Peroxidase and Pectin Methylesterase Activities in Cocoyam (<i>Xanthosoma sagittifolium</i> L. Schott) Roots upon <i>Pythium myriotylum</i> Inoculation
Bibliographic record
Abstract
Abstract Cocoyam (Xanthosoma sagittifolium) is an important source of energy food for humid and semihumid tropic populations and consists of three cvs distinguished by the colour of their flesh, their productivity and their root rot disease scores: one sensitive (white), one intermediate (red) and one resistant (yellow). Changes in peroxidase (POD; EC 1.11.1.7) and pectin methylesterase (PME; EC 3.1.1.11) activities from roots of the three cvs were examined by isoelectrofocusing (IEF), polyacrylamide gel electrophoresis (PAGE) and sodium dodecyl sulphate (SDS)‐PAGE upon inoculation with Pythium myriotylum. The evaluation of total POD activity shows the existence of a correlation between the sensitivity to P. myriotylum and POD activity. After 2 days of inoculation, POD activity of yellow cv. increased by 41.5%, while in the white and the red cvs the increase was only 13.4% and 7.5% respectively. In the soluble fractions of the resistant cv., the patterns of POD isozymes showed three new bands (Rf = 0.25; 0.38 and 0.85) and in ionically bound fraction, a new acidic (Rf = 0.2) specifically in inoculated root. The study of substrate specificity of POD with chlorogenic acid (C‐POD), ferulic acid (F‐POD) and indole acetic acid (IAA‐POD) showed an induction of C‐POD and F‐POD and a decrease in IAA‐POD in cocoyam roots after inoculation with P. myriotylum. Constitutively, ionically bound C‐POD and F‐POD activities were higher in roots of the yellow (11.6 and 11.7 EU/g Fw) than in those of the red (5.3 and 7.0 EU/g Fw) and the white (2.3 and 4.2 EU/g Fw) cvs. In addition, isoelectric‐focusing analysis of PME revealed an alteration of their profile correlated with inoculation. After inoculation, the appearance of a strong (pI: 9.7) and low (pI: 7.6) PME activities in the roots of yellow cv. were detected. Our findings suggest that POD and PME might be involved in the defence mechanism of cocoyam against P. myriotylum.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 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 source (direct Gemma or distilled Codex), 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".