Introduction of sense and antisense cDNA for branching enzyme in the amylose-free potato mutant leads to physico-chemical changes in the starch

Flipse, E.; Suurs, L.C.J.M.; Keetels, C.J.A.M.; Koßmann, Jens; Jacobsen, E.; Visser, Richard G. F.

doi:10.1007/bf00620049

Cited by 60 publications

(32 citation statements)

References 38 publications

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“…This phenomenon was first reported for chalcone synthase in petunia (Napoli et al, 1990;van der Krol et al, 1990), and there have since been many other examples reported in the literature (e.g. Vanlerberghe et al, 1994;Brusslan and Tobin, 1995;Paul et al, 1995;Flipse et al, 1996). Three nonmutually exclusive mechanisms have been proposed to explain the occurrence of cosense suppression: (a) alterations in chromatin structure, (b) changes in methylation of promoter sequences, and (c) posttranscriptional mechanism(s) resulting in the degradation of both introduced and endogenous mRNA (Flavell, 1994).…”

Section: )supporting

confidence: 52%

NADP-Malate Dehydrogenase in the C4 Plant Flaveria bidentis (Cosense Suppression of Activity in Mesophyll and Bundle-Sheath Cells and Consequences for Photosynthesis)

1997

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ACT 2601, Australia (R.T.F., A.R.A.)Haveria bidentis, a C, dicot, was transformed with sorghum (a monocot) cDNA clones encoding NADP-malate dehydrogenase (NADP-MDH; EC 1 .I .I 3 2 ) driven by the cauliflower mosaic virus 35s promoter. Although these constructs were designed for overexpression, many transformants contained between 5 and 50% of normal NADP-MDH activity, presumably by cosense suppression of the native gene. The activities of a range of other photosynthetic enzymes were unaffected. Rates of photosynthesis i n plants with less than about 10% of normal activity were reduced at high light and at high [COZI, but were unaffected at low light or at [CO,] below about 150 pL 1-'. The large decrease in maximum activity of NADP-MDH was accompanied by an increase in the activation state of the enzyme. However, the activation state was unaffected in plants with 50% of normal activity. Metabolic flux control analysis of plants with a range of activities demonstrates that this enzyme is not important in regulating the steady-state flux through C, photosynthesis in F. bidentis. Cosense suppression of gene expression was similarly effective in both the mesophyll and bundle-sheath cells. Photosynthesis of plants with very low activity of NADP-MDH in the bundle-sheath cells was only slightly inhibited, suggesting that the presence of the enzyme in this compartment is not essential for supporting maximum rates of photosynthesis.

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Section: )supporting

confidence: 52%

NADP-Malate Dehydrogenase in the C4 Plant Flaveria bidentis (Cosense Suppression of Activity in Mesophyll and Bundle-Sheath Cells and Consequences for Photosynthesis)

1997

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“…Presently, the processes influencing the size of starch granules are poorly investigated [9]; however, there are data pointing to a possible participation of the enzyme BE I in the regulation of these processes [10]. It is worth noting that the average size of starch granules in the tubers of potato transformed with an antisense construction of BE I considerably increased [25]. These data suggest that changes in the activity of BE I enzyme can modify dimensions of starch gran ules in rolB and rolC plants of potato as compared with control material.…”

Section: Discussionmentioning

confidence: 99%

Agrobacterial rol genes modify thermodynamic and structural properties of starch in microtubers of transgenic potato

Aksenova

Wasserman

Сергеева

et al. 2010

Russ J Plant Physiol

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INTRODUCTIONTuber formation in potato is regulated by numerous external and internal factors with phytohormones being of special importance [1]. In order to investigate the hormonal control over tuber formation, some researchers used transformed potato plants expressing rolB and rolC genes of Agrobacterium rhizogenes [2]. Biochemical mechanism of the operation of rol trans genes remains debatable; however, it was shown that their role in higher plants resembles to the effect of phytohormones: auxins in case rolB and cytokinins in case rolC [3]. It is assumed that hormone like effect of rol genes may be related to their influence on the metabolism of auxins and cytokinins or to the changes in plant cell sensitivity to these phytohormones [3]. It was also shown that the intensity of the effect of rol genes on morphogenesis of potato plants greatly depends on the used promoter governing organospec ificity of gene expression [4].It order to investigate the effect of genes rolB and rolC on tuber formation, we used B33 class I patatin promoter, which ensured preferred expression of B33::rolC and B33::rolB in growing potato tubers [5]. These experiments showed that transgenes induced numerous morphological changes accompanied by changes in the activity of some enzymes of carbohy drate metabolism, the content of soluble sugars [6], and the number and size of starch granules [7]. The obtained data suggested that transgenes rolB and rolC might also modify qualitative characteristics of storage starch, which by volume and biological role is the Abstract-Wild type (WT) plants of potato (Solanum tuberosum L.) and their transgenic forms carrying agro bacterial genes rolB or rolC under the control of B33 class I patatin promoter were cultured in vitro on MS medium with 2% sucrose in a controlled climate chamber at 16 h illumination and 22°C. These plants were used as a source of single node stem cuttings, which were cultured in darkness on the same medium supple mented with 8% sucrose. The tubers formed on them were used for determination of the structure of native starch using the methods of differential scanning microcalorimetry (DSC), X ray scattering, and scanning electron microscopy. It was found that, in starch from the tubers of rolB plants, the temperature of crystalline lamella melting was lower and their thickness was less than in WT potato. In tubers of rolC plants, starch dif fered from starch in WT plants by a higher melting temperature, considerably reduced melting enthalpy, and a greater thickness of crystalline lamellae. Deconvolution of DSC thermogram makes it possible to interpret the melting of starch from the tubers of rolC plants as the melting of two independent crystalline structures with melting temperatures of 65.0 and 69.8°C. Electron microscopic examination confirmed the earlier obtained data indicating that, in the tubers of rolC plants, starch granules are smaller and in the tubers of rolB plants larger than in WT plants. Possible ways of influence of rol transgenes on structural properties of star...

