Starch branching enzyme IIb (SbeIIb) was identified as a candidate gene within the region. Sequence analysis of SbeIIb in parental lines identified two single-nucleotide polymorphisms (SNPs) with non-synonymous mutations in the coding region of the 'Shirokumamochi' genotype (SbeIIbsr ). We genotyped over 100 rice cultivars, including 28 rice varieties in the Honshu region of Japan, using the CAPS marker, which was designed using one of the SNPs. However, SbeIIbsr was not found in rice cultivars in Honshu. Distribution analysis indicated that SbeIIbsr was introduced to the rice breeding population in Hokkaido from the American variety 'Cody' via the Hokkaido cultivar 'Kitaake'. As a result, SbeIIbsr was distributed only in progenies of 'Kitaake'.
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Affiliation(s)
- Tomohito Ikegaya
- National Agriculture and Food Research Organization (NARO), Hokkaido Agricultural Research Center, Sapporo, Hokkaido 062-8555, Japan
| | - Kanae Ashida
- National Agriculture and Food Research Organization (NARO), Hokkaido Agricultural Research Center, Sapporo, Hokkaido 062-8555, Japan
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de Freitas KEJ, dos Santos RS, Busanello C, de Carvalho Victoria F, Lopes JL, Wing RA, de Oliveira AC. Starch Synthesis-Related Genes (SSRG) Evolution in the Genus Oryza. PLANTS 2021; 10:plants10061057. [PMID: 34070565 PMCID: PMC8229393 DOI: 10.3390/plants10061057] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/27/2021] [Revised: 04/14/2021] [Accepted: 04/14/2021] [Indexed: 11/18/2022]
Abstract
Cooking quality is an important attribute in Common/Asian rice (Oryzasativa L.) varieties, being highly dependent on grain starch composition. This composition is known to be highly dependent on a cultivar’s genetics, but the way in which their genes express different phenotypes is not well understood. Further analysis of variation of grain quality genes using new information obtained from the wild relatives of rice should provide important insights into the evolution and potential use of these genetic resources. All analyses were conducted using bioinformatics approaches. The analysis of the protein sequences of grain quality genes across the Oryza suggest that the deletion/mutation of amino acids in active sites result in variations that can negatively affect specific steps of starch biosynthesis in the endosperm. On the other hand, the complete deletion of some genes in the wild species may not affect the amylose content. Here we present new insights for Starch Synthesis-Related Genes (SSRGs) evolution from starch-specific rice phenotypes.
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Affiliation(s)
- Karine E. Janner de Freitas
- Centro de desenvolvimento Tecnológico—CDTec, Graduate Program in biotechnology, Capão do Leão Campus, Federal de Pelotas, Pelotas 96160, Brazil; (K.E.J.d.F.); (C.B.); (J.L.L.)
| | | | - Carlos Busanello
- Centro de desenvolvimento Tecnológico—CDTec, Graduate Program in biotechnology, Capão do Leão Campus, Federal de Pelotas, Pelotas 96160, Brazil; (K.E.J.d.F.); (C.B.); (J.L.L.)
| | - Filipe de Carvalho Victoria
- Núcleo de Estudos da Vegetação Antártica—NEVA, Campus São Gabriel Federal do Pampa (UNIPAMPA), São Gabriel 97030, Brazil;
| | - Jennifer Luz Lopes
- Centro de desenvolvimento Tecnológico—CDTec, Graduate Program in biotechnology, Capão do Leão Campus, Federal de Pelotas, Pelotas 96160, Brazil; (K.E.J.d.F.); (C.B.); (J.L.L.)
| | - Rod A. Wing
- The School of Plant Sciences, Ecology & Evolutionary Biology, Arizona Genomics Institute, Tucson, AZ 97030, USA;
- Center for Desert Agriculture, King Abdullah University of Science & Technology, Thuwal 23955, Saudi Arabia
| | - Antonio Costa de Oliveira
- Centro de desenvolvimento Tecnológico—CDTec, Graduate Program in biotechnology, Capão do Leão Campus, Federal de Pelotas, Pelotas 96160, Brazil; (K.E.J.d.F.); (C.B.); (J.L.L.)
- Correspondence:
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9
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Miura S, Koyama N, Crofts N, Hosaka Y, Abe M, Fujita N. Generation and Starch Characterization of Non-Transgenic BEI and BEIIb Double Mutant Rice (Oryza sativa) with Ultra-High Level of Resistant Starch. RICE (NEW YORK, N.Y.) 2021; 14:3. [PMID: 33409744 PMCID: PMC7788159 DOI: 10.1186/s12284-020-00441-0] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2020] [Accepted: 11/23/2020] [Indexed: 05/21/2023]
Abstract
BACKGROUND Cereals high in resistant starch (RS) are gaining popularity, as their intake is thought to help manage diabetes and prediabetes. Number of patients suffering from diabetes is also increasing in Asian countries where people consume rice as a staple food, hence generation of practically growable high RS rice line has been anticipated. It is known that suppression of starch branching enzyme (BE) IIb increases RS content in cereals. To further increase RS content and for more practical use, we generated a non-transgenic be1 be2b double mutant rice (Oryza sativa) line, which completely lacked both proteins, by crossing a be1 mutant with a be2b mutant. RESULTS The be1 be2b mutant showed a decrease in intermediate amylopectin chains and an increase in long amylopectin chains compared with be2b. The amylose content of be1 be2b mutant (51.7%) was the highest among all pre-existing non-transgenic rice lines. To understand the effects of chewing cooked rice and cooking rice flour on RS content, RS content of mashed and un-mashed cooked rice as well as raw and gelatinized rice flour were measured using be1 be2b and its parent mutant lines. The RS contents of mashed cooked rice and raw rice flour of be1 be2b mutant (28.4% and 35.1%, respectively) were 3-fold higher than those of be2b mutant. Gel-filtration analyses of starch treated with digestive enzymes showed that the RS in be1 be2b mutant was composed of the degradation products of amylose and long amylopectin chains. Seed weight of be1 be2b mutant was approximately 60% of the wild type and rather heavier than that of be2b mutant. CONCLUSIONS The endosperm starch in be1 be2b double mutant rice were enriched with long amylopectin chains. This led to a great increase in RS content in cooked rice grains and rice flour in be1 be2b compared with be2b single mutant. be1 be2b generated in this study must serve as a good material for an ultra-high RS rice cultivar.
