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Microarray expression analysis of normal and Fe‐hyper‐accumulating Pea (Pisum sativum L.) mutant genotypes and genetic links to Caco‐2 Fe bioavailability
Author(s) -
ArizaNieto Magnolia,
Glahn Raymond P.,
Welch Ross M.
Publication year - 2007
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.21.6.a1114-c
Subject(s) - biochemistry , pisum , methionine , biology , chemistry , mutant , gene , amino acid
Nicotianamine, plays important roles in intra and intercellular Fe movement in all higher plants but the genetic regulation is not completely understood. Three isogenic pea genotypes [Sparkle (wild type), brz and dgl] were studied. Both brz and dgl (Fe toxicity phenotypes) have been reported to over accumulate Nicotianamine. The plants were grown in full strength nutrient solutions. Pea pods at twelve stages of development and fully mature seeds were evaluated. Total RNA was isolated from mature leaves, converted to cDNA and biotin labeled. The pea targets were cross‐species hybridized to nucleic acid probes of the afflymetrix Medicago genechip and/or the Arabidopsis ATH1 array. Preliminary results suggest that the highest concentration of Fe in the pods and seeds was associated with the up‐regulation of methionine‐adenosyl‐transferese and s‐adenosyl‐l‐homocysteinase, both precursors of nicotianamine via the methionine pathway, in dgl compared to Sparkle or brz. Furthermore, in dgl, S‐adenosylmethionine synthase, S‐adenosylmethionine decarboxylase, Pea root Fe transporter protein (PsIT), ferritin and pectin acetylesterase were up‐regulated. Cystathionine‐gamma‐synthase, polygalacturonase2, and the Ps fructose‐1, 6‐biphosphate aldolase were down regulated in dgl. The Fe concentrations in mature dry seeds were: Sparkle, 62 mg/g; brz, 44 mg/g; dgl, 145 mg/g. The bioavailable Fe as determined using Caco‐2 cells was higher in immature pods. These results suggest that up‐regulation of the methionine precursors may lead to increased Fe concentration in seeds via their affects on nicotianamine biosynthesis and subsequent increased mobilization of Fe to developing seeds. Research funded by USDA‐ARS.