Fructan Synthesis in Excised Barley Leaves (Identification of Two Sucrose-Sucrose Fructosyltransferases Induced by Light and Their Separation from Constitutive Invertases)

Simmen, Urs; Obenland, David; Boller, Thomas; Wiemken, Andres

doi:10.1104/pp.101.2.459

Cited by 75 publications

(62 citation statements)

References 22 publications

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“…We can only speculate about the advantages provided by fructan accumulation in the leaf growth zone. Undoubtedly, the rapidly expanding and differentiating ceils in this very delicate tissue are highly dependent on an uninterrupted, continuous supply of carbon and a source of energy, and fructan reserves are ideally suited for this function: fructans can be readily accumulated, particularly at low temperatures (Wagner et al, 1983;Wagner & Wiemken, 1989), where fructan biosynthetic enzymes show remark-ably high activities Simmen et al, 1993), and they can readily be remobilized (Wagner, Wiemken & Matile, 1986). Thus, fructans might buffer metabolism against potentially detrimental temporary shortages of carbon and energy supply, e.g.…”

Section: Discussionmentioning

confidence: 99%

Fructan and fructan‐metabolizing enzymes in the growth zone of barley leaves

ROTH¹,

Lüscher²,

SPRENGER³

et al. 1997

New Phytologist

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SUMMARYTo Study the role of fructan in leaf development of barley seedlings, fructan contents and the activities of enzymes involved in fructan metabolism were measured in segments of the third leaf at the stage of maximal growth. Fructans amounted to more than 10% of the d. wt in the growth zone at the base of the developing leaf and decreased sharply in the zone above. The specific activities of sucrose: sucrose 1-fructosyltransferase (1-SST) and sucrose: fructan 6-fructosyltransferase (6-SFT), two key enzymes in fructan synthesis, also peaked in the growth zone but decreased more slowly in the zone above. By contrast, the specific activities of invertase and fructan exohydrolase (FEH) were low in the growth zone at the leaf base and had their peak just above it. The specific activity of fructan: fructan 1-fructosyltransferase (1-FFT) was approx. constant over the whole leaf. These results indicate that transitory accumulation of fructans in the growth zone plays a key role in the development of barley leaves.

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Section: Discussionmentioning

confidence: 99%

Fructan and fructan‐metabolizing enzymes in the growth zone of barley leaves

ROTH¹,

Lüscher²,

SPRENGER³

et al. 1997

New Phytologist

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“…The low invertase activity (fructose production) was already saturated at 30 mM sucrose. It was not possible to establish whether this activity is a side reaction of the 1-SST or a contaminating invertase (Simmen et al, 1993).…”

Section: Product Formation After Incubation Of the Sections Obtained mentioning

confidence: 99%

“…Liliaceae have similar fructans but with a fructosyl chain also attached to the 6-position of the glucosyl residue (inulin neoseries). The fructans of many cereals such as barley have primarily β-2,6-linkages, and the enzyme responsible for these β-2-6 linkages, sucrose-fructan 6-fructosyltransferase (6-SFT), initially described as a 6-SST (Simmen et al, 1993), has been purified and cloned, and found to have a high sequence similarity with invertase . Interestingly, the enzyme 6-SFT appeared to have 1-kestose as its preferred fructosyl acceptor molecule (Duchateau et al, 1995 ;Sprenger et al, 1995), indicating that the first step in fructan biosynthesis of cereals also consists of the synthesis of 1-kestose by 1-SST .…”