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Affiliation(s)
- Satoko Miura
- Department of Biological Production, Akita Prefectural University, Akita, 010-0195 Japan
| | - Nana Koyama
- Department of Biological Production, Akita Prefectural University, Akita, 010-0195 Japan
| | - Naoko Crofts
- Department of Biological Production, Akita Prefectural University, Akita, 010-0195 Japan
| | - Yuko Hosaka
- Department of Biological Production, Akita Prefectural University, Akita, 010-0195 Japan
| | - Misato Abe
- Department of Biological Production, Akita Prefectural University, Akita, 010-0195 Japan
| | - Naoko Fujita
- Department of Biological Production, Akita Prefectural University, Akita, 010-0195 Japan
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Baysal C, He W, Drapal M, Villorbina G, Medina V, Capell T, Khush GS, Zhu C, Fraser PD, Christou P. Inactivation of rice starch branching enzyme IIb triggers broad and unexpected changes in metabolism by transcriptional reprogramming. Proc Natl Acad Sci U S A 2020; 117:26503-26512. [PMID: 33020297 PMCID: PMC7584904 DOI: 10.1073/pnas.2014860117] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Starch properties can be modified by mutating genes responsible for the synthesis of amylose and amylopectin in the endosperm. However, little is known about the effects of such targeted modifications on the overall starch biosynthesis pathway and broader metabolism. Here we investigated the effects of mutating the OsSBEIIb gene encoding starch branching enzyme IIb, which is required for amylopectin synthesis in the endosperm. As anticipated, homozygous mutant plants, in which OsSBEIIb was completely inactivated by abolishing the catalytic center and C-terminal regulatory domain, produced opaque seeds with depleted starch reserves. Amylose content in the mutant increased from 19.6 to 27.4% and resistant starch (RS) content increased from 0.2 to 17.2%. Many genes encoding isoforms of AGPase, soluble starch synthase, and other starch branching enzymes were up-regulated, either in their native tissues or in an ectopic manner, whereas genes encoding granule-bound starch synthase, debranching enzymes, pullulanase, and starch phosphorylases were largely down-regulated. There was a general increase in the accumulation of sugars, fatty acids, amino acids, and phytosterols in the mutant endosperm, suggesting that intermediates in the starch biosynthesis pathway increased flux through spillover pathways causing a profound impact on the accumulation of multiple primary and secondary metabolites. Our results provide insights into the broader implications of perturbing starch metabolism in rice endosperm and its impact on the whole plant, which will make it easier to predict the effect of metabolic engineering in cereals for nutritional improvement or the production of valuable metabolites.
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Affiliation(s)
- Can Baysal
- Department of Plant Production and Forestry Science, University of Lleida-Agrotecnio Center, 25198 Lleida, Spain
| | - Wenshu He
- Department of Plant Production and Forestry Science, University of Lleida-Agrotecnio Center, 25198 Lleida, Spain
| | - Margit Drapal
- Department of Biological Sciences, Royal Holloway University of London, TW20 0EX Egham, United Kingdom
| | - Gemma Villorbina
- Department of Chemistry, University of Lleida-Agrotecnio Center, 25198 Lleida, Spain
| | - Vicente Medina
- Department of Plant Production and Forestry Science, University of Lleida-Agrotecnio Center, 25198 Lleida, Spain
| | - Teresa Capell
- Department of Plant Production and Forestry Science, University of Lleida-Agrotecnio Center, 25198 Lleida, Spain
| | - Gurdev S Khush
- Department of Plant Sciences, University of California, Davis, CA 95616;
| | - Changfu Zhu
- Department of Plant Production and Forestry Science, University of Lleida-Agrotecnio Center, 25198 Lleida, Spain
| | - Paul D Fraser
- Department of Biological Sciences, Royal Holloway University of London, TW20 0EX Egham, United Kingdom
| | - Paul Christou
- Department of Plant Production and Forestry Science, University of Lleida-Agrotecnio Center, 25198 Lleida, Spain;
- Catalan Institute for Research and Advanced Studies (ICREA), 08010 Barcelona, Spain
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Chen Z, Lu Y, Feng L, Hao W, Li C, Yang Y, Fan X, Li Q, Zhang C, Liu Q. Genetic Dissection and Functional Differentiation of ALK a and ALK b, Two Natural Alleles of the ALK/SSIIa Gene, Responding to Low Gelatinization Temperature in Rice. RICE (NEW YORK, N.Y.) 2020; 13:39. [PMID: 32529332 PMCID: PMC7289932 DOI: 10.1186/s12284-020-00393-5] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2019] [Accepted: 05/20/2020] [Indexed: 05/23/2023]
Abstract
BACKGROUND ALK is the key gene controlling rice gelatinization temperature (GT), which is closely associated with the eating and cooking quality (ECQ) in rice (Oryza sativa L.). To date, at least three ALK alleles are thought to be responsible for the diversity of GT among rice cultivars. The ALKc/SSIIai allele with high activity of the soluble starch synthase IIa (SSIIa) controls high GT, but the accurate functional difference between ALKa and ALKb alleles, both controlling low GT, is not clearly elucidated. Thus, we generated rice near-isogenic lines (NILs) by introducing different ALK alleles into the japonica cultivar Nipponbare (Nip) to clarify the discrepant effects of the two low-GT ALK alleles. RESULTS The results showed that the function of two low-GT alleles (ALKa and ALKb) was different, and a much lower GT was observed in NIL(ALKb) rice grains compared with that of Nip(ALKa). Moreover, the starches of NIL(ALKb) grains had a higher degree of branching, higher setback, consistence and higher cool pasting viscosity than those of Nip(ALKa). The lower expression level of ALKb, compared with ALKa, resulted in depleted intermediate chains and increased short chains of amylopectin, thus affected the thermal and pasting properties of NILs' grains. Also, the data revealed both low-GT alleles were mainly found in temperate japonica, but more ALKb was found in other subpopulations such as indica as compared to ALKa. CONCLUSIONS Overall, all the results suggested that the function between two low-GT alleles was different, and the distribution of ALKb was much wider than that of ALKa among the subpopulations of cultivated rice.
