Iron and Copper Nutrition-Dependent Changes in Protein Expression in a Tomato Wild Type and the Nicotianamine-Free Mutant chloronerva

Abstract

The nicotianamine-deficient mutant chloronerva resembles phenotypically an Fe-deficient plant despite the high accumulation of Fe in the leaves, whereas it suffers from Cu deficiency in the shoot. Two-dimensional electrophoretic separation of proteins from root tips and leaves of wild-type Lycopersicon esculentum Mill. cv Bonner Beste and the mutant grown with and without Fe showed a number of consistent differences. In root tips of the Fe-deficient wild type and the Fe-sufficient as well as the Fe-deficient mutant, the expression of glyceraldehyde-3-phosphate dehydrogenase, formate dehydrogenase, and ascorbate peroxidase was increased. In leaves of the Fe-sufficient and -deficient mutant, Cu-containing chloroplastic and cytosolic superoxide dismutase (Cu-Zn) and plastocyanin (Cu) were nearly absent. This low plastocyanin content could be restored by supplying Cu via the xylem, but the superoxide dismutase levels could not be increased by this treatment. The differences in the protein patterns between wild type and mutant indicate that the apparent Fe deficiency of mutant plants led to an increase in enzymes involved in anaerobic metabolism as well as enzymes involved in stress defense. The biosynthesis of plastocyanin was diminished in mutant leaves, but it was differentially induced by increased Cu content.

A Program for Iron Economy during Deficiency Targets Specific Fe Proteins

“…In general, proteomic studies have shown changes in protein abundance of oxidative stress response-related proteins such as increases in CuZnSOD, MnSOD, and peroxidase and a decrease in catalase (López-Millán et al, 2013). However, proteomic studies on tomato leaves showed a decrease in CuZnSOD and an increase in cytosolic ascorbate peroxidase with Fe depletion (Herbik et al, 1996). This study shows little effect of Fe deficiency on CuZnSODs or cytosolic ascorbate peroxidase, which might be because the Fe limitation was mild and reversible.…”

“…Untargeted proteomics approaches, as first pioneered with wild-type tomatoes and cloronerva mutans that lack the metal-chelating nicotianamine molecule (Herbik et al, 1996), have the potential to uncover other mechanisms of acclimation to low Fe such as the adjustment of metabolism. A number of studies in various species have investigated the proteome changes after Fe deficiency, the majority focusing on the root proteomic response (for review, see López-Millán et al, 2013).…”

FRD3 Controls Iron Localization in Arabidopsis

“…It is not known where, or via what type of transporter, NA is loaded into the vasculature; this is a possible function for FRD3. However, because the NA-less chln mutant has alterations in copper homeostasis as well as in iron homeostasis (Pich et al, 1994;Herbik et al, 1996) and the frd3 mutant does not have alterations in copper levels (Lahner et al, 2003), it is unlikely that the frd3 mutant has defects in NA metabolism and transport or that the FRD3 protein is involved in NA transport.…”

Towards Understanding Plant Response to Heavy Metal Stress

“…And such histidine-dependent root-to-shoot translocation of Ni was also observed in Brassica juncea (Kerkeb & Kramer, 2003). Nicotianamine (NA), synthesized from three molecules of S-adenosyl-L L-methionine by nicotianamine synthase (NAS), has been primarily linked with Fe and Cu homeostasis (Hell & Stephan, 2003;Herbik et al, 1996;Pich et al, 2001). Through studies on NAS, NA has also been implicated in Zn homeostasis and tolerance (Weber et al, 2004).…”