Molecular and morphological characteristics of<i>Apiosporina morbosa</i>, the causal agent of black knot in<i>Prunus</i>spp.
Bibliographic record
Abstract
Thirty isolates of Apiosporina morbosa, which were isolated from wild chokecherry (Prunus virginiana), an ornamental cultivar of chokecherry with purple foliage (P. virginiana ‘Shubert Select‘), and domestic plum (Prunus domestica), were compared for morphological and molecular characteristics, using culture techniques and data from internal transcribed spacers (ITS) I and II, restriction fragment length polymorphisms (RFLP), and sequence-related amplified polymorphism (SRAP) analyses. Strains of A. morbosa grew as olive-green colonies that changed in about 2 weeks to a dark-brown colour. Cultures produced single- or two-celled and cylindrical conidia with tapering ends. Conidia had a mean size of 4.51 μm × 10.97 μm. The overall colony and conidial morphology in cultures of the A. morbosa isolates was generally similar to that of an isolate of Cladosporium herbarum. Pseudothecia were globose and produced clavate asci with unequally two-celled and club-shaped ascospores having mean sizes of 6.68–7.37 μm × 16.42–16.78 μm. RFLP markers produced by endonucleases DdeI, Bst98I, and VspI in the ITS region differentiated the pathogen isolates from other gall-associated fungi, but no difference was observed among the A. morbosa isolates, using these markers. The sequences of the ITS region had >99% similarity among 30 isolates of A. morbosa, and a total of eight unique genotypes were found, based on ITS sequence alignment. The most common genotype was manifested in 21 of 30 A. morbosa isolates, based on the ITS sequences. Three A. morbosa isolates had an identical sequence to that of an isolate of C. herbarum. A comparison with an isolate of Cladosporium cladosporioides showed that A. morbosa differed from C. cladosporioides by 3%, based on ITS sequences. SRAP analysis detected 18 unique genotypes and a high genetic diversity (H = 0.256) among 25 isolates of A. morbosa. The pathogen population isolated from wild chokecherry produced more unique genotypes and higher genetic diversity (H = 0.283) than the population from ‘Shubert Select’ (H = 0.165). However, an exact test indicated no differentiation between these two populations (P = 0.334) with a gene flow rate of 4.28. Most of the isolates from ‘Shubert Select’ were clustered in a subgroup in a phylogenetic dendrogram. Phylogenetic analysis of ITS sequences of the A. morbosa isolates in our study and related taxa extracted from GenBank revealed that A. morbosa had the closest genetic distance with Cladosporium spp.
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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 | 0.000 |
| 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 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".