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Affiliation(s)
- Zhuanzhuan Chen
- State Key Laboratory of Hybrid Rice, Jiangsu Key Laboratory of Crop Genomics and Molecular Breeding, Jiangsu Key Laboratory of Crop Genetics and Physiology, Yangzhou University, Yangzhou, 225009, China
- Key Laboratory of Plant Functional Genomics of the Ministry of Education / Jiangsu Co-Innovation Center for Modern Production Technology of Grain Crops, College of Agriculture, Yangzhou University, Yangzhou, 225009, China
| | - Yan Lu
- Key Laboratory of Plant Functional Genomics of the Ministry of Education / Jiangsu Co-Innovation Center for Modern Production Technology of Grain Crops, College of Agriculture, Yangzhou University, Yangzhou, 225009, China
| | - Linhao Feng
- State Key Laboratory of Hybrid Rice, Jiangsu Key Laboratory of Crop Genomics and Molecular Breeding, Jiangsu Key Laboratory of Crop Genetics and Physiology, Yangzhou University, Yangzhou, 225009, China
| | - Weizhuo Hao
- State Key Laboratory of Hybrid Rice, Jiangsu Key Laboratory of Crop Genomics and Molecular Breeding, Jiangsu Key Laboratory of Crop Genetics and Physiology, Yangzhou University, Yangzhou, 225009, China
| | - Chuang Li
- State Key Laboratory of Hybrid Rice, Jiangsu Key Laboratory of Crop Genomics and Molecular Breeding, Jiangsu Key Laboratory of Crop Genetics and Physiology, Yangzhou University, Yangzhou, 225009, China
| | - Yong Yang
- State Key Laboratory of Hybrid Rice, Jiangsu Key Laboratory of Crop Genomics and Molecular Breeding, Jiangsu Key Laboratory of Crop Genetics and Physiology, Yangzhou University, Yangzhou, 225009, China
| | - Xiaolei Fan
- Key Laboratory of Plant Functional Genomics of the Ministry of Education / Jiangsu Co-Innovation Center for Modern Production Technology of Grain Crops, College of Agriculture, Yangzhou University, Yangzhou, 225009, China
| | - Qianfeng Li
- Key Laboratory of Plant Functional Genomics of the Ministry of Education / Jiangsu Co-Innovation Center for Modern Production Technology of Grain Crops, College of Agriculture, Yangzhou University, Yangzhou, 225009, China
| | - Changquan Zhang
- State Key Laboratory of Hybrid Rice, Jiangsu Key Laboratory of Crop Genomics and Molecular Breeding, Jiangsu Key Laboratory of Crop Genetics and Physiology, Yangzhou University, Yangzhou, 225009, China.
- Key Laboratory of Plant Functional Genomics of the Ministry of Education / Jiangsu Co-Innovation Center for Modern Production Technology of Grain Crops, College of Agriculture, Yangzhou University, Yangzhou, 225009, China.
| | - Qiaoquan Liu
- State Key Laboratory of Hybrid Rice, Jiangsu Key Laboratory of Crop Genomics and Molecular Breeding, Jiangsu Key Laboratory of Crop Genetics and Physiology, Yangzhou University, Yangzhou, 225009, China.
- Key Laboratory of Plant Functional Genomics of the Ministry of Education / Jiangsu Co-Innovation Center for Modern Production Technology of Grain Crops, College of Agriculture, Yangzhou University, Yangzhou, 225009, China.
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12
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Starch Components, Starch Properties and Appearance Quality of Opaque Kernels from Rice Mutants. Molecules 2019; 24:molecules24244580. [PMID: 31847303 PMCID: PMC6943482 DOI: 10.3390/molecules24244580] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2019] [Revised: 12/08/2019] [Accepted: 12/11/2019] [Indexed: 01/05/2023] Open
Abstract
Rice mutants with altered starch components and properties are important genetic resources in rice breeding programmes. In this study, 44 mutants with altered starch components were screened from 135 rice mutants with opaque kernels using a starch–iodine absorption spectrum method, and nine mutants from them were further selected for investigating their starch properties and kernel appearance quality. The results showed that the iodine absorption spectrum parameters, OD620, OD620/550, and λmax, could reflect the changes of starch components in rice mutants, and had significantly positive relationships with amylose content and negative relationships with the proportion of short branch-chains of amylopectin. The endosperm starches from nine mutants all showed A-type crystalline structure and similar short-range ordered structure, but had different relative crystallinities. The changes of starch components in mutants not only resulted in the different gelatinization properties of starch but also changed the appearance quality of brown rice kernels. This study provided abundant genetic plants for studying the molecular mechanism of starch synthesis and the quality regulation of rice kernels.
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13
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Anh TTT, Xuan TD, Huong CT, Dat TD. Phenotypic Performance of Rice ( Oryza sativa L .) Populations Induced by the MNU Mutant on the Adaptive Characteristics. ACTA ACUST UNITED AC 2019. [DOI: 10.18052/www.scipress.com/jhpr.5.13] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Mutation is an impressive method to induce potent characteristics in rice breeding. Evaluation on the phenotypic perfomance in mutant populations is important to examine the effectiveness of mutation. In this study, two rice populations of MNU ((N-methyl-N-Nitrosourea) -induced mutants were used to evaluate their phenotypes. The results showed that all of varieties and mutants expressed their ability to adapt with new environment condition via phenotypic expression. Grain yield of them ranged from 6.18 to 10.70 tons/ha. In general population S/TB performed their best characters. The distribution of related traits to grain yield and amylose content were also different from each population. It was observed that mutants expressed better characters than their parents. This study provided general information on phenotype of rice mutants and varieties in new environmental condition and revealed better adaptive characteristics of rice mutants. Findings of this study confirmed the the efficacy of MNU in rice breeding.
