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Miao H, Sun P, Liu Q, Liu J, Jia C, Zhao D, Xu B, Jin Z. Molecular identification of the key starch branching enzyme-encoding gene SBE2.3 and its interacting transcription factors in banana fruits. HORTICULTURE RESEARCH 2020; 7:101. [PMID: 32637129 PMCID: PMC7326998 DOI: 10.1038/s41438-020-0325-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2019] [Revised: 04/21/2020] [Accepted: 04/25/2020] [Indexed: 06/01/2023]
Abstract
Starch branching enzyme (SBE) has rarely been studied in common starchy banana fruits. For the first time, we report here the molecular characterization of seven SBE (MaSBE) and six SBE (MbSBE) genes in the banana A- and B-genomes, respectively, which could be classified into three distinct subfamilies according to genome-wide identification. Systematic transcriptomic analysis revealed that six MaSBEs and six MbSBEs were expressed in the developing banana fruits of two different genotypes, BaXi Jiao (BX, AAA) and Fen Jiao (FJ, AAB), among which MaSBE2.3 and MbSBE2.3 were highly expressed. Transient silencing of MaSBE2.3 expression in banana fruit discs led to a significant decrease in its transcription, which coincides with significant reductions in total starch and amylopectin contents compared to those of empty vector controls. The suggested functional role of MaSBE2.3 in banana fruit development was corroborated by its transient overexpression in banana fruit discs, which led to significant enhancements in total starch and amylopectin contents. A number of transcription factors, including three auxin response factors (ARF2/12/24) and two MYBs (MYB3/308), that interact with the MaSBE2.3 promoter were identified by yeast one-hybrid library assays. Among these ARFs and MYBs, MaARF2/MaMYB308 and MaARF12/MaARF24/MaMYB3 were demonstrated via a luciferase reporter system to upregulate and downregulate the expression of MaSBE2.3, respectively.
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Affiliation(s)
- Hongxia Miao
- Key Laboratory of Tropical Crop Biotechnology, Ministry of Agriculture, Institute of Tropical Bioscience and Biotechnology, Chinese Academy of Tropical Agricultural Sciences, 571101 Haikou, People’s Republic of China
| | - Peiguang Sun
- Key Laboratory of Genetic Improvement of Bananas, Haikou Experimental Station, Chinese Academy of Tropical Agricultural Sciences, 571101 Haikou, Hainan Province People’s Republic of China
| | - Qing Liu
- Commonwealth Scientific and Industrial Research Organization Agriculture and Food, Canberra, ACT 2601 Australia
| | - Juhua Liu
- Key Laboratory of Tropical Crop Biotechnology, Ministry of Agriculture, Institute of Tropical Bioscience and Biotechnology, Chinese Academy of Tropical Agricultural Sciences, 571101 Haikou, People’s Republic of China
| | - Caihong Jia
- Key Laboratory of Tropical Crop Biotechnology, Ministry of Agriculture, Institute of Tropical Bioscience and Biotechnology, Chinese Academy of Tropical Agricultural Sciences, 571101 Haikou, People’s Republic of China
| | - Dongfang Zhao
- Key Laboratory of Tropical Crop Biotechnology, Ministry of Agriculture, Institute of Tropical Bioscience and Biotechnology, Chinese Academy of Tropical Agricultural Sciences, 571101 Haikou, People’s Republic of China
| | - Biyu Xu
- Key Laboratory of Tropical Crop Biotechnology, Ministry of Agriculture, Institute of Tropical Bioscience and Biotechnology, Chinese Academy of Tropical Agricultural Sciences, 571101 Haikou, People’s Republic of China
| | - Zhiqiang Jin
- Key Laboratory of Tropical Crop Biotechnology, Ministry of Agriculture, Institute of Tropical Bioscience and Biotechnology, Chinese Academy of Tropical Agricultural Sciences, 571101 Haikou, People’s Republic of China
- College of Horticulture, Nanjing Agricultural University, 210095 Nanjing, People’s Republic of China
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Van Harsselaar JK, Lorenz J, Senning M, Sonnewald U, Sonnewald S. Genome-wide analysis of starch metabolism genes in potato (Solanum tuberosum L.). BMC Genomics 2017; 18:37. [PMID: 28056783 PMCID: PMC5217216 DOI: 10.1186/s12864-016-3381-z] [Citation(s) in RCA: 62] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2016] [Accepted: 12/06/2016] [Indexed: 12/11/2022] Open
Abstract
Background Starch is the principle constituent of potato tubers and is of considerable importance for food and non-food applications. Its metabolism has been subject of extensive research over the past decades. Despite its importance, a description of the complete inventory of genes involved in starch metabolism and their genome organization in potato plants is still missing. Moreover, mechanisms regulating the expression of starch genes in leaves and tubers remain elusive with regard to differences between transitory and storage starch metabolism, respectively. This study aimed at identifying and mapping the complete set of potato starch genes, and to study their expression pattern in leaves and tubers using different sets of transcriptome data. Moreover, we wanted to uncover transcription factors co-regulated with