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“…It has also been shown that the lack of one isoform of BE in peas resulted in a reduced level of starch (4,43). On the other hand, it has been reported that inhibition of the activity of one BE isoform in potatoes did not significantly affect the content and structure of starch (7). Recently, we demonstrated that BE catalyzes not only simple branching but also new reactions, such as the cyclization of glucan and transfer of multibranched glucan in vitro (48)(49)(50).…”

Section: Discussionmentioning

confidence: 99%

Characterization of a gene cluster for glycogen biosynthesis and a heterotetrameric ADP-glucose pyrophosphorylase from Bacillus stearothermophilus

et al. 1997

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.27]): the sequences share 42 to 70% and 20 to 30% identities with AGP, respectively. Purification of GlgC and GlgD indicated that AGP is an ␣ 2 ␤ 2 -type heterotetrameric enzyme consisting of these two proteins. AGP did not seem to be an allosteric enzyme, although the activities of most bacterial AGPs are known to be allosterically controlled. GlgC protein had AGP activity without GlgD protein, but its activity was lower than that of the heterotetrameric enzyme. The GlgA (485 aa) and GlgP (798 aa) proteins were shown to be glycogen synthase (EC 2.4.1.21) and glycogen phosphorylase (EC 2.4.1.1), respectively. We constructed plasmids harboring these five genes (glgBCDAP) and assayed glycogen production by a strain carrying each of the derivative plasmids on which the genes were mutated one by one. Glycogen metabolism in B. stearothermophilus is discussed on the basis of these results.Glycogen is the major reserve polysaccharide in bacteria. Its biosynthesis from glucose-1-phosphate is catalyzed by at least three enzymes (30): ADP-glucose pyrophosphorylase (AGP [EC 2.7.7.27]), glycogen synthase (EC 2.4.1.21), and branching enzyme (BE [EC 2.4.1.18]). In Escherichia coli, the genes encoding these enzymes are organized in two adjacent operons, glgBX and glgCAP (38). glgB, glgC, and glgA encode BE, AGP, and glycogen synthase, respectively. It has been shown that glgX and glgP encode debranching enzyme and glycogen phosphorylase, respectively, and that neither is needed for glycogen synthesis (38,53,54). The product of glgS has also been shown to be involved in glycogen synthesis, although its function is unclear (14). The regulation of glycogen synthesis is achieved by controlling the expression of glg genes and through the allosteric control of AGP activity (14,30,34,35,37).AGPs have been isolated from various bacterial species, and all bacterial AGPs known to date are homotetrameric enzymes (19,32). Most of these enzymes are allosterically activated by glycolytic intermediates, such as fructose-1,6-bisphosphate, and are inhibited by AMP, ADP, and/or orthophosphate (30, 34). On the other hand, plant AGP involved in starch synthesis is an ␣ 2 ␤ 2 -type heterotetrameric enzyme (31). The subunits of plant AGP, which are called small and large subunits, are homologous to each other and are speculated to be derived from a single ancestral protein (46). The major activator and inhibitor for plant AGPs are 3-phosphoglycerate, the primary CO 2 fixation product of oxygenic photosynthesis, and orthophosphate, respectively (31).Little is known about the regulation of glycogen synthesis and the characteristics of AGP from gram-positive bacteria. In Bacillus subtilis, the genes for glycogen synthesis have been shown to be clustered in one operon, glgBCDAP (18). However, the enzymatic activities of encoded proteins were not analyzed. In particular, the function of glgD, which is partially homologous to glgC, is unclear. Since glgD has been found only in this species, it may be important in glycogen metabolism in the bacteria.We p...

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Introduction of sense and antisense cDNA for branching enzyme in the amylose-free potato mutant leads to physico-chemical changes in the starch

Cited by 60 publications

References 38 publications

NADP-Malate Dehydrogenase in the C4 Plant Flaveria bidentis (Cosense Suppression of Activity in Mesophyll and Bundle-Sheath Cells and Consequences for Photosynthesis)

NADP-Malate Dehydrogenase in the C4 Plant Flaveria bidentis (Cosense Suppression of Activity in Mesophyll and Bundle-Sheath Cells and Consequences for Photosynthesis)

Agrobacterial rol genes modify thermodynamic and structural properties of starch in microtubers of transgenic potato

Characterization of a gene cluster for glycogen biosynthesis and a heterotetrameric ADP-glucose pyrophosphorylase from Bacillus stearothermophilus

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