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14
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Crofts N, Iizuka Y, Abe N, Miura S, Kikuchi K, Matsushima R, Fujita N. Rice Mutants Lacking Starch Synthase I or Branching Enzyme IIb Activity Altered Starch Biosynthetic Protein Complexes. FRONTIERS IN PLANT SCIENCE 2018; 9:1817. [PMID: 30581451 PMCID: PMC6292963 DOI: 10.3389/fpls.2018.01817] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2018] [Accepted: 11/22/2018] [Indexed: 05/21/2023]
Abstract
Amylopectin, the major component of starch, is synthesized by synergistic activity of multiple isozymes of starch synthases (SSs) and branching enzymes (BEs). The frequency and length of amylopectin branches determine the functionality of starch. In the rice endosperm, BEIIb generates short side chains of amylopectin and SSI elongates those branches, which can be further elongated by SSIIa. Absence of these enzymes greatly affects amylopectin structure. SSI, SSIIa, and BEIIb associate with each other and with other starch biosynthetic enzymes although SSIIa is low activity in japonica rice. The aim of the current study was to understand how the activity of starch biosynthetic enzyme complexes is compensated in the absence of SSI or BEIIb, and whether the compensatory effects are different in the absence of BEIIb or in the presence of inactive BEIIb. Interactions between starch biosynthetic enzymes were analyzed using one ss1 null mutant and two be2b japonica rice mutants (a mutant producing inactive BEIIb and a mutant that did not produce BEIIb). Soluble proteins extracted from the developing rice seeds were separated by gel filtration chromatography. In the absence of BEIIb activity, BEIIa was eluted in a broad molecular weight range (60-700 kDa). BEIIa in the wild-type was eluted with a mass below 300 kDa. Further, majority of inactive BEIIb co-eluted with SSI, SSIIa, and BEI, in a mass fraction over 700 kDa, whereas only small amounts of these isozymes were found in the wild-type. Compared with the be2b lines, the ss1 mutant showed subtle differences in protein profiles, but the amounts of SSIIa, SSIVb, and BEI in the over-700-kDa fraction were elevated. Immunoprecipitation revealed reduced association of SSIIa and BEIIb in the ss1 mutant, while the association of BEIIb with SSI, SSIIa, SSIVb, BEI, and BEIIa were more pronounced in the be2b mutant that produced inactive BEIIb enzyme. Mass spectrometry and western blotting revealed that SSI, SSIIa, SSIIIa, BEI, BEIIa, starch phosphorylase 1, and pullulanase were bound to the starch granules in the be2b mutants, but not in the wild-type and ss1 mutant. These results will aid the understanding of the mechanism of amylopectin biosynthesis.
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Affiliation(s)
- Naoko Crofts
- Department of Biological Production, Faculty of Bioresource Sciences, Akita Prefectural University, Akita, Japan
| | - Yuriko Iizuka
- Department of Biological Production, Faculty of Bioresource Sciences, Akita Prefectural University, Akita, Japan
| | - Natsuko Abe
- Department of Biological Production, Faculty of Bioresource Sciences, Akita Prefectural University, Akita, Japan
| | - Satoko Miura
- Department of Biological Production, Faculty of Bioresource Sciences, Akita Prefectural University, Akita, Japan
| | - Kana Kikuchi
- Department of Biological Production, Faculty of Bioresource Sciences, Akita Prefectural University, Akita, Japan
| | - Ryo Matsushima
- Institute of Plant Science and Resources, Okayama University, Okayama, Japan
| | - Naoko Fujita
- Department of Biological Production, Faculty of Bioresource Sciences, Akita Prefectural University, Akita, Japan
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15
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Nakata M, Miyashita T, Kimura R, Nakata Y, Takagi H, Kuroda M, Yamaguchi T, Umemoto T, Yamakawa H. MutMapPlus identified novel mutant alleles of a rice starch branching enzyme IIb gene for fine-tuning of cooked rice texture. PLANT BIOTECHNOLOGY JOURNAL 2018; 16:111-123. [PMID: 28499068 PMCID: PMC5785365 DOI: 10.1111/pbi.12753] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2017] [Revised: 03/23/2017] [Accepted: 05/01/2017] [Indexed: 05/07/2023]
Abstract
Physicochemical properties of storage starch largely determine rice grain quality and food characteristics. Therefore, modification of starch property is effective to fine-tune cooked rice textures. To obtain new resources with modified starch property as breeding materials, we screened a mutant population of a japonica cultivar Nipponbare and found two independent mutant lines, altered gelatinization (age)1 and age2, with moderate changes in starch gelatinization property. A combination of conventional genetic analyses and the latest mapping method, MutMapPlus, revealed that both of these lines harbour novel independent mutant alleles of starch branching enzyme IIb (BEIIb) gene. In age1, amino acid substitution of Met-723 to Lys completely abolished BEIIb enzyme activity without significant reduction in its protein level. A transposon insertion in an intron of BEIIb gene reduced BEIIb protein level and activity in age2. Production of a series of the mutant lines by combining age alleles and indica-type starch synthase IIa allele established stepwise alteration of the physicochemical properties of starch including apparent amylose content, thermal property, digestibility by α-amylase and branched structures of amylopectin. Consistent with the alteration of starch properties, the results of a sensory evaluation test demonstrated that warm cooked rice of the mutants showed a variety of textures without marked reduction in overall palatability. These results suggest that a series of the mutant lines are capable of manipulation of cooked rice textures.
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Affiliation(s)
- Masaru Nakata
- Division of Crop DevelopmentCentral Region Agricultural Research CenterNational Agriculture and Food Research Organization (NARO)JoetsuJapan
| | - Tomomi Miyashita
- Division of Crop DevelopmentCentral Region Agricultural Research CenterNational Agriculture and Food Research Organization (NARO)JoetsuJapan
| | - Rieko Kimura
- Division of Crop DevelopmentCentral Region Agricultural Research CenterNational Agriculture and Food Research Organization (NARO)JoetsuJapan
| | - Yuriko Nakata
- Division of Crop DevelopmentCentral Region Agricultural Research CenterNational Agriculture and Food Research Organization (NARO)JoetsuJapan
| | - Hiroki Takagi
- Department of Bioproduction ScienceIshikawa Prefectural UniversityNonoichiJapan
| | - Masaharu Kuroda
- Division of Crop DevelopmentCentral Region Agricultural Research CenterNational Agriculture and Food Research Organization (NARO)JoetsuJapan
| | - Takeshi Yamaguchi
- Division of Crop DevelopmentCentral Region Agricultural Research CenterNational Agriculture and Food Research Organization (NARO)JoetsuJapan
| | - Takayuki Umemoto
- Institute of Crop ScienceNational Agriculture and Food Research Organization (NARO)TsukubaJapan
| | - Hiromoto Yamakawa
- Division of Crop DevelopmentCentral Region Agricultural Research CenterNational Agriculture and Food Research Organization (NARO)JoetsuJapan
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16
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Affiliation(s)
- Yasunori Nakamura
- Akita Natural Science Laboratory; Tennoh, Katagami, Akita Japan
- Faculty of Bioresource Sciences; Akita Prefectural University; Shimoshinjo-Nakano, Akita Japan
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17
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Wang J, Hu P, Chen Z, Liu Q, Wei C. Progress in High-Amylose Cereal Crops through Inactivation of Starch Branching Enzymes. FRONTIERS IN PLANT SCIENCE 2017; 8:469. [PMID: 28421099 PMCID: PMC5379859 DOI: 10.3389/fpls.2017.00469] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2016] [Accepted: 03/17/2017] [Indexed: 05/18/2023]
Abstract
High-amylose cereal starches provide many health benefits for humans. The inhibition or mutation of starch branching enzyme (SBE) genes is an effective method to develop high-amylose cereal crops. This review summarizes the development of high-amylose cereal crops through the inactivation of one or more SBE isoforms or combination with other genes. This review also reveals the causes of increase in amylose content in high-amylose crops. A series of changes, including amylopectin structure, crystalline structure, thermal properties, and hydrolysis properties, occurs as amylose content increases. The different morphological starch granules nominated as heterogeneous starch granules or differently stained starch granules are detected in high-amylose cereal crops. Detailed studies on four heterogeneous starch granules in high-amylose rice, which is developed by antisense RNA inhibition of SBEI/IIb, indicate that granules with different morphologies possess various molecular structures and physicochemical and functional properties. This variation diversifies their applications in food and non-food industries. However, current knowledge regarding how these heterogeneous starch granules form and why they exhibit regional distribution in endosperm remain largely unknown.