starch accumulation in tubers in order to get insight into the regulation of starch metabolism. Results We identified 77 genomic loci encoding enzymes involved in starch metabolism. Novel isoforms of many enzymes were found. Their analysis will help to elucidate mechanisms of starch biosynthesis and degradation. Expression analysis of starch genes led to the identification of tissue-specific isoenzymes suggesting differences in the transcriptional regulation of starch metabolism between potato leaf and tuber tissues. Selection of genes predominantly expressed in developing potato tubers and exhibiting an expression pattern indicative for a role in starch biosynthesis enabled the identification of possible transcriptional regulators of tuber starch biosynthesis by co-expression analysis. Conclusions This study provides the annotation of the complete set of starch metabolic genes in potato plants and their genomic localizations. Novel, so far undescribed, enzyme isoforms were revealed. Comparative transcriptome analysis enabled the identification of tuber- and leaf-specific isoforms of starch genes. This finding suggests distinct regulatory mechanisms in transitory and storage starch metabolism. Putative regulatory proteins of starch biosynthesis in potato tubers have been identified by co-expression and their expression was verified by quantitative RT-PCR. Electronic supplementary material The online version of this article (doi:10.1186/s12864-016-3381-z) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Jessica K Van Harsselaar
- Department of Biology, Division of Biochemistry, Friedrich-Alexander-University Erlangen-Nuremberg, Staudtstrasse 5, 91058, Erlangen, Germany
| | - Julia Lorenz
- Department of Biology, Division of Biochemistry, Friedrich-Alexander-University Erlangen-Nuremberg, Staudtstrasse 5, 91058, Erlangen, Germany
| | - Melanie Senning
- Department of Biology, Division of Biochemistry, Friedrich-Alexander-University Erlangen-Nuremberg, Staudtstrasse 5, 91058, Erlangen, Germany
| | - Uwe Sonnewald
- Department of Biology, Division of Biochemistry, Friedrich-Alexander-University Erlangen-Nuremberg, Staudtstrasse 5, 91058, Erlangen, Germany
| | - Sophia Sonnewald
- Department of Biology, Division of Biochemistry, Friedrich-Alexander-University Erlangen-Nuremberg, Staudtstrasse 5, 91058, Erlangen, Germany.
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Nougué O, Corbi J, Ball SG, Manicacci D, Tenaillon MI. Molecular evolution accompanying functional divergence of duplicated genes along the plant starch biosynthesis pathway. BMC Evol Biol 2014; 14:103. [PMID: 24884572 PMCID: PMC4041918 DOI: 10.1186/1471-2148-14-103] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2013] [Accepted: 05/02/2014] [Indexed: 12/15/2022] Open
Abstract
Background Starch is the main source of carbon storage in the Archaeplastida. The starch biosynthesis pathway (sbp) emerged from cytosolic glycogen metabolism shortly after plastid endosymbiosis and was redirected to the plastid stroma during the green lineage divergence. The SBP is a complex network of genes, most of which are members of large multigene families. While some gene duplications occurred in the Archaeplastida ancestor, most were generated during the sbp redirection process, and the remaining few paralogs were generated through compartmentalization or tissue specialization during the evolution of the land plants. In the present study, we tested models of duplicated gene evolution in order to understand the evolutionary forces that have led to the development of SBP in angiosperms. We combined phylogenetic analyses and tests on the rates of evolution along branches emerging from major duplication events in six gene families encoding sbp enzymes. Results We found evidence of positive selection along branches following cytosolic or plastidial specialization in two starch phosphorylases and identified numerous residues that exhibited changes in volume, polarity or charge. Starch synthases, branching and debranching enzymes functional specializations were also accompanied by accelerated evolution. However, none of the sites targeted by selection corresponded to known functional domains, catalytic or regulatory. Interestingly, among the 13 duplications tested, 7 exhibited evidence of positive selection in both branches emerging from the duplication, 2 in only one branch, and 4 in none of the branches. Conclusions The majority of duplications were followed by accelerated evolution targeting specific residues along both branches. This pattern was consistent with the optimization of the two sub-functions originally fulfilled by the ancestral gene before duplication. Our results thereby provide strong support to the so-called “Escape from Adaptive Conflict” (EAC) model. Because none of the residues targeted by selection occurred in characterized functional domains, we propose that enzyme specialization has occurred through subtle changes in affinity, activity or interaction with other enzymes in complex formation, while the basic function defined by the catalytic domain has been maintained.
