A New Threat to Limber Pine (<i>Pinus flexilis</i>) Restoration in Alberta and Beyond: First Documentation of a <i>Cronartium ribicola</i> Race (<i>vcr4</i>) Virulent to <i>Cr4-</i>Controlled Major Gene Resistance
Bibliographic record
Abstract
The coevolution of virulence reduces the effectiveness of host resistance to pathogens, posing a direct threat to forest species and their key ecosystem functions. This is a threat to limber pine ( Pinus flexilis), an endangered species in Canada due to rapid decline mainly driven by white pine blister rust caused by Cronartium ribicola. We present the first report of a new, virulent race of C. ribicola (designated vcr4) that overcomes limber pine major gene ( Cr4) resistance (MGR). Field surveys found that three parental trees (pf-503, pf-508, and pf-2015-0070) were cankered with white pine blister rust in Alberta, but their progenies showed MGR-related phenotypic segregation postinoculation with an avirulent race of C. ribicola ( Avcr4). Genotyping of their progenies using Cr4-linked DNA markers and a genome-wide association study provided additional support that these cankered parental trees had Cr4-controlled MGR. To confirm the presence of vcr4, aeciospores were collected from the cankered pf-503 tree to inoculate resistant seedlings that had survived prior inoculation using the Avcr4 race, as well as seedlings of two U.S. seed parents, one previously confirmed with MGR ( Cr4) and one without MGR, respectively. All inoculated seedlings showed clear stem symptoms, confirming that the virulent race is vcr4. These results provide insights into the evolution of C. ribicola virulence and reinforce caution on deployment of Cr4-controlled MGR. The information will be useful for designing a breeding program for durable resistance by layering both R genes with quantitative trait loci for resistance to white pine blister rust in North America.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| 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".