Section: mentioning

confidence: 99%

Isolation of sucrose: sucrose 1‐fructosyltransferase (1‐SST) from barley (Hordeum vulgare)

et al. 2000

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The enzyme sucrose : sucrose 1-fructosyltransferase was partially purified from barley leaf growth zones. Four steps (ammonium sulphate precipitation and polyethylene glycol precipitation, followed by chromatography on Concanavalin A-sepharose and hydroxylapatite) yielded a 35-fold purification. The resulting preparation of 1-SST which still contained a number of different activities related to fructan metabolism, was subjected to preparative isoelectric focusing, and sections of the gel were analysed individually for 1-SST and related activities, using sucrose and 1-kestose as substrates. This procedure yielded a 196-fold purification and revealed the presence of two isozymes of 1-SST with pI values of 4.93 and 4.99, as determined by analytical isoelectric focusing of the corresponding fractions. Both isozymes produced glucose and 1-kestose when incubated with sucrose. In addition, small amounts of 6-kestose and tetrasaccharides were formed. In particular, one of the two 1-SST isozymes yielded fructose when incubated with 1-kestose, indicating that it also acts as a fructan exohydrolase. The other isozyme exhibited less fructan exohydrolase activity. Nystose was also degraded by the fructan exohydrolase activity but less than 1-kestose, whereas 6-kestose was not a substrate for the enzyme. Incubation of both 1-SSTs with different concentrations of sucrose showed that the enzyme was not saturated even at 500 mM. As for the barley sucrose : fructan 6-fructosyltransferase, both isozymes of 1-SST yielded two polypeptide bands of molecular weight 50 and 22 kDa upon sodium dodecylsulphate polyacrylamide gel electrophoresis, suggesting their close relationship to invertase (composed of two subunits of similar size), as previously reported for other plants.

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“…Penson & Cairns (1994) could not substantiate the ETP hypothesis in wheat. Instead, they and Simmen et al (1993) believe 6-kestose is synthesized anabolically from sucrose in cell-free enzyme preparations. Our studies (unpublished) of cell-free enzyme preparations from P. ampla, using sucrose as a substrate, show an early synthesis of 6-kestose, small but measurable amounts of 1-kestose, and trace amounts of bifurcose.…”

Section: Discussionmentioning

confidence: 99%

“…Bancal et al (1992) proposed that bifurcose might be an intermediate in the s^^nthesis of 6-kestose through an elongation-trimming pathway. Simmen et al, (1993) and Penson & Cairns (1994) demonstrated that 6-kestose is synthesized in barley and wheat directly from sucrose without other intermediates or the catabolism of bifurcose. 6-Kestose accumulated early with 1-kestose and bifurcose in cell-free preparations using sucrose as the substrate.…”

Section: Introductionmentioning

confidence: 99%

Fructan oligomers in Poa ampla

Chatterton¹,

Harrison²

1997

New Phytologist

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SUMMARYIon exchange chromatography of water extracts was used to classify the fructans in leaves of 40 temperate dicots and 110 temperate grass species. Of the 150 species studied, only Poa ampla (Merrill) contained a single y5-2,6 linked fructan series. All other species grown at 10/5 °C day/night temperatures (16 h day) contained some /5-l,2 linked oligofructans, even when the major fructan series was /?-2,6 linked. Leaves of P. ampla plants grown at 15/10 °C day/night temperatures contained some /?-l,2 linked fructans and rafiinose in addition to the dominant /?-2,6 series, but did not contain significant amounts of 1-kestose or bifurcose (l&6-kestotetraose). Leaves oi Poa arctica R.Br. and Poa bulbosa L. contained significant amounts of raffinose and various /5-l,2 linked oligomers but no 1-kestose. In vivo synthesis of 6-kestose in leaves of P. ampla grown at 10/5 °C proceeds in the absence of significant amounts of either 1-kestose or bifurcose. Thus P. ampla probably has a specific 6-SST (6-sucrosesucrosefructosyl transferase) and might provide a ready source oi /]-2,6 linked grass fructan.

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Fructan Synthesis in Excised Barley Leaves (Identification of Two Sucrose-Sucrose Fructosyltransferases Induced by Light and Their Separation from Constitutive Invertases)

Cited by 75 publications

References 22 publications

Fructan and fructan‐metabolizing enzymes in the growth zone of barley leaves

Fructan and fructan‐metabolizing enzymes in the growth zone of barley leaves

Isolation of sucrose: sucrose 1‐fructosyltransferase (1‐SST) from barley (Hordeum vulgare)

Fructan oligomers in Poa ampla

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