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Affiliation(s)
| | | | | | - Domenica Manicacci
- University Paris-Sud, UMR 0320/UMR 8120 Génétique Végétale, Ferme du Moulon, F-91190 Gif-sur-Yvette, France.
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Chang JW, Li SC, Shih YC, Wang R, Chung PS, Ko YT. Molecular characterization of mungbean (Vigna radiata L.) starch branching enzyme I. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2010; 58:10437-10444. [PMID: 20822148 DOI: 10.1021/jf102129f] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Mungbean (Vigna radiata L. cv. Tainan no. 5) starch branching enzyme I (SBE, EC 2.4.1.18) cDNA, VrsbeI, was cloned, and its expression was characterized. Conserved regions of the family B SBE were used to amplify a full length cDNA of 2208 bp. Phylogeny was analyzed, and the partial 3D structure and functional features were predicted. Catalytic residues were identified in the (α/β)(8)-fold, and a unique loop from F365 to F376 between β3/α3 was located. Gene expression of VrsbeI in seeds during growth showed that the transcript appeared from week 1 and increased substantially at week 3-4. It was cloned into the pET30 vector and expressed in E. coli BL21(DE3) pLysS cells as a soluble recombinant protein. The affinity-purified recombinant VrSBEI exhibited a specific activity of 314.6 U/mg as an active enzyme with 114-fold activity enrichment from the crude extract.
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Affiliation(s)
- Jia-Wei Chang
- Department of Food Science, Biotechnology Division, School of Life Sciences, National Taiwan Ocean University, 2 Pei-Ning Road, Keelung 20224, Taiwan, ROC
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Regina A, Kosar-Hashemi B, Li Z, Pedler A, Mukai Y, Yamamoto M, Gale K, Sharp PJ, Morell MK, Rahman S. Starch branching enzyme IIb in wheat is expressed at low levels in the endosperm compared to other cereals and encoded at a non-syntenic locus. PLANTA 2005; 222:899-909. [PMID: 16172866 DOI: 10.1007/s00425-005-0032-z] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2005] [Accepted: 06/02/2005] [Indexed: 05/04/2023]
Abstract
Studies of maize starch branching enzyme mutants suggest that the amylose extender high amylose starch phenotype is a consequence of the lack of expression of the predominant starch branching enzyme II isoform expressed in the endosperm, SBEIIb. However, in wheat, the ratio of SBEIIb and SBEIIa expression are inversely related to the expression levels observed in maize and rice. Analysis of RNA at 15 days post anthesis suggests that there are about 4-fold more RNA for SBE IIa than for SBE IIb. The genes for SBE IIa and SBE IIb from wheat are distinguished in the size of the first three exons, allowing isoform-specific antibodies to be produced. These antibodies were used to demonstrate that in the soluble fraction, the amount of SBE IIa protein is two to three fold higher than SBIIb, whereas in the starch granule, there is two to three fold more SBE IIb protein amount than SBE IIa. In a further difference to maize and rice, the genes for SBE IIa and SBE IIb are both located on the long arm of chromosome 2 in wheat, in a position not expected from rice-maize-wheat synteny.
