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《Gene》1998,216(2):233-243
Starch branching enzymes (SBE) which catalyse the formation of α-1,6-glucan linkages are of crucial importance for the quantity and quality of starch synthesized in plants. In maize (Zea mays L.), three SBE isoforms (SBEI, IIa and IIb) have been identified and shown to exhibit differential expression patterns. As a first step toward understanding the regulatory mechanisms controlling their expression, we isolated and sequenced a maize genomic DNA (−2190 to +5929) which contains the entire coding region of SBEI (Sbe1) as well as 5′-and 3′-flanking sequences. Using this clone, we established a complete genomic organization of the maize Sbe1 gene. The transcribed region consists of 14 exons and 13 introns, distributed over 5.7 kb. A consensus TATA-box and a G-box containing a perfect palindromic sequence, CCACGTGG, were found in the 5′-flanking region. Genomic Southern blot analysis indicated that two Sbe1 genes with divergent 5′-flanking sequences exist in the maize genome, suggesting the possibility that they are differentially regulated. A chimeric construct containing the 5′-flanking region of Sbe1 (−2190 to +27) fused to the β-glucuronidase gene (pKG101) showed promoter activity after it was introduced into maize endosperm suspension cells by particle bombardment. 相似文献
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Identification of Mutator insertional mutants of starch-branching enzyme 2a in corn 总被引:14,自引:0,他引:14
Blauth SL Yao Y Klucinec JD Shannon JC Thompson DB Guilitinan MJ 《Plant physiology》2001,125(3):1396-1405
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Aytug Tuncel Kendall R. Corbin Jennifer Ahn‐Jarvis Suzanne Harris Erica Hawkins Mark A. Smedley Wendy Harwood Frederick J. Warren Nicola J. Patron Alison M. Smith 《Plant biotechnology journal》2019,17(12):2259-2271
We investigated whether Cas9‐mediated mutagenesis of starch‐branching enzymes (SBEs) in tetraploid potatoes could generate tuber starches with a range of distinct properties. Constructs containing the Cas9 gene and sgRNAs targeting SBE1, SBE2 or both genes were introduced by Agrobacterium‐mediated transformation or by PEG‐mediated delivery into protoplasts. Outcomes included lines with mutations in all or only some of the homoeoalleles of SBE genes and lines in which homoeoalleles carried several different mutations. DNA delivery into protoplasts resulted in mutants with no detectable Cas9 gene, suggesting the absence of foreign DNA. Selected mutants with starch granule abnormalities had reductions in tuber SBE1 and/or SBE2 protein that were broadly in line with expectations from genotype analysis. Strong reduction in both SBE isoforms created an extreme starch phenotype, as reported previously for low‐SBE potato tubers. HPLC‐SEC and 1H NMR revealed a decrease in short amylopectin chains, an increase in long chains and a large reduction in branching frequency relative to wild‐type starch. Mutants with strong reductions in SBE2 protein alone had near‐normal amylopectin chain‐length distributions and only small reductions in branching frequency. However, starch granule initiation was enormously increased: cells contained many granules of <4 μm and granules with multiple hila. Thus, large reductions in both SBEs reduce amylopectin branching during granule growth, whereas reduction in SBE2 alone primarily affects numbers of starch granule initiations. Our results demonstrate that Cas9‐mediated mutagenesis of SBE genes has the potential to generate new, potentially valuable starch properties without integration of foreign DNA into the genome. 相似文献
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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 总被引:2,自引:0,他引:2
Regina A Kosar-Hashemi B Li Z Pedler A Mukai Y Yamamoto M Gale K Sharp PJ Morell MK Rahman S 《Planta》2005,222(5):899-909
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. 相似文献
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Modification of starch metabolism in transgenic Arabidopsis thaliana increases plant biomass and triples oilseed production
