Abstract
Plant roots are gravitropic, detecting and responding to changes in orientation via differential growth that results in bending and reestablishment of downward growth. Recent data support the basics of the Cholodny-Went hypothesis, indicating that differential growth is due to redistribution of auxin to the lower sides of gravistimulated roots, but little is known regarding the molecular details of such effects. Here, we investigate auxin and gravity signal transduction by demonstrating that the endogenous signaling molecules nitric oxide (NO) and cGMP mediate responses to gravistimulation in primary roots of soybean (Glycine max). Horizontal orientation of soybean roots caused the accumulation of both NO and cGMP in the primary root tip. Fluorescence confocal microcopy revealed that the accumulation of NO was asymmetric, with NO concentrating in the lower side of the root. Removal of NO with an NO scavenger or inhibition of NO synthesis via NO synthase inhibitors or an inhibitor of nitrate reductase reduced both NO accumulation and gravitropic bending, indicating that NO synthesis was required for the gravitropic responses and that both NO synthase and nitrate reductase may contribute to the synthesis of the NO required. Auxin induced NO accumulation in root protoplasts and asymmetric NO accumulation in root tips. Gravistimulation, NO, and auxin also induced the accumulation of cGMP, a response inhibited by removal of NO or by inhibitors of guanylyl cyclase, compounds that also reduced gravitropic bending. Asymmetric NO accumulation and gravitropic bending were both inhibited by an auxin transport inhibitor, and the inhibition of bending was overcome by treatment with NO or 8-bromo-cGMP, a cell-permeable analog of cGMP. These data indicate that auxin-induced NO and cGMP mediate gravitropic curvature in soybean roots.
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Claims 11
Claim · model-written summary
Horizontal orientation of soybean roots caused NO and cGMP to accumulate in the primary root tip.
- Taxon
- soybean
Glycine maxe0 - Treatment
- Horizontal orientation of soybean rootse1
- Outcome
- accumulation of both NO and cGMPe1
- Direction
- increaseinferrede1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“primary roots of soybean (Glycine max)”
e1“Horizontal orientation of soybean roots caused the accumulation of both NO and cGMP in the primary root tip”
Claim · model-written summary
NO accumulation in soybean roots was asymmetric, concentrating in the lower side of the root.
- Taxon
- soybeanGlycine maxe0
- Outcome
- accumulation of NOe2
- Direction
- asymmetrice2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“primary roots of soybean (Glycine max)”
e2“the accumulation of NO was asymmetric, with NO concentrating in the lower side of the root”
Claim · model-written summary
Removing NO with a scavenger or inhibiting NO synthesis reduced both NO accumulation and gravitropic bending in soybean roots.
- Taxon
- soybeanGlycine maxe0
- Treatment
- Removal of NO with an NO scavengere3
- Outcome
- NO accumulation and gravitropic bendinge3
- Direction
- reducede3
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“primary roots of soybean (Glycine max)”
e3“Removal of NO with an NO scavenger or inhibition of NO synthesis via NO synthase inhibitors or an inhibitor of nitrate reductase reduced both NO accumulation and gravitropic bending”
Claim · model-written summary
NO synthase and nitrate reductase may both contribute to the NO synthesis required for gravitropic responses.
- Taxon
- soybeanGlycine maxe0
- Gene
- NO synthase and nitrate reductasee4
- Outcome
- synthesis of the NOe4
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“primary roots of soybean (Glycine max)”
e4“both NO synthase and nitrate reductase may contribute to the synthesis of the NO required”
Claim · model-written summary
Auxin induced NO accumulation in root protoplasts and asymmetric NO accumulation in root tips.
- Taxon
- soybeanGlycine maxe0
- Treatment
- Auxine5
- Outcome
- NO accumulatione5
- Direction
- inducede5
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“primary roots of soybean (Glycine max)”
e5“Auxin induced NO accumulation in root protoplasts and asymmetric NO accumulation in root tips”
Claim · model-written summary
Gravistimulation, NO and auxin induced cGMP accumulation in soybean roots.
- Taxon
- soybeanGlycine maxe0
- Treatment
- Gravistimulatione6
- Outcome
- accumulation of cGMPe6
- Direction
- inducede6
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“primary roots of soybean (Glycine max)”
e6“Gravistimulation, NO, and auxin also induced the accumulation of cGMP”
Claim · model-written summary
Removal of NO inhibited the cGMP response in soybean roots.
- Taxon
- soybeanGlycine maxe0
- Treatment
- removal of NOe7
- Outcome
- responsee7
- Direction
- inhibitede7
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“primary roots of soybean (Glycine max)”
e7“a response inhibited by removal of NO or by inhibitors of guanylyl cyclase, compounds that also reduced gravitropic bending”
Claim · model-written summary
Inhibitors of guanylyl cyclase reduced gravitropic bending in soybean roots.
- Taxon
- soybeanGlycine maxe0
- Treatment
- inhibitors of guanylyl cyclasee7
- Outcome
- gravitropic bendinge7
- Direction
- reducede7
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“primary roots of soybean (Glycine max)”
e7“a response inhibited by removal of NO or by inhibitors of guanylyl cyclase, compounds that also reduced gravitropic bending”
Claim · model-written summary
An auxin transport inhibitor reduced asymmetric NO accumulation and gravitropic bending in soybean roots.
- Taxon
- soybeanGlycine maxe0
- Treatment
- an auxin transport inhibitore1
- Outcome
- Asymmetric NO accumulation and gravitropic bendinge1
- Direction
- inhibitede1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“primary roots of soybean (Glycine max)”
e1“Asymmetric NO accumulation and gravitropic bending were both inhibited by an auxin transport inhibitor”
Claim · model-written summary
Treatment with NO or 8-bromo-cGMP overcame the inhibition of gravitropic bending in soybean roots.
- Taxon
- soybeanGlycine maxe0
- Treatment
- treatment with NO or 8-bromo-cGMPe1
- Compound
- 8-bromo-cGMPe1
- Outcome
- the inhibition of bendinge1
- Direction
- overcomee1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“primary roots of soybean (Glycine max)”
e1“the inhibition of bending was overcome by treatment with NO or 8-bromo-cGMP, a cell-permeable analog of cGMP”
Claim · model-written summary
Auxin-induced NO and cGMP mediate gravitropic curvature in soybean roots.
- Taxon
- soybeanGlycine maxe0
- Compound
- NO and cGMPe1
- Outcome
- gravitropic curvaturee1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“primary roots of soybean (Glycine max)”
e1“auxin-induced NO and cGMP mediate gravitropic curvature in soybean roots”
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See all 15 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.