Abstract
Plants and seeds are the main dietary sources of zinc, iron, manganese, and copper, but are also the main entry point for toxic elements such as cadmium into the food chain. We report here that an Arabidopsis oligopeptide transporter mutant, opt3-2, over-accumulates cadmium (Cd) in seeds and roots but, unexpectedly, under-accumulates Cd in leaves. The cadmium distribution in opt3-2 differs from iron, zinc, and manganese, suggesting a metal-specific mechanism for metal partitioning within the plant. The opt3-2 mutant constitutively up-regulates the Fe/Zn/Cd transporter IRT1 and FRO2 in roots, indicative of an iron-deficiency response. No genetic mutants that impair the shoot-to-root signaling of iron status in leaves have been identified. Interestingly, shoot-specific expression of OPT3 rescues the Cd sensitivity and complements the aberrant expression of IRT1 in opt3-2 roots, suggesting that OPT3 is required to relay the iron status from leaves to roots. OPT3 expression was found in the vasculature with preferential expression in the phloem at the plasma membrane. Using radioisotope experiments, we found that mobilization of Fe from leaves is severely affected in opt3-2, suggesting that Fe mobilization out of leaves is required for proper trace-metal homeostasis. When expressed in yeast, OPT3 does not localize to the plasma membrane, precluding the identification of the OPT3 substrate. Our in planta results show that OPT3 is important for leaf phloem-loading of iron and plays a key role regulating Fe, Zn, and Cd distribution within the plant. Furthermore, ferric chelate reductase activity analyses provide evidence that iron is not the sole signal transferred from leaves to roots in leaf iron status signaling.
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Claims 12
Claim · model-written summary
The opt3-2 mutant overaccumulates cadmium in seeds and roots.
- Taxon
- Arabidopsis
Arabidopsise0 - Material
- opt3-2e0
- Outcome
- cadmium (Cd) in seeds and rootse0
- Direction
- over-accumulatese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“an Arabidopsis oligopeptide transporter mutant, opt3-2, over-accumulates cadmium (Cd) in seeds and roots”
Claim · model-written summary
The opt3-2 mutant underaccumulates cadmium in leaves.
- Taxon
- ArabidopsisArabidopsise0
- Material
- opt3-2e0
- Outcome
- Cd in leavese0
- Direction
- under-accumulatese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“an Arabidopsis oligopeptide transporter mutant, opt3-2, over-accumulates cadmium (Cd) in seeds and roots but, unexpectedly, under-accumulates Cd in leaves”
Claim · model-written summary
Cadmium distribution in opt3-2 differs from that of iron, zinc and manganese.
- Taxon
- ArabidopsisArabidopsise1
- Material
- opt3-2e0
- Outcome
- cadmium distributione0
- Comparator
- iron, zinc, and manganesee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The cadmium distribution in opt3-2 differs from iron, zinc, and manganese”
e1“an Arabidopsis oligopeptide transporter mutant”
Claim · model-written summary
The opt3-2 mutant constitutively upregulates IRT1 in roots.
- Taxon
- ArabidopsisArabidopsise1
- Material
- opt3-2e0
- Gene
- IRT1e0
- Outcome
- Fe/Zn/Cd transporter IRT1e0
- Direction
- up-regulatese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The opt3-2 mutant constitutively up-regulates the Fe/Zn/Cd transporter IRT1 and FRO2 in roots”
e1“an Arabidopsis oligopeptide transporter mutant”
Claim · model-written summary
The opt3-2 mutant constitutively upregulates FRO2 in roots.
- Taxon
- ArabidopsisArabidopsise1
- Material
- opt3-2e0
- Gene
- FRO2e0
- Outcome
- FRO2 in rootse0
- Direction
- up-regulatese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The opt3-2 mutant constitutively up-regulates the Fe/Zn/Cd transporter IRT1 and FRO2 in roots”
e1“an Arabidopsis oligopeptide transporter mutant”
Claim · model-written summary
Shoot-specific OPT3 expression rescued cadmium sensitivity in opt3-2.
- Taxon
- ArabidopsisArabidopsise1
- Material
- opt3-2e0
- Treatment
- shoot-specific expression of OPT3e0
- Gene
- OPT3e0
- Outcome
- Cd sensitivitye0
- Direction
- rescuese0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“shoot-specific expression of OPT3 rescues the Cd sensitivity and complements the aberrant expression of IRT1 in opt3-2 roots”
e1“an Arabidopsis oligopeptide transporter mutant”
Claim · model-written summary
Shoot-specific OPT3 expression complemented aberrant IRT1 expression in opt3-2 roots.
- Taxon
- ArabidopsisArabidopsise1
- Material
- opt3-2e0
- Treatment
- shoot-specific expression of OPT3e0
- Gene
- IRT1e0
- Outcome
- aberrant expression of IRT1 in opt3-2 rootse0
- Direction
- complementse0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“shoot-specific expression of OPT3 rescues the Cd sensitivity and complements the aberrant expression of IRT1 in opt3-2 roots”
e1“an Arabidopsis oligopeptide transporter mutant”
Claim · model-written summary
OPT3 expression occurred in vasculature, preferentially in phloem at the plasma membrane.
- Taxon
- ArabidopsisArabidopsise1
- Organ / stage
- phloeme0
- Gene
- OPT3e0
- Outcome
- OPT3 expression was found in the vasculature with preferential expression in the phloem at the plasma membranee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“OPT3 expression was found in the vasculature with preferential expression in the phloem at the plasma membrane”
e1“an Arabidopsis oligopeptide transporter mutant”
Claim · model-written summary
Iron mobilization from leaves was severely affected in opt3-2.
- Taxon
- ArabidopsisArabidopsise1
- Material
- opt3-2e0
- Outcome
- mobilization of Fe from leavese0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“mobilization of Fe from leaves is severely affected in opt3-2”
e1“an Arabidopsis oligopeptide transporter mutant”
Claim · model-written summary
OPT3 expressed in yeast did not localize to the plasma membrane.
- Taxon
- ArabidopsisArabidopsise1
- Gene
- OPT3e0
- Outcome
- does not localize to the plasma membranee0
- Setting
- yeaste0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“When expressed in yeast, OPT3 does not localize to the plasma membrane”
e1“an Arabidopsis oligopeptide transporter mutant”
Claim · model-written summary
OPT3 is important for leaf phloem loading of iron and regulation of Fe, Zn and Cd distribution.
- Taxon
- ArabidopsisArabidopsise1
- Gene
- OPT3e0
- Outcome
- leaf phloem-loading of iron and plays a key role regulating Fe, Zn, and Cd distribution within the plante0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“OPT3 is important for leaf phloem-loading of iron and plays a key role regulating Fe, Zn, and Cd distribution within the plant”
e1“an Arabidopsis oligopeptide transporter mutant”
Claim · model-written summary
Ferric chelate reductase activity indicated that iron is not the sole leaf-to-root signal.
- Taxon
- ArabidopsisArabidopsise1
- Outcome
- iron is not the sole signal transferred from leaves to rootse0
- Qualifier
- leaf iron status signalinge0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“ferric chelate reductase activity analyses provide evidence that iron is not the sole signal transferred from leaves to roots in leaf iron status signaling”
e1“an Arabidopsis oligopeptide transporter mutant”
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See all 46 papers →Claims are grouped by organism, treatment and what was measured or targeted. A paper counts as positive when any of its claims in the group is positive.