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Fushan Liu Qianru Zhao Noel Mano Zaheer Ahmed Felix Nitschke Yinqqi Cai Kent D. Chapman Martin Steup Ian J. Tetlow Michael J. Emes 《Plant biotechnology journal》2016,14(3):976-985
We have identified a novel means to achieve substantially increased vegetative biomass and oilseed production in the model plant Arabidopsis thaliana. Endogenous isoforms of starch branching enzyme (SBE) were substituted by either one of the endosperm‐expressed maize (Zea mays L.) branching isozymes, ZmSBEI or ZmSBEIIb. Transformants were compared with the starch‐free background and with the wild‐type plants. Each of the maize‐derived SBEs restored starch biosynthesis but both morphology and structure of starch particles were altered. Altered starch metabolism in the transformants is associated with enhanced biomass formation and more‐than‐trebled oilseed production while maintaining seed oil quality. Enhanced oilseed production is primarily due to an increased number of siliques per plant whereas oil content and seed number per silique are essentially unchanged or even modestly decreased. Introduction of cereal starch branching isozymes into oilseed plants represents a potentially useful strategy to increase biomass and oilseed production in related crops and manipulate the structure and properties of leaf starch. 相似文献
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Ami Takeuchi Mariko Ohnuma Hiroshi Teramura Kenji Asano Takahiro Noda Hiroaki Kusano Koji Tamura Hiroaki Shimada 《Plant Biotechnology》2021,38(3):345
The potato tuber starch trait is changed depending on the composition of amylose and amylopectin. The amount of amylopectin is determined by the activity of the starch branching enzymes SBE1, SBE2, and SBE3 in potato. SBE3, a homolog of rice BEI, is a major gene that is abundant in tubers. In this study, we created mutants of the potato SBE3 gene using CRISPR/Cas9 attached to the translation enhancer dMac3. Potato has a tetraploid genome, and a four-allele mutant of the SBE3 gene is desired. Mutations in the SBE3 gene were found in 89 of 126 transformants of potato plants. Among these mutants, 10 lines contained four mutant SBE3 genes, indicating that 8% efficiency of target mutagenesis was achieved. These mutants grew normally, similar to the wild-type plant, and yielded sufficient amounts of tubers. The potato starch in these tubers was similar to that of the rice BEI mutant. Western blot analysis revealed the defective production of SBE3 in the mutant tubers, suggesting that these transformants were loss-of-function mutants of SBE3. 相似文献
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应用RNA干扰技术降低玉米支链淀粉含量 总被引:25,自引:0,他引:25
为了调控玉米淀粉的生物合成过程,克隆了玉米淀粉分支酶(starch branching enzymes,SBE)基因,构建高效的siRNA表达体系,通过花粉管通道法将其导入玉米自交系.PCR扩增和Southern杂交结果证明,目的基因已被整合到基因组中,且能够遗传.Northern杂交分析表明,该目的基因在转基因植株中能正常转录并导致内源SBE mRNA含量下降.对转基因植株淀粉分支酶活性和淀粉含量测定结果表明,分支酶活性明显地低于对照,相差最多的低85%;总淀粉含量与对照之间基本没有差异,但直链淀粉的含量提高了约50%. 相似文献
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Ahmed Regina Pierre Berbezy Behjat Kosar‐Hashemi Suzhi Li Mark Cmiel Oscar Larroque Anthony R. Bird Steve M. Swain Colin Cavanagh Stephen A. Jobling Zhongyi Li Matthew Morell 《Plant biotechnology journal》2015,13(9):1276-1286
Resistant starch (RS), a type of dietary fibre, plays an important role in human health; however, the content of RS in most modern processed starchy foods is low. Cereal starch, when structurally manipulated through a modified starch biosynthetic pathway to greatly increase the amylose content, could be an important food source of RS. Transgenic studies have previously revealed the requirement of simultaneous down‐regulation of two starch branching enzyme (SBE) II isoforms both located on the long arm of chromosome 2, namely SBEIIa and SBEIIb, to elevate the amylose content in wheat from ~25% to ~75%. The current study revealed close proximity of genes encoding SBEIIa and SBEIIb isoforms in wheat with a genetic