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Affiliation(s)
- Juan Wang
- Jiangsu Key Laboratory of Crop Genetics and Physiology/Co-Innovation Center for Modern Production Technology of Grain Crops, Yangzhou UniversityYangzhou, China
- Joint International Research Laboratory of Agriculture and Agri-Product Safety, Yangzhou UniversityYangzhou, China
| | - Pan Hu
- Jiangsu Key Laboratory of Crop Genetics and Physiology/Co-Innovation Center for Modern Production Technology of Grain Crops, Yangzhou UniversityYangzhou, China
- Joint International Research Laboratory of Agriculture and Agri-Product Safety, Yangzhou UniversityYangzhou, China
| | - Zichun Chen
- Jiangsu Key Laboratory of Crop Genetics and Physiology/Co-Innovation Center for Modern Production Technology of Grain Crops, Yangzhou UniversityYangzhou, China
- Joint International Research Laboratory of Agriculture and Agri-Product Safety, Yangzhou UniversityYangzhou, China
| | - Qiaoquan Liu
- Jiangsu Key Laboratory of Crop Genetics and Physiology/Co-Innovation Center for Modern Production Technology of Grain Crops, Yangzhou UniversityYangzhou, China
- Joint International Research Laboratory of Agriculture and Agri-Product Safety, Yangzhou UniversityYangzhou, China
| | - Cunxu Wei
- Jiangsu Key Laboratory of Crop Genetics and Physiology/Co-Innovation Center for Modern Production Technology of Grain Crops, Yangzhou UniversityYangzhou, China
- Joint International Research Laboratory of Agriculture and Agri-Product Safety, Yangzhou UniversityYangzhou, China
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18
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Wang K, Henry RJ, Gilbert RG. Causal Relations Among Starch Biosynthesis, Structure, and Properties. ACTA ACUST UNITED AC 2014. [DOI: 10.1007/s40362-014-0016-0] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
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19
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Matsushima R, Maekawa M, Kusano M, Kondo H, Fujita N, Kawagoe Y, Sakamoto W. Amyloplast-localized SUBSTANDARD STARCH GRAIN4 protein influences the size of starch grains in rice endosperm. PLANT PHYSIOLOGY 2014; 164:623-36. [PMID: 24335509 PMCID: PMC3912094 DOI: 10.1104/pp.113.229591] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2013] [Accepted: 12/13/2013] [Indexed: 05/18/2023]
Abstract
Starch is a biologically and commercially important polymer of glucose and is synthesized to form starch grains (SGs) inside amyloplasts. Cereal endosperm accumulates starch to levels that are more than 90% of the total weight, and most of the intracellular space is occupied by SGs. The size of SGs differs depending on the plant species and is one of the most important factors for industrial applications of starch. However, the molecular machinery that regulates the size of SGs is unknown. In this study, we report a novel rice (Oryza sativa) mutant called substandard starch grain4 (ssg4) that develops enlarged SGs in the endosperm. Enlargement of SGs in ssg4 was also observed in other starch-accumulating tissues such as pollen grains, root caps, and young pericarps. The SSG4 gene was identified by map-based cloning. SSG4 encodes a protein that contains 2,135 amino acid residues and an amino-terminal amyloplast-targeted sequence. SSG4 contains a domain of unknown function490 that is conserved from bacteria to higher plants. Domain of unknown function490-containing proteins with lengths greater than 2,000 amino acid residues are predominant in photosynthetic organisms such as cyanobacteria and higher plants but are minor in proteobacteria. The results of this study suggest that SSG4 is a novel protein that influences the size of SGs. SSG4 will be a useful molecular tool for future starch breeding and biotechnology.
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20
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Matsushima R, Yamashita J, Kariyama S, Enomoto T, Sakamoto W. A Phylogenetic Re-evaluation of Morphological Variations of Starch Grains among Poaceae Species. J Appl Glycosci (1999) 2013. [DOI: 10.5458/jag.jag.jag-2012_006] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022] Open
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21
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Pandey MK, Rani NS, Madhav MS, Sundaram RM, Varaprasad GS, Sivaranjani AKP, Bohra A, Kumar GR, Kumar A. Different isoforms of starch-synthesizing enzymes controlling amylose and amylopectin content in rice (Oryza sativa L.). Biotechnol Adv 2012; 30:1697-706. [PMID: 22960619 DOI: 10.1016/j.biotechadv.2012.08.011] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2011] [Revised: 08/23/2012] [Accepted: 08/25/2012] [Indexed: 11/27/2022]
Abstract
Starch, composed of amylose and amylopectin, greatly influences rice cooking and textural quality, which in turn is controlled by various isoforms of several enzymes. Activity of one or more isoforms of starch-synthesizing enzymes results in various forms of starch structure based on the amylopectin chain length and average external, internal and core chain length distribution and hence results in varying physicochemical and cooking quality. Since the synthesis of starch is highly complex, it is crucial but essential to understand its biosynthetic pathway, starch structure and effects on the physicochemical properties that control eating and cooking quality, and alongside conduct research on gene/QTL mapping for use in marker-assisted selection (MAS) with a view to improve and select cultivars with most desirable range and class of rice starch properties. This article presents the updates on current understanding of the coordination among various enzymes/isoforms towards rice starch synthesis in endosperm and their effect on rice grain physicochemical, cooking and eating qualities. The efforts in identifying regions responsible for these enzymes by mapping the gene/QTLs have provided a glimpse on their association with physicochemical and cooking properties of rice and, hence, improvement is possible by modifying the allelic pattern, resulting in down or nil regulation of a particular enzyme. The clear understanding of the tissue specific coordination between enzyme isoforms and their subsequent effect in controlling eating and cooking properties will enhance the chances to manipulate them for getting desired range of amylose content (AC) and gelatinization temperature (GT) in improved cultivars through combining desired alleles through MAS.
