White lupin

AiTKEN s M, ATTUCCi s, IBRAHIM R K. and GULIK p J (1995) A cDNA encoding geranylgeranyl pyrophosphate synthase from white lupin . Plant Physiol, 108, 837-8. 

Root products, as defined by Uren and Reisenauer (17), represent a wide range of compounds. Only secretions are deemed to have a direct and immediate functional role in the rhizosphere. Carbon dioxide, although labeled an excretion, may play a role in rhizosphere processes such as hyphal elongation of vesicular-arbuscular mycorrhiza (39). Also, root-derived CO2 may have an effect on nonphotosynthetic fixation of CO2 by roots subject to P deficiency and thus contribute to exudation of large amounts of citrate and malate, as observed in white lupins (40). The amounts utilized are very small and, in any case, are extremely difficult to distinguish from endogenous CO2 derived from soil and rhizosphere respiration. 

In soil, the chances that any enzyme will retain its activity are very slim indeed, because inactivation can occur by denaturation, microbial degradation, and sorption (61,62), although it is possible that sorption may protect an enzyme from microbial degradation or chemical hydrolysis and retain its activity. The nature of most enzymes, particularly size and charge characteristics, is such that they would have very low mobility in soils, so that if a secreted enzyme is to have any effect, it must operate close to the point of secretion and its substrate must be able to diffuse to the enzyme. Secretory acid phosphatase was found to be produced in response to P-deficiency stress by epidermal cells of the main tap roots of white lupin and in the cell walls and intercellular spaces of lateral roots (63). Such apoplastic phosphatase is safe from soil but can be effective only when presented with soluble organophosphates, which are often present in the soil. solution (64). However, because the phosphatase activity in the rhizo-sphere originates from a number of sources (65), mostly microbial, and is much higher in the rhizosphere than in bulk soil (66), it seems curious that plants would have a need to secrete phosphatase at all. 

B. Dinkelaker, Rdmheld, V., and H. Mar.schner, Citric acid excretion and precipitation of calcium citrate in the rhizosphere of white lupin (Lupinus aihus L.). Plant. Cell Environ. /2 285 (1989). 

Figure 2 Microbial degradation of citrate in aerated root washings of P-deficient white lupin 5.5 h after removal of the root systems from the trap solution.

Figure 5 Model of phosphorus (P) deficiency-induced physiological changes associated with the release of P-mobilizing root exudates in cluster roots of white lupin. Solid lines indicate stimulation and dotted lines inhibition of biochemical reaction sequences or mclaholic pathways in response to P deliciency. For a detailed description see Sec. 4.1. Abbreviations SS = sucrose synthase FK = fructokinase PGM = phosphoglueomutase PEP = phosphoenol pyruvate PE PC = PEP-carboxylase MDH = malate dehydrogenase ME = malic enzyme CS = citrate synthase PDC = pyruvate decarboxylase ALDH — alcohol dehydrogenase E-4-P = erythrosc-4-phosphate DAMP = dihydraxyaceConephos-phate APase = acid phosphatase.

Especially in dicotyledonous plant species such as tomato, chickpea, and white lupin (82,111), with a high cation/anion uptake ratio, PEPC-mediated biosynthesis of carboxylates may also be linked to excessive net uptake of cations due to inhibition of uptake and assimilation of nitrate under P-deficient conditions (Fig. 5) (17,111,115). Excess uptake of cations is balanced by enhanced net re-lea,se of protons (82,111,116), provided by increased bio.synthesis of organic acids via PEPC as a constituent of the intracellular pH-stat mechanism (117). In these plants, P deficiency-mediated proton extrusion leads to rhizosphere acidification, which can contribute to the. solubilization of acid soluble Ca phosphates in calcareous soils (Fig. 5) (34,118,119). In some species (e.g., chickpea, white lupin, oil-seed rape, buckwheat), the enhanced net release of protons is associated with increased exudation of carboxylates, whereas in tomato, carboxylate exudation was negligible despite intense proton extrusion (82,120). 

Increased root exudation of amino acids in response to Cd toxicity has been reported for lettuce and white lupin grown in a hydroponic culture system under... 

G. Neumann, A. Massonneau, E. Martinoia, and V. Romheld, Physiological adaptations to phosphorus deficiency during proteoid root development in white lupin. Planta 208 313 (1999). 

G. Keerthisinghe, P. J. Hooking, P. R. Ryan, and E. Delhaize, Effect of phosphorus supply on the formation and function of proteoid roots of white lupin (Lupinus albiis L.). Plant Cell Environm. 21 467 (1998). 

M. Watt and J. Evans, Linking development and determinacy with organic acid efflux from proteoid roots of white lupin grown with low phosphorus and ambient or elevated atmospheric COi concentration. Plant Pltywlol. 120 705 (1999). 