distance of 0.5 cM on chromosome 2B. A series of deletion and single nucleotide polymorphism (SNP) loss of function alleles in SBEIIa, SBEIIb or both was isolated from two different wheat populations. A breeding strategy to combine deletions and SNPs generated wheat genotypes with altered expression levels of SBEIIa and SBEIIb, elevating the amylose content to an unprecedented ~85%, with a marked concomitant increase in RS content. Biochemical assays were used to confirm the complete absence in the grain of expression of SBEIIa from all three genomes in combination with the absence of SBEIIb from one of the genomes. 相似文献
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ADPglucose: α-1,4-glucan α-4-glucosyltransferases (starch synthetases) from leaves of Vitis vinifera and leaves and kernels of Zea mays were chromatographed on DEAE-cellulose columns. One form of the enzyme was present in grape leaves having activity both in the presence and absence of primer. Two forms were present in both leaves and kernels of maize. The second peak of activity in maize leaves and the first peak in maize kernels synthesized a polyglucan in the absence of primer. A peak of branching enzyme (Q-enzyme) occurred between the two starch synthetase peaks with both tissues. When fractions containing starch synthetase and branching enzyme were added to the first leaf starch synthetase peak, up to 100-fold activation of the unprimed reaction occurred. Branching enzyme did not stimulate the unprimed activity of the first kernel peak and no branching enzyme could be detected in this peak. The unprimed product was a branched polyglucan with mainly α-1,4-links. 相似文献
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ZmHox: a novel class of maize homeobox genes 总被引:2,自引:0,他引:2
Bettina Klinge Bärbel Überlacker Christian Korfhage Wolfgang Werr 《Plant molecular biology》1996,30(3):439-453
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淀粉分支酶(starch branching enzyme, SBE)是淀粉合成的限速酶。为了进一步研究SBEⅡb沉默对玉米生长及直链淀粉合成的影响,克隆了玉米(Zea mays)淀粉分支酶SBEⅡb基因片段,构建了SBEⅡb的发卡结构表达载体pTFU-SBEⅡb hairpin,用农杆菌介导法将其导入玉米HiⅡ幼胚中,经除草剂筛选获得了194株转化再生植株,其中4株结实,获得转基因种子35粒。T1代植株经PCR及试纸条检测获得3株阳性材料,半定量RT-PCR结果得出SBEⅡb的表达量降低,推断出基因表达水平降低对直链淀粉的合成具有正效应。 相似文献
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Feibing Wang Yuxiu Ye Yuan Niu Faxiang Wan Bo Qi Xinhong Chen Qing Zhou Boqing Chen 《Physiology and Molecular Biology of Plants》2016,22(4):497-506
A plastidic ATP/ADP transporter (AATP) is responsible for importing ATP from the cytosol into plastids. Increasing the ATP supply is a potential way to facilitate anabolic synthesis in heterotrophic plastids of plants. In this work, a gene encoding the AATP protein, named SlAATP, was successfully isolated from tomato. Expression of SlAATP was induced by exogenous sucrose treatment in tomato. The coding region of SlAATP was cloned into a binary vector under the control of 35S promoter and then transformed into Arabidopsis to obtain transgenic plants. Constitutive expression of SlAATP significantly increased the starch accumulation in the transgenic plants. Real-time quantitative PCR (qRT-PCR) analysis showed that constitutive expression of StAATP up-regulated the expression of phosphoglucomutase (AtPGM), ADP-glucose pyrophosphorylase (AtAGPase), granule-bound starch synthase (AtGBSS I and AtGBSS II), soluble starch synthases (AtSSS I, AtSSS II, AtSSS III and AtSSS IV) and starch branching enzyme (AtSBE I and AtSBE II) genes involved in starch biosynthesis in the transgenic Arabidopsis plants. Meanwhile, enzymatic analyses indicated that the major enzymes (AGPase, GBSS, SSS and SBE) involved in the starch biosynthesis exhibited higher activities in the transgenic plants compared to the wild-type (WT). These findings suggest that SlAATP may improve starch content of Arabidopsis by up-regulating the expression of the related genes and increasing the activities of the major enzymes invovled in starch biosynthesis. The manipulation of SlAATP expression might be used for increasing starch accumulation of plants in the future. 相似文献