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Affiliation(s)
- Manish K Pandey
- Crop Improvement Section, Directorate of Rice Research (DRR), Rajendranagar, Hyderabad 500030, India.
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22
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Nakamura Y, Utsumi Y, Sawada T, Aihara S, Utsumi C, Yoshida M, Kitamura S. Characterization of the reactions of starch branching enzymes from rice endosperm. PLANT & CELL PHYSIOLOGY 2010; 51:776-94. [PMID: 20305271 DOI: 10.1093/pcp/pcq035] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
To our knowledge the present paper shows for the first time the kinetic parameters of all the three starch branching enzyme (BE) isozymes, BEI, BEIIa and BEIIb, from rice with both amylopectin and synthetic amylose as glucan substrate. The activities of these BE isozymes with a linear glucan amylose decreased with a decrease in the molar size of amylose, and no activities of BEIIa and BEIIb were found when the degree of polymerization (DP) of amylose was lower than at least 80, whereas BEI had an activity with amylose of a DP higher than approximately 50. Detailed analyses of debranched products from BE reactions revealed the distinct chain length preferences of the individual BE isozymes. BEIIb almost exclusively transferred chains of DP7 and DP6 while BEIIa formed a wide range of short chains of DP6 to around DP15 from outer chains of amylopectin and amylose. On the other hand, BEI formed a variety of short chains and intermediate chains of a DP <or=40 by attacking not only outer chains but also inner chains of branched glucan while BEIIa or BEIIb could only scarcely or could not attack inner chains, respectively. The comprehensive in vitro studies revealed different enzymatic characteristics of the three BE isozymes and give a new insight into the distinct roles of individual BE isozymes in amylopectin biosynthesis in the endosperm. Based on these results, the functional distinction and interaction of BE isozymes during amylopectin biosynthesis in cereal endosperm is discussed.
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Affiliation(s)
- Yasunori Nakamura
- Faculty of Bioresource Sciences, Akita Prefectural University, Akita-City, 010-0195 Japan.
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23
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Matsushima R, Maekawa M, Fujita N, Sakamoto W. A rapid, direct observation method to isolate mutants with defects in starch grain morphology in rice. PLANT & CELL PHYSIOLOGY 2010; 51:728-41. [PMID: 20360021 DOI: 10.1093/pcp/pcq040] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Starch forms transparent grains, referred to as starch grains (SGs), in amyloplasts. Despite the simple glucose polymer composition of starch, SGs exhibit different morphologies depending on plant species, especially in the endosperm of the Poaceae family. This study reports a novel method for preparing thin sections of endosperm without chemical fixation or resin embedding that allowed us to visualize subcellular SGs clearly. Using this method, we observed the SG morphologies of >5,000 mutagenized rice seeds and were able to isolate mutants in which SGs were morphologically altered. In five mutants, named ssg (substandard starch grain), increased numbers of small SGs (ssg1-ssg3), enlarged SGs (ssg4) and abnormal interior structures of SGs (ssg5) were observed. Amylopectin chain length distribution analysis and identification of the mutated gene suggested a possible allelic relationship between ssg1, ssg2, ssg3 and the previously isolated amylose-extender (ae) mutants, while ssg4 and ssg5 seemed to be novel mutants. Compared with conventional observation methods, the methods developed here are more effective for obtaining fine images of subcellular SGs and are suitable for the observation of a large number of samples.
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Affiliation(s)
- Ryo Matsushima
- Institute of Plant Science and Resources, Okayama University, Kurashiki, 710-0046 Japan.
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24
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Sawada Y, Kuwahara A, Nagano M, Narisawa T, Sakata A, Saito K, Hirai MY. Omics-based approaches to methionine side chain elongation in Arabidopsis: characterization of the genes encoding methylthioalkylmalate isomerase and methylthioalkylmalate dehydrogenase. PLANT & CELL PHYSIOLOGY 2009; 50:1062-74. [PMID: 19493961 DOI: 10.1093/pcp/pcp058] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Glucosinolates (GSLs) are secondary metabolites in Brassicaceae plants synthesized from amino acids. Methionine-derived GSLs (Met-GSLs) with diverse side chains of various lengths are the major GSLs in Arabidopsis. Methionine chain elongation enzymes are responsible for variations in chain length in Met-GSL biosynthesis. The genes encoding methionine chain elongation enzymes are considered to have been recruited from the leucine biosynthetic pathway in the course of evolution. Among them, the genes encoding methylthioalkylmalate synthases and aminotransferases have been identified; however, the remaining genes that encode methylthioalkylmalate isomerase (MAM-I) and methylthioalkylmalate dehydro-genase (MAM-D) remain to be identified. In a previous study based on transcriptome co-expression analysis, we identified candidate genes for the large subunit of MAM-I and MAM-D. In this study, we confirmed their predicted functions by targeted GSL analysis of the knockout mutants, and named the respective genes MAM-IL1/AtleuC1 and MAM-D1/AtIMD1. Metabolic profiling of the knockout mutants of methionine chain elongation enzymes, conducted by means of widely targeted metabolomics, implied that these enzymes have roles in controlling metabolism from methionine to primary and methionine-related secondary metabolites. As shown here, an omics-based approach is an efficient strategy for the functional elucidation of genes involved in metabolism.
