Genetic diversity of phytoplasmas identified in peach (Prunus persica) accessions at the Canadian Clonal Genebank.
Bibliographic record
Abstract
Peach [Prunus persica (L.) Bastch] is mainly cultivated in Canada in Ontario province (82% of national production). A variety of symptoms typical of a phytoplasma infection were observed some of the 83 P. persica accessions during June-August 2009 at the Canadian Clonal Genebank. PRU0430 (‘HW274’, from Canada), PRU0380 (‘GF305’ from France), PRU0334 (‘RedSkin’ from USA), PRU0155 (‘Harblaze’, from Canada) and PRU0375 (‘Babygold #5’, from USA) showed decline, leaf reddening, yellowing, shortening of internodes, witches’ broom and reduced fruit size; while ‘PRU0382’ (peach-almond ‘Kando’ from the Czech Republic) and PRU0445 (peach ‘HW271’ from Canada) exhibited peach rosette-like symptoms. Leaf samples from symptomatic and symptomless plants were collected and total DNA was extracted. Phytoplasma universal 16S rRNA primers, R16mF2/R1 and R16F2n/R2 and fU5/rU3 were used in nested PCR assays. R16F2n/R2 nested PCR products were obtained for ‘PRU0430’, ‘PRU0380’, ‘PRU0155’, ‘PRU0334’ and ‘PRU0375’; while fU5/rU3 PCR products were obtained for ‘PRU0382’ and ‘PRU0445’. Plants lacking symptoms yielded no PCR products. Amplicons were purified, cloned, and sequenced. BLAST analysis showed that R16F2n/R2 sequences (GU223903) were 99% identical to 16S rRNA phytoplasma sequences for group 16SrVII ‘Candidatus Phytoplasma fraxini’, while those from fU5/rU3 amplicons (GU223904) shared 99% identity with those of group 16SrI ‘Candidatus Phytoplasma asteris’. AluI, RsaI and MseI RFLP analysis yielded profiles consistent with those of phytoplasma in subgroups 16SrVII-A and 16SrI-B, respectively. To our knowledge, this is the first report of a 16SrI-related phytoplasma in peach in Canada, and the first world report of a 16SrVII-related phytoplasma strain identified in peach after a case in southern Italy.
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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 | 0.002 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.001 |
| 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 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".