A transfer of carbon atoms from fatty acids to sugars and amino acids in yellow lupine (Lupinus luteus L.) seedlings

Borek, Sławomir; Ratajczak, W.; Ratajczak, Lech

doi:10.1078/0176-1617-00763

Cited by 20 publications

(37 citation statements)

References 21 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…A third and more speculative possibility is supported by evidence from radiolabeling experiments in germinating lupines. A direct interaction between fatty acid metabolism and amino acids was shown in yellow lupine (Lupinus luteus) seedlings (Borek et al, 2003). It was demonstrated that, in the seedling axis, C atoms from acetate were incorporated mainly into amino acids upon germination.…”

Section: Interaction Between Storage Reserve Accumulation and Gaba Shmentioning

confidence: 94%

Targeted Enhancement of Glutamate-to-γ-Aminobutyrate Conversion in Arabidopsis Seeds Affects Carbon-Nitrogen Balance and Storage Reserves in a Development-Dependent Manner

et al. 2011

View full text Add to dashboard Cite

In seeds, glutamate decarboxylase (GAD) operates at the metabolic nexus between carbon and nitrogen metabolism by catalyzing the unidirectional decarboxylation of glutamate to form g-aminobutyric acid (GABA). To elucidate the regulatory role of GAD in seed development, we generated Arabidopsis (Arabidopsis thaliana) transgenic plants expressing a truncated GAD from Petunia hybrida missing the carboxyl-terminal regulatory Ca 2+ -calmodulin-binding domain under the transcriptional regulation of the seed maturation-specific phaseolin promoter. Dry seeds of the transgenic plants accumulated considerable amounts of GABA, and during desiccation the content of several amino acids increased, although not glutamate or proline. Dry transgenic seeds had higher protein content than wild-type seeds but lower amounts of the intermediates of glycolysis, glycerol and malate. The total fatty acid content of the transgenic seeds was 50% lower than in the wild type, while acyl-coenzyme A accumulated in the transgenic seeds. Labeling experiments revealed altered levels of respiration in the transgenic seeds, and fractionation studies indicated reduced incorporation of label in the sugar and lipid fractions extracted from transgenic seeds. Comparative transcript profiling of the dry seeds supported the metabolic data. Cellular processes up-regulated at the transcript level included the tricarboxylic acid cycle, fatty acid elongation, the shikimate pathway, tryptophan metabolism, nitrogen-carbon remobilization, and programmed cell death. Genes involved in the regulation of germination were similarly up-regulated. Taken together, these results indicate that the GAD-mediated conversion of glutamate to GABA during seed development plays an important role in balancing carbon and nitrogen metabolism and in storage reserve accumulation.Efficient assimilation of carbon (C) and nitrogen (N) is essential for optimal plant growth, productivity, and yield (Stitt, 1999), particularly in seeds in which the content of essential amino acids is low. Hence, a comprehensive understanding of seed development and metabolism is central to the enhancement of crop yield and quality. Seed development can be divided into three phases: cell division, maturation (accumulation of food reserves), and desiccation (Weber et al., 2005). The shift from one phase to the other is affected by sugars (Suc, hexoses, trehalose) and abscisic acid. In the early stages of seed development, maternal regulation is maintained via assimilate unloading and supply of nutrients, thereby sustaining cell division. During maturation, seed metabolism changes and storage reserves accumulate in expanding cells. At this time, photosynthetic activity is initiated in the seed, which is believed to improve oxygen supply and the energy state in the seed, thus counteracting increasingly hypoxic conditions (Borisjuk and Rolletschek, 2009). The maturation stage is followed by a phase termed "maturation drying," in which the metabolism of Arabidopsis (Arabidopsis thaliana) seeds shifts from a gen...

show abstract

Section: Interaction Between Storage Reserve Accumulation and Gaba Shmentioning

confidence: 94%

Targeted Enhancement of Glutamate-to-γ-Aminobutyrate Conversion in Arabidopsis Seeds Affects Carbon-Nitrogen Balance and Storage Reserves in a Development-Dependent Manner

et al. 2011

View full text Add to dashboard Cite

show abstract

“…During germination storage lipid is used as respiratory substrate, but part of lipid-derived carbon skeletons is used for amino acids biosynthesis. Asparagine, glutamine and glutamate are the main amino acids synthesized from lipid-derived carbon skeletons (Borek et al 2003; Borek and Ratajczak 2010). Moreover, when synthesis of asparagine is disrupted (by L-methionine sulfoximine-an inhibitor of glutamine synthetase), the increase in lipid utilization is observed.…”

Section: Introductionmentioning

confidence: 99%

Regulation by sucrose of storage compounds breakdown in germinating seeds of yellow lupine (Lupinus luteus L.), white lupine (Lupinus albus L.) and Andean lupine (Lupinus mutabilis Sweet): I. Mobilization of storage protein

