Inositol phosphates plants

Lehrfeld, J. HPLC separation and quantitation of phytic acid and some inositol phosphates in foods. J Agr Food Chem 1994 42(12) 2726-2731. Obata, H., K. Imai, N. Inoue, and M. Umebayashi. A highly sensitive quantitative determination of glutathione in plant roots by high performance gel filtration chromatography and fluoro-metic detection after pre-column derivatization with N-(7-dimethyl-amino-4-methyl coumarinyl)-malei-mide. Phytochem Anal 1994 5(5) 239-242. 

Fatty acids are known to play an important role in signal transduction pathways via the inositol phosphate mechanism in both plants and animals. In animals, several polyunsaturated fatty acids like linolenic acid are precursors for hormones. Interruption of fatty acid... 

The variability of the P content of fulvic acids appears to be a function of both the hydrologic conditions and the nutrient status of the aquatic system in which the fulvic acids were formed. McKnight et al. (1985) hypothesized that the P in Thoreau s Bog fulvic acids was in the form of organic phosphate esters or inositol phosphates, which are major phosphorus products from the breakdown of plant material. The solubility of these P-containing moieties would be greater in bogwater than in most surface... 

Few data are available on the PolyP function in higher plants. PolyPs were first observed in maize roots (Vagabov and Kulaev, 1964), while Niemeyer studied PolyPs and their interactions with the inositol phosphate pools in plants (Niemeyer, 1975, 1976, 1999 Niemeyer and Selle, 1989). Some data on the dynamics of PolyPs during the development of cotton plants were obtained (Valikhanov et al., 1980). It is probable that some plants can use extracellular PolyP as a phosphorus source (Igamnazarov and Valikhanov, 1980). 

R. Niemeyer and H. Selle (1989). Inorganic condensed phosphates and inositol phosphates in plant nuclei. Biol. Chem. Hoppe Seyler, 386, 1088. 

Murthy, P.P.N., 1996, Metabolism of inositol phosphates in plants. In Biswas, B.B. and Biswas, S. (eds.), Inositol Phosphates, Phosphoinositides, and Signal Transduction, Subcellular Biochemistry Series, Vol. 26, Plenum Press, New York, pp. 227-255. 

Ockenden, I., Dorsch, J.A., Reid, M.M., Lin, L., Grant, L.K., Raboy, V, and Lott, J.N.A., 2004, Characterization of the storage of phosphorus, inositol phosphate and cations in grain tissues of four barley (Hordeum vulgare L.) low phytic acid genotypes. Plant Sci. 167 1131-1142. 

Shi, J., Wang, H., Wu, Y., Hazebroek, J., Meeley, R.B., and Ertl, D.S., 2003, The maize low phytic acid mutant lpa2 is caused by mutation in an inositol phosphate kinase gene. Plant Physiol. 131 In Press. 

Furthermore, phosphoinositide/inositol phosphate turnover plays an important role in the production of secondary messengers during abiotic stress in plants. Within a few seconds, hyperosmotic shock induced a rapid and transient increase of Ins( 1,4,5)P3 in Arabidopsis cultured cells. This fact strongly suggests the PI turnover system functions near an osmosensor however, the molecule that functions as the osmosensor has not been identified, except in yeast and bacteria. In the near future, we hope to determine which molecule can activate the PI turnover system in response to hyperosmotic stress in plants. 

InsPg, also known as phytic acid, was the first inositol phosphate discovered (Posternak, 1919). Initially, InsPg was thought to exist only in plants (mostly legumes) and in the erythrocytes of a few animals. However, it is now known to be ubiquitous in mammalian (and probably all eukaryotic) cells (Heslop et al., 1985), and may actually be the most abundant inositol phosphate. 

Smart, C.C., and Fleming, A.J., 1993, A plant gene with homology to D-myo-inositol-phosphate synthase is rapidly and specially upregulated during an abscsic acid induced response in Spirodelapolyrrihiza. Plant J. 4 279-293. 

Plant foods contain relatively large amounts of inositol phosphates, including the hexaphosphate, phytic acid. Phytate chelates minerals, such as calcium, zinc, and magnesium, forming insoluble complexes that are not absorbed. However, both intestinal phosphatases and endogenous phosphatases (phytase) in many foods dephosphorylate a significant proportion of dietary phytate. The inositol released can be absorbed and utilized for phosphatidylinositol synthesis. 

In plants, inositol is biosynthesized from glucose 1-phosphate via inosose 1-phosphate, which is reduced into ID-inositol 3-phosphate (INOl pathway). After dephosphorylation by inositol phosphate monophosphatase, myo-inositol is fed into biosynthesis of inositol phospholipids via a Kennedy-like sequence. In mammalian organisms, inositol is acquired from the diet and is also biosynthesized via INOl. The latter pathway, rather than the inositol phosphate phosphatase, seems to be a more promising target of antipsychotic drugs (17, 18) (see Fig. 2). 

Suzumura and Kamatani (1995) pursued a study of the fate of inositol phosphates in sediments, another specific class of compounds that can be isolated and quantified, with the quite different aim of evaluating whether these terrestrial plant-derived Porg compounds might be refractory in the marine environment. Their results suggest that these compounds are minor constituents of total Porg in marine sediments, and that they are vulnerable to microbial breakdown during early... 

Hong, J. K. and Yamane, I. (1981). Distribution of inositol phosphate in the molecular size fractions of humic and fulvic acid fractions. Soil Sci. Plant Nutr. 27, 295-303. 

Hong, J.K. and Yamane, I. (1980) Examination of the conventional method and a proposal for a new method of determining inositol phosphate in the humic acid fraction. Soil Science and Plant Nutrition (Tokyo) 26, 497-505. 

The inositol hexa- and pentakisphos-phates are prevalent in soils compared to lower-order esters, probably because stability in the soil is linked to the number of phosphate groups. The most widespread stereoisomer is myo-inositol (Dalai, 1977). Inositol phosphates are more resistant to mineralization than the other fractions of the soil organic phosphorus and, therefore, are probably poorly available to plants (Williams and Anderson, 1968). They are present in soils in highly complex forms associated with clay minerals, fulvic and humic acids (Anderson and Arlidge, 1962), proteins and some metallic ions (Rojo et al., 1990). The various forms of inositol phosphates are often imprecisely referred to as phytic acid, which is reserved exclusively for the free acid form of myo-inositol hexakisphosphate. Salt forms of myo-inositol hexakisphosphate, also known as phytates, are very stable and consequently accumu-... 

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