Iron transport and storage within the seed coat and embryo of developing seeds of pea (Pisum sativumL.)

Abstract

Link to this article: http://journals.cambridge.org/abstract_S0960258500004293How to cite this article: Eduardo Marentes and Michael A. Grusak (1998). Iron transport and storage within the seed coat and embryo of developing seeds of pea ( Pisum sativum L.). AbstractTo understand the cellular processes related to iron transport and sequestration within the developing pea seed (Pisum sativum), total iron and ferntin iron were analysed in seed coat and embryo tissues of the ironhyperaccumulatmg pea mutant, Sparkle [dgl, dgl\, and its wild-type parent, cv Sparkle For plants grown hydroponically with 2 UM Fe, embryo Fe concentrations averaged 65 ug g~1 dry weight in mature wild-type seeds and 163 ug g~1 dry weight in mature dgl seeds, iron concentrations were also higher in dgl seed coats Extracted and electrophoretically separated seed proteins were probed with a polyclonal antibody raised against pea seed ferntin In both genotypes, ferntin was detected in the embryo, but not in the seed coat Ferntin iron accounted for 92% of the total iron in mature wildtype embryos, but only 42% of the total iron in mature dgl embryos Radiotracer studies using 59 Fe were used to characterize the movement of iron within the seed coat Unequal distribution of 59 Fe in opposing sections taken from the two hemispheres of the seed coat demonstrated that iron was symplastically phloem unloaded These results suggest that iron resides transiently within the nonvascular seed coat cells and that all cells at the inner surface of the seed coat may be involved in the release of iron to the embryo apoplast However, the form of iron resident within the seed coat and/or taken up by the embryo is presently unknown Abbreviations EDDHA = N,N'-ethylenebis [2-(2-hydroxyphenyD-glycine], EDTA = Ethylenediammetetraacetic acid, HSF = horse spleen ferntin, PAGE = polyacrylamide gel electrophoresis, PMSF = phenylmethylsulfonyl fluoride, PVP = polyvinylpyrrohdone, WT = wild-type

Structure and differential expression of the four members of the Arabidopsis thaliana ferritin gene family

“…It is also known that under non-stress conditions most of the ferritin protein is found within the seeds, where it accumulates [34]. Furthermore, 92 % of iron found in seed embryos is contained within ferritin molecules [36]. In addition, although the AtFer4 gene has been described on BAC T07M07, which contains a cluster of ABA-regulated genes [37], our results demonstrated that it is not up-regulated in response to treatment with exogenous ABA ( Figure 5).…”

Moving micronutrients from the soil to the seeds: Genes and physiological processes from a biofortification perspective

“…Fe is loaded into the vacuoles by the VIT1 protein during embryo development [168],while upon germination Fe is remobilized from this organelle by the Nramp3 and Nramp4 transporters [169]. In legumes, Fe is stored in ferritin protein in the embryo [170,171] but ferritin is not found in the seed coat [172]. Ferritin is degraded during seed germination [171] thus releasing stored Fe for the growing seedling.…”

Metal Homeostasis in Cyanobacteria and Chloroplasts. Balancing Benefits and Risks to the Photosynthetic Apparatus

“…Ferritins and bacterioferritins oxidize Fe(II) to insoluble Fe(III) prior to its deposition in the core of the protein complex (Curie and Briat, 2003). In cyanobacteria, Fe storage in bacterioferritins can account for up to 50% of the cellular Fe quota (Keren et al, 2004) and in pea (Pisum sativum) seedlings, ferritin Fe accounts for up to 90% of the cellular Fe quota (Marentes and Grusak, 1998). Mn is efficiently leached from the environment by cyanobacteria and is accumulated in the envelope layer of the cells (Keren et al, 2002).…”