Journal Article

Localization of <i>myo</i>-inositol-1-phosphate synthase to the endosperm in developing seeds of <i>Arabidopsis</i>

Naoto Mitsuhashi, Maki Kondo, Satoru Nakaune, Miwa Ohnishi, Makoto Hayashi, Ikuko Hara-Nishimura, Alan Richardson, Hidehiro Fukaki, Mikio Nishimura and Tetsuro Mimura

in Journal of Experimental Botany

Published on behalf of Society for Experimental Biology

Volume 59, issue 11, pages 3069-3076
Published in print August 2008 | ISSN: 0022-0957
Published online July 2008 | e-ISSN: 1460-2431 | DOI: http://dx.doi.org/10.1093/jxb/ern161

Show Summary Details

Preview

Expression and localization of myo-inositol-1-phosphate synthase (MIPS) in developing seeds of Arabidopsis thaliana was investigated. MIPS is an essential enzyme for production of inositol and inositol phosphates via its circularization of glucose-6-phosphate as the initial step. myo-inositol-6-phosphate (InsP6 or phytic acid) is the predominant form of phosphorus found in seeds and accumulates as a consequence of MIPS action. Three MIPS genes have been identified in Arabidopsis, all of which were expressed not only in siliques but in both leaves and roots. Immunoelectron microscopy using a MIPS antibody showed that MIPS localizes to the cytosol primarily in the endosperm during seed development and not in the embryo. This is consistent with results obtained using fluorescent microscopy and western blot analysis that showed a similar pattern of localization. However, InsP6, which is the final product of inositol phosphate metabolism, was present mainly in the embryo. This suggests that a complex interaction between the endosperm and embryo occurs during the synthesis and subsequent accumulation of InsP6 in developing seeds of Arabidopsis.

Keywords: Inositol; inositol phosphates; inositol-6-phosphates; myo-inositol-1-phosphate synthase; phosphate; phytate; vacuole

Journal Article.  4772 words.  Illustrated.

Subjects: Plant Sciences and Forestry

Users without a subscription are not able to see the full content. Please, subscribe or login to access all content.