MAKING SURE HUNGRY PLANTS GET FED: THE DUAL-TARGETED PURPLE ACID PHOSPHATASE ISOZYME AtPAP26 IS ESSENTIAL FOR EFFICIENT ACCLIMATION OF ARABIDOPSIS THALIANA TO NUTRITIONAL PHOSPHATE DEPRIVATION
Bibliographic record
Abstract
Acid phosphatases (APases; E.C. 3.1.3.2) catalyze the hydrolysis of phosphate (Pi) from Pi monoesters and anhydrides within the acidic pH range.Induction of intracellular and secreted purple acid phosphatases (PAPs) is a widespread plant response to nutritional Pi-deficiency.The probable function of intracellular APases is to recycle Pi from expendable intracellular organophosphate pools, whereas secreted APases likely scavenge Pi from the organically bound Pi that is prevalent in most soils.Although the catalytic function and regulation of plant PAPs have been described, their physiological function in plants has not been fully established.Recent biochemical and proteomic studies indicated that AtPAP26 is the predominant intracellular (vacuolar) and a major secreted purple APase isozyme upregulated by Pi-starved (-Pi) Arabidopsis thaliana.The in planta function of AtPAP26 was assessed by molecular, biochemical, and phenotypic characterization of a homozygous Salk T-DNA insertion mutant.Loss of AtPAP26 expression resulted in the elimination of AtPAP26 transcripts and 55-kDa immunoreactive AtPAP26 polypeptides, correlated with a 9-and 5-fold decrease in extractable shoot and root APase activity, respectively, as well as a 40% reduction in secreted APase activity of -Pi seedlings.The results corroborate previous findings implying that AtPAP26 is: (i) the principal contributor to Pi starvation inducible APase activity in Arabidopsis, and (ii) controlled post-transcriptionally mainly at the level of protein accumulation.Total shoot free Pi level was about 40% lower in -Pi atpap26 mutants relative to wild-type controls, but unaffected under Pisufficient conditions.Moreover, shoot, root, inflorescence, and silique development of the atpap26 mutant was impaired during Pi deprivation, but unaffected under Pi-replete conditions, or during nitrogen or potassium-limited growth, or oxidative stress.The results suggest that the hydrolysis of Pi from organic-phosphate esters by AtPAP26 makes an important contribution to Pi-recycling and scavenging in -Pi Arabidopsis.iii Co-
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".