Genetic diversity and colonization patterns of Onnia tomentosa and Phellinus tremulae (Hymenochaetaceae, Aphyllophorales) in the boreal forest near Thunder Bay, northwestern Ontario
Bibliographic record
Abstract
Forest health is impacted greatly by fungi, particularly those that cause disease in living trees. By examining genetic diversity within populations of pathogenic fungi and their patterns of colonization it is possible to gain a greater understanding of host-pathogen interactions. Two common pathogens in the boreal forest are Onnia tomentosa, causal agent of a root-rot disease in spruce known as stand opening disease, and Phellinus tremulae, causal agent of white heart rot in stems of trembling aspen. Both fungi are members of the Hymenochaetaceae in the Basidiomycota. \nTwo black spruce (Picea mariana) plantations located north of Nipigon were examined for Onnia tomentosa. Spatial coordinates of 124 basidiomata were taken, and the basidiomata collected from plots that had received different commercial thinning treatments. Using extracted DNA from each of the basidiomata, it was possible to measure genetic diversity and consequently genet size. One hundred and sixteen genetically distinct individuals were found suggesting that the majority of the basidiomata represented unique genets. The distribution pattern was mapped. Stand thinning appears to negatively impact colonization of spruce by O. tomentosa compared with that observed in unthinned control stands. \nIn an ancillary study, a stand of trembling aspen (Populus tremuloides) located at Silver Mountain (74 km SW of Thunder Bay) was examined for Phellinus tremulae. Four infected trees were harvested and each stem cut into 50 cm sections with the top 5 cm from each section removed as a cookie. From each cookie, isolations of P. tremulae were made onto agar media and somatic compatibility techniques were utilized to determine size and distribution of genets in each tree. Two trees contained two genets of P. tremulae, one tree contained a single genet, while the remaining tree failed to yield any isolations of P. tremulae at all.
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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) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| 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".