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MESH Headings
- 1,4-alpha-Glucan Branching Enzyme/genetics
- 1,4-alpha-Glucan Branching Enzyme/metabolism
- Amino Acid Sequence
- Base Sequence
- Chromosome Mapping
- DNA, Complementary/genetics
- DNA, Complementary/isolation & purification
- DNA, Plant/genetics
- DNA, Plant/isolation & purification
- Edible Grain/enzymology
- Edible Grain/genetics
- Gene Expression
- Genes, Plant
- In Situ Hybridization, Fluorescence
- Isoenzymes/genetics
- Isoenzymes/metabolism
- Molecular Sequence Data
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- RNA, Plant/genetics
- RNA, Plant/metabolism
- Recombinant Fusion Proteins/genetics
- Recombinant Fusion Proteins/metabolism
- Sequence Homology, Amino Acid
- Species Specificity
- Triticum/enzymology
- Triticum/genetics
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Affiliation(s)
- Ahmed Regina
- Commonwealth Scientific and Industrial Research Organisation, Plant Industry, P.O. Box 1600, Australian Capital Territory, 2601, Australia
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Eckermann N, Fettke J, Steup M. Identification of polysaccharide binding proteins by affinity electrophoresis in inhomogeneous polyacrylamide gels and subsequent SDS-PAGE/matrix-assisted laser desorption ionization-time of flight analysis. Anal Biochem 2002; 304:180-92. [PMID: 12009694 DOI: 10.1006/abio.2002.5628] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
A procedure that allows the identification of polysaccharide binding polypeptides is described. The method can be applied to proteins whose enzymatic activity is either unknown or cannot be identified unambiguously by activity-staining procedures and it has been used for very complex protein mixtures, such as crude extracts of plant organs. The procedure consists of three steps. First, an affinity polyacrylamide gel electrophoresis using an inhomogeneous polyacrylamide slab gel composed of two triangular parts, an upper gel lacking the ligand and a lower triangular gel containing an immobilized ligand, is performed. Proteins that interact with the ligand form bands that deviate from those of nonbinding proteins and can be detected by protein staining (or, if possible, by activity staining). Second, the bands containing the interacting proteins are excised, denatured, and subjected to SDS-PAGE using a slab gel. In the resulting protein pattern the target proteins cover most of the length of the gel piece applied to the SDS gel, whereas contaminating proteins appear as spots or narrow bands. Suitable regions of the target protein bands are selected for tryptic digestion. Third, the resulting peptides are analyzed by matrix-assisted laser desorption ionization-mass spectrometry followed by database research.
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Affiliation(s)
- Nora Eckermann
- Institute of Biochemistry and Biology, Plant Physiology, University of Potsdam, Karl-Liebknecht-Str. 24-25, Haus 20, D-14467 Golm, Germany
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Rydberg U, Andersson L, Andersson R, Aman P, Larsson H. Comparison of starch branching enzyme I and II from potato. EUROPEAN JOURNAL OF BIOCHEMISTRY 2001; 268:6140-5. [PMID: 11733008 DOI: 10.1046/j.0014-2956.2001.02568.x] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The in vitro activities of purified potato starch branching enzyme (SBE) I and II expressed in Escherichia coli were compared using several assay methods. With the starch-iodine method, it was found that SBE I was more active than SBE II on an amylose substrate, whereas SBE II was more active than SBE I on an amylopectin substrate. Both enzymes were stimulated by the presence of phosphate. On a substrate consisting of linear dextrins (chain length 8-200 glucose residues), no significant net increase in molecular mass was seen on gel-permeation chromatography after incubation with the enzymes. This indicates intrachain branching of the substrate. After debranching of the products, the majority of dextrins with a degree of polymerization (dp) greater than 60 were absent for SBE I and those with a dp greater than 70 for SBE II. To study the shorter chains, the debranched samples were also analysed by high-performance anion-exchange chromatography. The products of SBE I showed distinct populations at dp 11-12 and dp 29-30, whereas SBE II products had one, broader, population with a peak at dp 13-14. An accumulation of dp 6-7 chains was seen with both isoforms.
