Abstract
ABSTRACT Surprisingly little is known about molecular mechanisms by which nitrogen (N) availability acts to modulate the growth of forest trees. To address this issue, differential display was used in conjunction with filter‐based arrays to identify 52 partial cDNA clones that were significantly regulated within days in response to limiting or luxuriant levels of NH 4 NO 3 fertilization in Populus trichocarpa Torr. & Gray × deltoides Bartr. ex Marsh. A subset of these cDNAs also demonstrated shifts in expression patterns in stem‐girdled trees, a manipulative physiology technique that disrupts phloem transport. Stem girdling also induced changes in glutamine and asparagine pools which were correlated with the observed changes in expression profiles for these genes. The identity of these genes provides insight into biochemical processes that are altered by N availability in poplar. Carbon–nitrogen interactions appear to figure prominently in the N‐response. The gene expression data suggest that N availability modulates the partitioning of C and N resources into metabolic fates that have the potential to alter both wood quality and quantity, including synthesis of vegetative storage proteins, cell wall components, and terpenoids.
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Claims 5
Claim · model-written summary
Nitrogen fertilization regulated 52 partial cDNA clones.
- Taxon
- Populus trichocarpa Torr. & Gray × deltoides Bartr. ex Marsh
Populus trichocarpae0 - Treatment
- limiting or luxuriant levels of NH 4 NO 3 fertilizatione0
- Outcome
- partial cDNA clonese0
- Value
- 52e0
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“identify 52 partial cDNA clones that were significantly regulated within days in response to limiting or luxuriant levels of NH 4 NO 3 fertilization in Populus trichocarpa Torr. & Gray × deltoides Bartr. ex Marsh”
Claim · model-written summary
Stem girdling shifted expression of some nitrogen-responsive cDNAs.
PopulusNot reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“A subset of these cDNAs also demonstrated shifts in expression patterns in stem‐girdled trees”
t0“poplar”
Claim · model-written summary
Girdling changed glutamine and asparagine pools.
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Stem girdling also induced changes in glutamine and asparagine pools”
t0“poplar”
Claim · model-written summary
Changes in amino acid pools correlated with gene expression changes.
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“which were correlated with the observed changes in expression profiles for these genes”
t0“poplar”
Claim · model-written summary
Expression data suggested nitrogen availability modulates carbon and nitrogen resource partitioning.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The gene expression data suggest that N availability modulates the partitioning of C and N resources into metabolic fates”
t0“poplar”