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Affiliation(s)
- Yuji Sawada
- RIKEN Plant Science Center, Yokohama, Kanagawa, Japan
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25
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Satoh H, Shibahara K, Tokunaga T, Nishi A, Tasaki M, Hwang SK, Okita TW, Kaneko N, Fujita N, Yoshida M, Hosaka Y, Sato A, Utsumi Y, Ohdan T, Nakamura Y. Mutation of the plastidial alpha-glucan phosphorylase gene in rice affects the synthesis and structure of starch in the endosperm. THE PLANT CELL 2008; 20:1833-49. [PMID: 18621947 PMCID: PMC2518224 DOI: 10.1105/tpc.107.054007] [Citation(s) in RCA: 185] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2007] [Revised: 06/02/2008] [Accepted: 06/23/2008] [Indexed: 05/18/2023]
Abstract
Plastidial phosphorylase (Pho1) accounts for approximately 96% of the total phosphorylase activity in developing rice (Oryza sativa) seeds. From mutant stocks induced by N-methyl-N-nitrosourea treatment, we identified plants with mutations in the Pho1 gene that are deficient in Pho1. Strikingly, the size of mature seeds and the starch content in these mutants showed considerable variation, ranging from shrunken to pseudonormal. The loss of Pho1 caused smaller starch granules to accumulate and modified the amylopectin structure. Variation in the morphological and biochemical phenotype of individual seeds was common to all 15 pho1-independent homozygous mutant lines studied, indicating that this phenotype was caused solely by the genetic defect. The phenotype of the pho1 mutation was temperature dependent. While the mutant plants grown at 30 degrees C produced mainly plump seeds at maturity, most of the seeds from plants grown at 20 degrees C were shrunken, with a significant proportion showing severe reduction in starch accumulation. These results strongly suggest that Pho1 plays a crucial role in starch biosynthesis in rice endosperm at low temperatures and that one or more other factors can complement the function of Pho1 at high temperatures.
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Affiliation(s)
- Hikaru Satoh
- Plant Genetic Resources, Institute of Genetic Resources, Faculty of Agriculture, Kyushu University, Fukuoka 812-8581, Japan.
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Suzuki T, Eiguchi M, Kumamaru T, Satoh H, Matsusaka H, Moriguchi K, Nagato Y, Kurata N. MNU-induced mutant pools and high performance TILLING enable finding of any gene mutation in rice. Mol Genet Genomics 2007; 279:213-23. [PMID: 17952471 DOI: 10.1007/s00438-007-0293-2] [Citation(s) in RCA: 102] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2007] [Revised: 09/12/2007] [Accepted: 09/17/2007] [Indexed: 02/07/2023]
Abstract
Mutant populations are indispensable genetic resources for functional genomics in all organisms. However, suitable rice mutant populations, induced either by chemicals or irradiation still have been rarely developed to date. To produce mutant pools and to launch a search system for rice gene mutations, we developed mutant populations of Oryza sativa japonica cv. Taichung 65, by treating single zygotic cells with N-methyl-N-nitrosourea (MNU). Mutagenesis in single zygotes can create mutations at a high frequency and rarely forms chimeric plants. A modified TILLING system using non-labeled primers and fast capillary gel electrophoresis was applied for high-throughput detection of single nucleotide substitution mutations. The mutation rate of an M(2) mutant population was calculated as 7.4 x 10(-6) per nucleotide representing one mutation in every 135 kb genome sequence. One can expect 7.4 single nucleotide substitution mutations in every 1 kb of gene region when using 1,000 M(2) mutant lines. The mutations were very evenly distributed over the regions examined. These results indicate that our rice mutant population generated by MNU-mutagenesis could be a promising resource for identifying mutations in any gene of rice. The modified TILLING method also proved very efficient and convenient in screening the mutant population.
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Affiliation(s)
- Tadzunu Suzuki
- Genetic Strains Research Center, National Institute of Genetics, 1111 Yata, Mishima, Shizuoka, 411-8540, Japan
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Utsumi Y, Nakamura Y. Structural and enzymatic characterization of the isoamylase1 homo-oligomer and the isoamylase1-isoamylase2 hetero-oligomer from rice endosperm. PLANTA 2006; 225:75-87. [PMID: 16953433 DOI: 10.1007/s00425-006-0331-z] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2006] [Accepted: 05/11/2006] [Indexed: 05/11/2023]
Abstract
The present study established that there are two distinct polymeric forms of isoamylase1 (ISA1) in rice endosperm: presumably a homo-pentamer of ISA1 and a hetero-hexamer composed of five ISA1 and one ISA2. The molecular sizes of the homo- and hetero-oligomers, which could be fractionated by hydrophobic chromatography, were approximately 420-480 and 510-550 kDa, respectively. The hetero-oligomer exhibited higher affinities for various branched polyglucans, especially for phytoglycogen, which had a K(m) value that was approximately 12 times lower relative to that with the homo-oligomer, although no marked differences were found in chain preferences for debranching of amylopectin and phytoglycogen between these forms. The hetero-oligomer was active even when incubated at 50 degrees C for 10 min, while the homo-multimer was completely inactivated at 40 degrees C in 10 min. When the ISA1 homo-oligomer was incubated with the ISA2 protein expressed in Escherichia coli and applied onto a nondenature polyacrylamide gel, additional debranching activity bands which were specific for the purified ISA1-ISA2 preparation were also detected, indicating that ISA1 and ISA2 combine to form a hetero-oligomer. These results suggest that the hetero-oligomer plays a predominant role in the amylopectin biosynthesis in rice endosperm although the homo-oligomer can complement the function of the hetero-oligomer at least to some extent.
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Affiliation(s)
- Yoshinori Utsumi
- Department of Biological Production, Akita Prefectural University, 241-7 Kaidobata-Nishi, Shimoshinjyo-Nakano, Akita-city, 010-0195, Japan
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Suzuki K, Nakamura S, Satoh H, Ohtsubo K. Relationship between Chain-length Distributions of Waxy Rice Amylopectins and Physical Properties of Rice Grains. J Appl Glycosci (1999) 2006. [DOI: 10.5458/jag.53.227] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022] Open
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Ohdan T, Francisco PB, Sawada T, Hirose T, Terao T, Satoh H, Nakamura Y. Expression profiling of genes involved in starch synthesis in sink and source organs of rice. JOURNAL OF EXPERIMENTAL BOTANY 2005; 56:3229-44. [PMID: 16275672 DOI: 10.1093/jxb/eri292] [Citation(s) in RCA: 265] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
A comprehensive analysis of the transcript levels of genes which encode starch-synthesis enzymes is fundamental for the assessment of the function of each enzyme and the regulatory mechanism for starch biosynthesis in source and sink organs. Using quantitative real-time RT-PCR, an examination was made of the expression profiles of 27 rice genes encoding six classes of enzymes, i.e. ADPglucose pyrophosphorylase (AGPase), starch synthase, starch branching enzyme, starch debranching enzyme, starch phosphorylase, and disproportionating enzyme in developing seeds and leaves. The modes of gene expression were tissue- and developmental stage-specific. Four patterns of expression in the seed were identified: group 1 genes, which are expressed very early in grain formation and are presumed to be involved in the construction of fundamental cell machineries, de novo synthesis of glucan primers, and initiation of starch granules; group 2 genes, which are highly expressed throughout endosperm development; group 3 genes, which have transcripts that are low at the onset but which rise steeply at the start of starch synthesis in the endosperm and are thought to play essential roles in endosperm starch synthesis; and group 4 genes, which are expressed scantly, mainly at the onset of grain development, and might be involved in synthesis of starch in the pericarp. The methodology also revealed that the defect in the cytosolic AGPase small subunit2b (AGPS2b) transcription from the AGPS2 gene in endosperm sharply enhanced the expressions of endosperm and leaf plastidial AGPS1, the endosperm cytosolic AGPase large subunit2 (AGPL2), and the leaf plastidial AGPL1.