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Affiliation(s)
- U Rydberg
- Department of Plant Biology, Swedish University of Agricultural Sciences, Uppsala, Sweden
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8
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Rahman S, Regina A, Li Z, Mukai Y, Yamamoto M, Kosar-Hashemi B, Abrahams S, Morell MK. Comparison of starch-branching enzyme genes reveals evolutionary relationships among isoforms. Characterization of a gene for starch-branching enzyme IIa from the wheat genome donor Aegilops tauschii. PLANT PHYSIOLOGY 2001; 125:1314-24. [PMID: 11244112 PMCID: PMC65611 DOI: 10.1104/pp.125.3.1314] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2000] [Accepted: 12/20/2000] [Indexed: 05/20/2023]
Abstract
Genes and cDNAs for starch-branching enzyme II (SBEII) have been isolated from libraries constructed from Aegilops tauschii and wheat (Triticum aestivum) endosperm, respectively. One class of genes has been termed wSBEII-DA1 and encodes the N terminus reported for an SBEII from wheat endosperm. On the basis of phylogenetic comparisons with other branching enzyme sequences, wSBEII-DA1 is considered to be a member of the SBEIIa class. The wSBEII-DA1 gene consists of 22 exons with exons 4 to 21 being identical in length to the maize (Zea mays) SBEIIb gene, and the gene is located in the proximal region of the long arm of chromosome 2 at a locus designated sbe2a. RNA encoding SBEIIa can be detected in the endosperm from 6 d after flowering and is at its maximum level from 15 to 18 d after anthesis. Use of antibodies specific for SBEIIa demonstrated that this protein was present in both the soluble and granule bound fractions in developing wheat endosperm. We also report a cDNA sequence for SBEIIa that could arise by variant transcription/splicing. A second gene, termed wSBEII-DB1, was isolated and encodes an SBEII, which shows greater sequence identity with SBEIIb-type sequences than with SBEIIa-type sequences. Comparisons of SBEII gene structures among wheat, maize, and Arabidopsis indicate the lineage of the SBEII genes.
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Affiliation(s)
- S Rahman
- Commonwealth Scientific and Industrial Research Organization Plant Industry, P.O. Box 1600, Australian Capital Territory 2601, Australia.
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9
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Båga M, Nair RB, Repellin A, Scoles GJ, Chibbar RN. Isolation of a cDNA encoding a granule-bound 152-kilodalton starch-branching enzyme in wheat. PLANT PHYSIOLOGY 2000; 124:253-63. [PMID: 10982440 PMCID: PMC59140 DOI: 10.1104/pp.124.1.253] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2000] [Accepted: 05/17/2000] [Indexed: 05/21/2023]
Abstract
Screening of a wheat (Triticum aestivum) cDNA library for starch-branching enzyme I (SBEI) genes combined with 5'-rapid amplification of cDNA ends resulted in isolation of a 4,563-bp composite cDNA, Sbe1c. Based on sequence alignment to characterized SBEI cDNA clones isolated from plants, the SBEIc predicted from the cDNA sequence was produced with a transit peptide directing the polypeptide into plastids. Furthermore, the predicted mature form of SBEIc was much larger (152 kD) than previously characterized plant SBEI (80-100 kD) and contained a partial duplication of SBEI sequences. The first SBEI domain showed high amino acid similarity to a 74-kD wheat SBEI-like protein that is inactive as a branching enzyme when expressed in Escherichia coli. The second SBEI domain on SBEIc was identical in sequence to a functional 87-kD SBEI produced in the wheat endosperm. Immunoblot analysis of proteins produced in developing wheat kernels demonstrated that the 152-kD SBEIc was, in contrast to the 87- to 88-kD SBEI, preferentially associated with the starch granules. Proteins similar in size and recognized by wheat SBEI antibodies were also present in Triticum monococcum, Triticum tauschii, and Triticum turgidum subsp. durum.
