Abstract
In search for the cellular and molecular basis for differences in aluminum (Al) resistance between maize (Zea mays) cultivars we applied the patch-clamp technique to protoplasts isolated from the apical root cortex of two maize cultivars differing in Al resistance. Measurements were performed on protoplasts from two apical root zones: The 1- to 2-mm zone (DTZ), described as most Al-sensitive, and the main elongation zone (3-5 mm), the site of Al-induced inhibition of cell elongation. Al stimulated citrate and malate efflux from intact root apices, revealing cultivar differences. In the elongation zone, anion channels were not observed in the absence and presence of Al. Preincubation of intact roots with 90 microM Al for 1 h induced a citrate- and malate-permeable, large conductance anion channel in 80% of the DTZ protoplasts from the resistant cultivar, but only 30% from the sensitive cultivar. When Al was applied to the protoplasts in the whole-cell configuration, anion currents were elicited within 10 min in the resistant cultivar only. La3+ was not able to replace or counteract with Al3+ in the activation of this channel. In the presence of the anion-channel blockers, niflumic acid and 4, 4'-dinitrostilbene-2, 2'disulfonic acid, anion currents as well as exudation rates were strongly inhibited. Application of cycloheximide did not affect the Al response, suggesting that the channel is activated through post-translational modifications. We propose that the Al-activated large anion channel described here contributes to enhanced genotypical Al resistance by facilitating the exudation of organic acid anions from the DTZ of the maize root apex.
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Claims 10
Claim · model-written summary
Al stimulates citrate and malate efflux from intact maize root apices, with cultivar differences.
Zea maysNot reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“protoplasts isolated from the apical root cortex of two maize cultivars differing in Al resistance”
e2“Al stimulated citrate and malate efflux from intact root apices, revealing cultivar differences”
Claim · model-written summary
In the elongation zone, anion channels were not observed with or without Al.
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“protoplasts isolated from the apical root cortex of two maize cultivars differing in Al resistance”
e3“In the elongation zone, anion channels were not observed in the absence and presence of Al”
Claim · model-written summary
Preincubation with 90 microM Al for 1 h induces a citrate- and malate-permeable anion channel in 80% of DTZ protoplasts from the resistant cultivar.
- Material
- resistant cultivare4
- Organ / stage
- DTZ protoplastse4
- Treatment
- Preincubation of intact roots with 90 microM Al for 1 he4
- Outcome
- anion channele4
- Direction
- inducede4
- Value
- 80%e4
- Qualifier
- citrate- and malate-permeable, large conductancee4
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“protoplasts isolated from the apical root cortex of two maize cultivars differing in Al resistance”
e4“Preincubation of intact roots with 90 microM Al for 1 h induced a citrate- and malate-permeable, large conductance anion channel in 80% of the DTZ protoplasts from the resistant cultivar”
Claim · model-written summary
The Al-induced anion channel occurs in a lower share (30%) of DTZ protoplasts from the sensitive cultivar than from the resistant cultivar.
- Material
- sensitive cultivare5
- Treatment
- Preincubation of intact roots with 90 microM Al for 1 he4
- Outcome
- anion channele4
- Direction
- lowerinferrede4
- Value
- 30%e5
- Comparator
- resistant cultivare4
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“protoplasts isolated from the apical root cortex of two maize cultivars differing in Al resistance”
e4“Preincubation of intact roots with 90 microM Al for 1 h induced a citrate- and malate-permeable, large conductance anion channel in 80% of the DTZ protoplasts from the resistant cultivar”
e5“but only 30% from the sensitive cultivar”
Claim · model-written summary
La3+ does not replace or counteract Al3+ in activating the channel.
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“protoplasts isolated from the apical root cortex of two maize cultivars differing in Al resistance”
e6“La3+ was not able to replace or counteract with Al3+ in the activation of this channel”
Claim · model-written summary
Al applied in the whole-cell configuration elicits anion currents within 10 min in the resistant cultivar only.
- Material
- resistant cultivare2
- Treatment
- Al was applied to the protoplasts in the whole-cell configuratione2
- Outcome
- anion currents were elicited within 10 mine2
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“protoplasts isolated from the apical root cortex of two maize cultivars differing in Al resistance”
e2“When Al was applied to the protoplasts in the whole-cell configuration, anion currents were elicited within 10 min in the resistant cultivar only”
Claim · model-written summary
Cycloheximide does not affect the Al response.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“protoplasts isolated from the apical root cortex of two maize cultivars differing in Al resistance”
e7“Application of cycloheximide did not affect the Al response”
Claim · model-written summary
Anion-channel blockers strongly inhibit anion currents and exudation rates.
- Treatment
- anion-channel blockerse2
- Outcome
- anion currents as well as exudation ratese2
- Direction
- strongly inhibitede2
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“protoplasts isolated from the apical root cortex of two maize cultivars differing in Al resistance”
e2“In the presence of the anion-channel blockers, niflumic acid and 4, 4'-dinitrostilbene-2, 2'disulfonic acid, anion currents as well as exudation rates were strongly inhibited”
Claim · model-written summary
The channel is interpreted as activated through post-translational modifications.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“protoplasts isolated from the apical root cortex of two maize cultivars differing in Al resistance”
e7“Application of cycloheximide did not affect the Al response”
e3“suggesting that the channel is activated through post-translational modifications”
Claim · model-written summary
The anion channel is proposed to contribute to enhanced Al resistance by facilitating organic acid anion exudation.
- Outcome
- enhanced genotypical Al resistancee2
- Qualifier
- facilitating the exudation of organic acid anionse2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“protoplasts isolated from the apical root cortex of two maize cultivars differing in Al resistance”
e2“We propose that the Al-activated large anion channel described here contributes to enhanced genotypical Al resistance by facilitating the exudation of organic acid anions from the DTZ of the maize root apex”
The same questions in other papers
aluminium atom · molecular: metabolites · Zea mays (maize)Positive and negative results
7 papers in the same direction as this paper · 18 in the opposite direction
- negative
- negative
- negative
22 papers more in this group
See all 26 papers →cycloheximide · nutrient: content · Zea mays (maize)Results agree
2 papers in the same direction as this paper
- no effect
- negative
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.