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Affiliation(s)
- Takashi Ohdan
- Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency (JST), 4-1-8, Honcho, Kawaguchi, Saitama 332-0012, Japan
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Kawagoe Y, Kubo A, Satoh H, Takaiwa F, Nakamura Y. Roles of isoamylase and ADP-glucose pyrophosphorylase in starch granule synthesis in rice endosperm. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2005; 42:164-74. [PMID: 15807780 DOI: 10.1111/j.1365-313x.2005.02367.x] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Amyloplast-targeted green fluorescent protein (GFP) was used to monitor amyloplast division and starch granule synthesis in the developing endosperm of transgenic rice. Two classical starch mutants, sugary and shrunken, contain reduced activities of isoamylase1 (ISA1) and cytosolic ADP-glucose pyrophosphorylase, respectively. Dividing amyloplasts in the wild-type and shrunken endosperms contained starch granules, whereas those in sugary endosperm did not contain detectable granules, suggesting that ISA1 plays a role in granule synthesis at the initiation step. The transition from phytoglycogen to sugary-amylopectin was gradual in the boundary region between the inner and outer endosperms of sugary. These results suggest that the synthesis of sugary-amylopectin and phytoglycogen involved a stochastic process and that ISA1 activity plays a critical role in the stochastic process in starch synthesis in rice endosperm. The reduction of cytosolic ADP-glucose pyrophosphorylase activity in shrunken endosperm did not inhibit granule initiation but severely restrained the subsequent enlargement of granules. The shrunken endosperm often developed pleomorphic amyloplasts containing a large number of underdeveloped granules or a large cluster of small grains of amyloplasts, each containing a simple-type starch granule. Although constriction-type divisions of amyloplasts were much more frequent, budding-type divisions were also found in the shrunken endosperm. We show that monitoring GFP in developing amyloplasts was an effective means of evaluating the roles of enzymes involved in starch granule synthesis in the rice endosperm.
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Affiliation(s)
- Yasushi Kawagoe
- Department of Plant Biotechnology, National Institute of Agrobiological Sciences, 2-1-2 Kannondai, Tsukuba 305 8602, Japan
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Tanaka N, Fujita N, Nishi A, Satoh H, Hosaka Y, Ugaki M, Kawasaki S, Nakamura Y. The structure of starch can be manipulated by changing the expression levels of starch branching enzyme IIb in rice endosperm. PLANT BIOTECHNOLOGY JOURNAL 2004; 2:507-16. [PMID: 17147623 DOI: 10.1111/j.1467-7652.2004.00097.x] [Citation(s) in RCA: 82] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
When the starch branching enzyme IIb (BEIIb) gene was introduced into a BEIIb-defective mutant, the resulting transgenic rice plants showed a wide range of BEIIb activity and the fine structure of their amylopectins showed considerable variation despite having the two other BE isoforms, BEI and BEIIa, in their endosperm at the same levels as in the wild-type. The properties of the starch granules, such as their gelatinization behaviour, morphology and X-ray diffraction pattern, also changed dramatically depending on the level of BEIIb activity, even when this was either slightly lower or higher than that of the wild-type. The over-expression of BEIIb resulted in the accumulation of excessive branched, water-soluble polysaccharides instead of amylopectin. These results imply that the manipulation of BEIIb activity is an effective strategy for the generation of novel starches for use in foodstuffs and industrial applications.
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Affiliation(s)
- Naoki Tanaka
- National Institute of Agrobiological Sciences, Kannondai, Tsukuba, Ibaraki 305-8602, Japan
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Nakamura Y. A Note on the Metabolic System for the Synthesis of the Tandem-Cluster Structure of Amylopectin in Rice Endosperm. J Appl Glycosci (1999) 2004. [DOI: 10.5458/jag.51.259] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022] Open
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Satoh H, Nishi A, Yamashita K, Takemoto Y, Tanaka Y, Hosaka Y, Sakurai A, Fujita N, Nakamura Y. Starch-branching enzyme I-deficient mutation specifically affects the structure and properties of starch in rice endosperm. PLANT PHYSIOLOGY 2003; 133:1111-21. [PMID: 14526120 PMCID: PMC281607 DOI: 10.1104/pp.103.021527] [Citation(s) in RCA: 181] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2003] [Revised: 03/03/2003] [Accepted: 07/10/2003] [Indexed: 05/18/2023]
Abstract
We have isolated a starch mutant that was deficient in starch-branching enzyme I (BEI) from the endosperm mutant stocks of rice (Oryza sativa) induced by the treatment of fertilized egg cells with N-methyl-N-nitrosourea. The deficiency of BEI in this mutant was controlled by a single recessive gene, tentatively designated as starch-branching enzyme mutant 1 (sbe1). The mutant endosperm exhibited the normal phenotype and contained the same amount of starch as the wild type. However, the mutation apparently altered the fine structure of amylopectin. The mutant amylopectin was characterized by significant decrease in both long chains with degree of polymerization (DP) > or = 37 and short chains with DP 12 to 21, marked increase in short chains with DP < or = 10 (A chains), and slight increase in intermediate chains with DP 24 to 34, suggesting that BEI specifically synthesizes B1 and B2-3 chains. The endosperm starch from the sbe1 mutant had a lower onset concentration for urea gelatinization and a lower onset temperature for thermo-gelatinization compared with the wild type, indicating that the genetic modification of amylopectin fine structure is responsible for changes in physicochemical properties of sbe1 starch.
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Affiliation(s)
- Hikaru Satoh
- Faculty of Agriculture, Kyushu University, Hakozaki, Higashi-ku, Fukuoka 812-8581, Japan.
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