Variability and mechanism of Saskatoon disease response to Entomosporium mespili
Bibliographic record
Abstract
'Entomosporium' leaf and berry spot, is a serious disease of saskatoon (Amelanchier alnifolia Nutt.). The objectives of this study were to assess the variability of saskatoon disease response to Entomosporium mespili, and to investigate the structural mechanisms of host resistance. Cultivars of saskatoon were characterized for incidence and severity of 'Entomosporium' leaf and berry spot. The cultivars Parkhill, Regent and Success showed consistently lower values for the incidence and severity of fungal sporulation on leaves and fruit. Variation in leaf disease response to 'E. mespili' was observed among self- and cross-pollinated seedling populations derived from saskatoon cultivars. Population means for leaf acervuli number ranged from 63.4 for seedlings of Honeywood to 237.5 for seedlings of Smoky. Plants with resistance to leaf spot were identified among self-pollinated populations derived from saskatoon cultivars; as well as three other species of 'Amelanchier'. Population means for leaf acervuli number ranged from 2.0 for 'A. intermedia' to 134.8 for 'A. fernaldii'. Scanning electron microscopy was used to elucidate the infection process of 'E. mespili' on leaves of saskatoon. Conidiospore germination occurred rapidly on leaves of two cultivars, usually by the extrusion of a single major germ tube. Spore penetration of the leaf cuticle involved appressoria, formed at germ tube termini or directly below the germinating spore. Sub-spore appressoria were most common and resulted in the early formation of leaf acervuli. At 2 days post inoculation, 43% of germinating conidiospores had penetrated the leaf surface of Buffalo, compared with 12% on leaves of Success. Pre- and post-infectional structural defense mechanisms were observed in inoculated leaves of saskatoon cultivars. Cuticle thickness was uniform across resistant and susceptible cultivars, but differences in leaf thickness and anatomy appeared to be important. Papillae composed of suberin or callose were formed at sites along the adaxial epidermal layer. In leaves of resistant cultivars, the formation of suberin deposits in palisade mesophyll cells appeared to confine fungal activity to epidermal cells. Suberization of mesophyll cells at the periphery of the lesion sequestered hyphae and limited the number of sporulation sites on the leaf surface.
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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 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| 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) | 0.001 | 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".