Borek

Kubala

2011

Acta Physiol Plant

Self Cite

View full text Add to dashboard Cite

Research of the regulatory function of sucrose in storage protein breakdown was conducted on isolated embryo axes, excised cotyledons and whole seedlings of three lupine species grown in vitro on medium with 60 mM sucrose or without the sugar. Sucrose stimulated growth of yellow, white and Andean lupine isolated embryo axes and cotyledons but growth of seedlings was inhibited. Dry matter content was higher in sucrose-fed isolated organs and in seedling organs. Ultrastructure research revealed that lack of sucrose in the medium caused enhancement in storage protein breakdown. Protein deposits in cotyledons were smaller as well as soluble portion content in all studied organs was lower when there was no sucrose in the medium. In the same conditions, the activity of glutamate dehydrogenase was significantly higher. Increase in vacuolization of cells of white lupine root meristematic zone cells was observed and induction of autophagy in young carbohydrate-starved embryo axes is discussed.

show abstract

“…This enzyme takes part in gluconeogenesis and its activity in germinating yellow lupine seeds has also been detected (Ratajczak et al 1998). However, our earlier results on yellow lupine seed germination with exogenously applied 1-and 2-14 C acetate have shown lower flow of radioactivity into sugars than into amino acids (Borek et al 2003;Borek and Ratajczak 2010), which suggests restricted carbon flow through PEPCK. Therefore, the release of 14 CO 2 with the carbon atoms from C-2 position may be attributed only to reactions of the TCA cycle.…”

Section: Discussionmentioning

confidence: 97%

“…Radiolabeled experiments were conducted according to modified method described previously (Borek et al 2003). Embryo axes (8 samples) and cotyledons (8 samples of yellow and Andean lupine and 6 samples of white lupine) grown in vitro were incubated in 8 ml of Heller medium (?S and -S) containing 30 mM NaF (inhibitor of glycolysis/gluconeogenesis), mixture of 0.035 mM KCN, 0.035 mM NaN 3 , 0.15 mM SHAM (inhibitors of mitochondrial respiration) or 1 mM MSO (inhibitor of glutamine synthetase).…”

Section: Experiments With Radiolabeled Acetatementioning

confidence: 99%

“…The high incorporation of carbon atoms coming from storage lipid has been noticed especially in amino acids belonging to the primary amino acid biosynthesis pathway, i.e. asparagine as well as glutamine, glutamate and aspartate (Borek et al 2003;Borek and Ratajczak 2010). It is postulated that the intermediates of glyoxylate cycle are the source of carbon skeletons for amino acids synthesis (Borek and Ratajczak 2010).…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Comparative study of storage compound breakdown in germinating seeds of three lupine species

2011

Self Cite

View full text Add to dashboard Cite

Storage lipid and protein breakdown in germinating seeds of yellow (Lupinus luteus L.), white (L. albus L.), and Andean lupine (L. mutabilis Sweet) and regulatory function of sucrose were investigated. Less oil bodies were detected in organs of yellow lupine seeds, whereas the highest content of oil bodies was noticed in the Andean lupine seeds. Mature, air-dried yellow, white and Andean lupine seeds do not contain starch. Starch grains appear the earliest in white lupine seeds during imbibition. Sucrose deficiency in tissues enhances breakdown of storage lipid, protein and temporary starch in cotyledons. In sucrose starved embryo axes of all investigated lupine species, an increased level of vacuolization was noted. Interconnections between catabolism of storage protein and storage lipid in germinating lupine seeds were identified by applying 14 C-acetate. To assess the importance of key processes in storage lipid breakdown NaF (inhibitor of glycolysis and gluconeogenesis), KCN, NaN 3 and SHAM (inhibitors of mitochondrial electron transport chain) and MSO (inhibitor of glutamine synthetase) were used. Radioactivity coming from 14 C-acetate was released as 14 CO 2 but mostly was incorporated into ethanol-soluble fraction of embryo axes and cotyledons. Respiratory inhibitors caused a significant decrease in 14 CO 2 and ethanol fractions in all three lupine species studied. MSO stimulated release of 14 CO 2 and radioactivity of ethanol fractions in yellow lupine organs fed with sucrose, but in Andean lupine MSO enhanced the production of 14 CO 2 and radioactivity of ethanol fractions both in organs fed and not fed with sucrose. Different strategies of storage compound breakdown are proposed, depending on relative proportion in storage protein and lipid content in lupine seeds.

show abstract

A transfer of carbon atoms from fatty acids to sugars and amino acids in yellow lupine (Lupinus luteus L.) seedlings

Cited by 20 publications

References 21 publications

Targeted Enhancement of Glutamate-to-γ-Aminobutyrate Conversion in Arabidopsis Seeds Affects Carbon-Nitrogen Balance and Storage Reserves in a Development-Dependent Manner

Targeted Enhancement of Glutamate-to-γ-Aminobutyrate Conversion in Arabidopsis Seeds Affects Carbon-Nitrogen Balance and Storage Reserves in a Development-Dependent Manner

Regulation by sucrose of storage compounds breakdown in germinating seeds of yellow lupine (Lupinus luteus L.), white lupine (Lupinus albus L.) and Andean lupine (Lupinus mutabilis Sweet): I. Mobilization of storage protein

Comparative study of storage compound breakdown in germinating seeds of three lupine species

Contact Info

Product

Resources

About