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Affiliation(s)
- M Båga
- Plant Biotechnology Institute, National Research Council of Canada, 110 Gymnasium Place, Saskatoon, Saskatchewan, Canada S7N 0W9
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10
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Jobling SA, Schwall GP, Westcott RJ, Sidebottom CM, Debet M, Gidley MJ, Jeffcoat R, Safford R. A minor form of starch branching enzyme in potato (Solanum tuberosum L.) tubers has a major effect on starch structure: cloning and characterisation of multiple forms of SBE A. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 1999; 18:163-171. [PMID: 10363368 DOI: 10.1046/j.1365-313x.1999.00441.x] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Full length cDNAs encoding a second starch branching enzyme (SBE A) isoform have been isolated from potato tubers. The predicted protein has a molecular mass of 101 kDa including a transit peptide of 48 amino acids. Multiple forms of the SBE A gene exist which differ mainly in the length of a polyglutamic acid repeat at the C-terminus of the protein. Expression of the mature protein in Escherichia coli demonstrates that the gene encodes an active SBE. Northern analysis demonstrates that SBE A mRNA is expressed at very low levels in tubers but is the predominant isoform in leaves. This expression pattern was confirmed by Western analysis using isoform specific polyclonal antibodies raised against E. coli expressed SBE A. SBE A protein is found predominantly in the soluble phase of tuber extracts, indicating a stromal location within the plastid. Transgenic potato plants expressing an antisense SBE A RNA were generated in which almost complete reductions in SBE A were observed. SBE activity in the leaves of these plants was severely reduced, but tuber activity was largely unaffected. Even so, the composition and structure of tuber starch from these plants was greatly altered. The proportion of linear chains was not significantly increased but the average chain length of amylopectin was greater, resulting in an increase in apparent amylose content as judged by iodine binding. In addition, the starch had much higher levels of phosphorous.
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11
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Sun C, Sathish P, Ahlandsberg S, Jansson C. The two genes encoding starch-branching enzymes IIa and IIb are differentially expressed in barley. PLANT PHYSIOLOGY 1998; 118:37-49. [PMID: 9733524 PMCID: PMC34872 DOI: 10.1104/pp.118.1.37] [Citation(s) in RCA: 49] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/1998] [Accepted: 06/01/1998] [Indexed: 05/20/2023]
Abstract
The sbeIIa and sbeIIb genes, encoding starch-branching enzyme (SBE) IIa and SBEIIb in barley (Hordeum vulgare L.), have been isolated. The 5' portions of the two genes are strongly divergent, primarily due to the 2064-nucleotide-long intron 2 in sbeIIb. The sequence of this intron shows that it contains a retro-transposon-like element. Expression of sbeIIb but not sbeIIa was found to be endosperm specific. The temporal expression patterns for sbeIIa and sbeIIb were similar and peaked around 12 d after pollination. DNA gel-blot analysis demonstrated that sbeIIa and sbeIIb are both single-copy genes in the barley genome. By fluorescence in situ hybridization, the sbeIIa and sbeIIb genes were mapped to chromosomes 2 and 5, respectively. The cDNA clones for SBEIIa and SBEIIb were isolated and sequenced. The amino acid sequences of SBEIIa and SBEIIb were almost 80% identical. The major structural difference between the two enzymes was the presence of a 94-amino acid N-terminal extension in the SBEIIb precursor. The (beta/alpha)8-barrel topology of the alpha-amylase superfamily and the catalytic residues implicated in branching enzymes are conserved in both barley enzymes.
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MESH Headings
- 1,4-alpha-Glucan Branching Enzyme/genetics
- Amino Acid Sequence
- Base Sequence
- Chromosome Mapping
- Cloning, Molecular
- DNA Primers/genetics
- DNA, Complementary/genetics
- DNA, Plant/genetics
- Gene Expression Regulation, Developmental
- Gene Expression Regulation, Enzymologic
- Gene Expression Regulation, Plant
- Genes, Plant
- Hordeum/enzymology
- Hordeum/genetics
- Hordeum/growth & development
- In Situ Hybridization, Fluorescence
- Introns
- Isoenzymes/genetics
- Molecular Sequence Data
- Phylogeny
- Sequence Homology, Amino Acid
- Sequence Homology, Nucleic Acid
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Affiliation(s)
- C Sun
- Department of Biochemistry, The Arrhenius Laboratories, Stockholm University, S-106 91 Stockholm, Sweden
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12
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Preiss J, Sivak MN. Biochemistry, molecular biology and regulation of starch synthesis. GENETIC ENGINEERING 1998; 20:177-223. [PMID: 9666561 DOI: 10.1007/978-1-4899-1739-3_10] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Affiliation(s)
- J Preiss
- Department of Biochemistry, Michigan State University, East Lansing 48824, USA
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