M. Kamh, W. J. Horst, F. Amer, and H. Mostafa, Exudation of organic anions by white lupin Lupinus albus L.) and their role in phosphate mobilization from... 

G. Costa, J. C. Michaut, and A. Guckert, Amino acids exuded from axenic roots of lettuce and white lupin seedlings exposed to different cadmium concentrations. J. Plant Nutr. 20 883 (1997). 

H. Gagnon, 3. Seguin, E. Bleichert, S. Tahara, and R. K. Ibrahim, Biosynthesis of white lupin isoflavonoids from (U- C]L-phenylalanine and their release into the culture medium. Plant Physiol. 100 16 (1992). 

G. A. Gilbert, C. P. Vance, and D. L. Allan. Regulation of white lupin root metabolism by phosphorus availability. Phosphorus in Plant Biology Regulatory Roles in Molecular. Cellular, Organismlc, and Ecosystem Processes (J. P. Lynch and J. Deikman. eds,), American Society of Plant Physiologists, 1998, p. 157. 

G. Neumann, E. George, and V. Romheld, White lupin—a model plant to study mechanisms involved in root-induced mobilization of sparingly available P-sources, International Workshop on Role of Environmental and Biological Factors of To.xic and Essential Elements by Plants. Research Institute of Pomology and Floriculture, Skierniewice, Poland, 1998, p. 27. 

P. Wojtaszek, M. Stobiecki, and K. Gulewicz, Role of nitrogen and plant growth regulators in the exudation and accumulation of isoflavonoids by roots of intact white lupin (Lupinus aihus L.) plants. J. Plant Phy.siol. 742 689 (1993). 

Other sand-based systems using COi pulse-chase procedures have been used to produce carbon budgets for Festuca ovina and Plantago lanceolata seedlings (30) and white lupin (Lupimis albiis) (31). Significantly, CO2 pulse labeling of proteoid roots of white lupin under phosphate-deficient conditions showed that high levels of dark fixation of COi by the roots took place and that 66% of this root-fixed carbon was exuded from the roots (31). Clearly, dark fixation of CO2 by roots and subsequent rhizodeposition is an area that deserves further study in the future. 

Next to the amount of P, the chemical form of this nutrient (Lambers et al. 2002 Shu et al. 2005 Shane et al. 2008) and the availability of other nutrients, especially nitrogen, potassium, and iron (Shane and Lambers 2005) affects the formation of cluster roots. It seems to be regulated by several plant hormones. Thus, application of auxin led to the production of cluster roots in white lupin at P concentrations that normally suppress cluster roots (Gilbert etal. 2000 Neumann et al. 2000). Cytokinines might also play a role, as kinetin applied to the growth medium of P-deficient white lupin inhibited the formation of cluster roots (Neumann et al. 2000). 

Neumann G, Massonneau A, Langlade N, Dinkelaker B, Hengeler C, Romheld V, Martinoia E (2000) Physiological aspects of cluster root function and development in phosphorus-deficient white lupin (Lupinus albus L.). Ann Bot 85 909-919. doi http //aob.oxfordjournals.org/cgi/ content/abstract/85/6/909... 

The simple ohservahon that white seeds are sweeter that black seeds was used in the construction of a practical method of judging lupine seeds qualitatively. This method cannot he used with confidence, because, especially in white lupine, even very white seeds can have a high alkaloid content. On the other hand, plants from the same species are sweet . In some species, for example in the case of L. angustifolius or l. luteus, the tendency of white seeds to be sweet is more likely but not absolutely certain. 

Baer von, D. and P6rez, I. 1990. Quality standard proposition for commercial grain of white lupin (Lupinus albus). In 6th International Lupin Conference. Proceedings, pp. 158-167. Temuco-Pucon ILA. 

The formation of phytoalexins such as glyceollins and phaseollins requires C-prenylation by a range of pterocarpan prenyltransferase (PTP) activities, with dimethylallyl pyrophosphate (DMAPP) as the prenyl donor. For glyceollins and phaseollins, prenylation occurs at position C-2 or C-4 of glycinol or C-10 of 3,9-dihydroxypterocarpan. ° ° However, there are differing activities in other species. For example, in Lupinus albus (white lupin) a prenyltransferase acting at the C-6, -8, and -3 positions of isoflavones has been identified.PTPs have also been characterized in detail for the formation of prenylated flavanones in Sophora flavescens (see, e.g., Ref. 207). However, no cDNA clones for flavonoid-related prenyltransferases have been published to date. 

Laflamme, P. et al.. Enzymatic prenylation of isoflavones in white lupin. Phytochemistry, 34, 147, 1993. 

Mitsuyoshi, S. et al., A new class of biflavonoids 2 -hydroxygenistein dimers from the roots of white lupin, Z. Naturforsck, 55, 165, 2000. 

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