Proteomic characterization of iron deficiency responses in Cucumis sativusL. roots

Abstract

BackgroundIron deficiency induces in Strategy I plants physiological, biochemical and molecular modifications capable to increase iron uptake from the rhizosphere. This effort needs a reorganization of metabolic pathways to efficiently sustain activities linked to the acquisition of iron; in fact, carbohydrates and the energetic metabolism has been shown to be involved in these responses. The aim of this work was to find both a confirmation of the already expected change in the enzyme concentrations induced in cucumber root tissue in response to iron deficiency as well as to find new insights on the involvement of other pathways.ResultsThe proteome pattern of soluble cytosolic proteins extracted from roots was obtained by 2-DE. Of about two thousand spots found, only those showing at least a two-fold increase or decrease in the concentration were considered for subsequent identification by mass spectrometry. Fifty-seven proteins showed significant changes, and 44 of them were identified. Twenty-one of them were increased in quantity, whereas 23 were decreased in quantity. Most of the increased proteins belong to glycolysis and nitrogen metabolism in agreement with the biochemical evidence. On the other hand, the proteins being decreased belong to the metabolism of sucrose and complex structural carbohydrates and to structural proteins.ConclusionsThe new available techniques allow to cast new light on the mechanisms involved in the changes occurring in plants under iron deficiency. The data obtained from this proteomic study confirm the metabolic changes occurring in cucumber as a response to Fe deficiency. Two main conclusions may be drawn. The first one is the confirmation of the increase in the glycolytic flux and in the anaerobic metabolism to sustain the energetic effort the Fe-deficient plants must undertake. The second conclusion is, on one hand, the decrease in the amount of enzymes linked to the biosynthesis of complex carbohydrates of the cell wall, and, on the other hand, the increase in enzymes linked to the turnover of proteins.

Acquisition and Homeostasis of Iron in Higher Plants and Their Probable Role in Abiotic Stress Tolerance

“…Down regulated detoxifying proteins in Fe-deprived conditions, viz. CAT2 (CATALASE 2; AT4G35090) proteins and PA2 (PEROXIDASE 2; AT5G06720) proteins, were reported in some plants (Donnini et al, 2010;Rodríguez-Celma et al, 2011). These are enzymes that help in the conversion of H 2 O 2 (hydrogen peroxide) to H 2 O (water) and oxygen.…”

SORTING NEXIN1 Is Required for Modulating the Trafficking and Stability of the Arabidopsis IRON-REGULATED TRANSPORTER1

“…One or more of the iron deficiency-inducible subgroup Ib bHLH proteins (Heim et al, 2003), bHLH038, bHLH039, bHLH100, and bHLH101, needs to be present and probably forms dimers with FIT for the induction to take place (Wang et al, 2007(Wang et al, , 2013Yuan et al, 2008). This was found to be only a small part of the extensive posttranscriptional regulation of the iron uptake system (Brumbarova and Bauer, 2005;Brumbarova et al, 2008;Donnini et al, 2010;Rellán-Alvarez et al, 2010;Lan et al, 2011). AHA1 and AHA2 activity is regulated by phosphorylation of a single amino acid (Fuglsang et al, 2007;Haruta et al, 2010).…”

Natural variation in iron use efficiency and mineral remobilization in cucumber (Cucumis sativus)

“…The primary iron uptake response genes for ferric reductase FRO1, iron transporter IRT1 (Waters et al 2007), and H + -ATPase HA1 (Santi et al 2005) have been identified from cucumber. More recently, the sequencing of the cucumber genome (Huang et al 2009) has opened the possibility for additional genomic scale studies such as proteomic responses of roots to Fe deficiency (Donnini et al 2010;Li and Schmidt 2010). The rapid growth and relatively large size of cucumber organs offers advantages over Arabidopsis thaliana for certain lines of inquiry.…”