Data from: Plant host identity and soil macronutrients explain little variation in sapling endophyte community composition: is disturbance an alternative explanation?
Bibliographic record
Abstract
1. Bacterial endophytes may be fairly host specific; nonetheless, an important subset of taxa may be shared among numerous host species forming a community-wide core microbiome. Moreover, other key factors, particularly the supply of limiting macronutrients and disturbances, may supersede the importance of host identity. 2. We tested the following four non-mutually exclusive hypotheses: 1. The Host Identity Hypothesis: endophytes vary substantially among different host plant species. 2. The Core Microbiome Hypothesis: a subset of microbial taxa will be shared among all host plant species. 3. The Soil Resource Supply Hypothesis: endophytes vary substantially among habitats with experimentally elevated levels of macronutrients. 4. The Disturbance-Disruption Hypothesis: disturbances created by the periodic application of antibiotics structure bacterial endophyte communities. 3. We tested these hypotheses by characterizing endophytes using high-throughput sequencing among seedlings of five phylogenetically diverse tree species nested within a long-term, full factorial nitrogen, phosphorus, and potassium soil fertilization experiment. We artificially disturbed one of our focal species by applying antibiotics every 10-14 days for 29 months within the soil (N,P,K) fertilization experiment. 4. While we detected a significant effect of host identity and soil nutrient additions, together they explained little variation in endophyte community composition (< 10%). We found unequivocal evidence for a core microbiome shared by all species. Specifically, we found nine OTUs were present among 95% or more of all control saplings, representing a third of the total reads. These bacterial taxa belonged to the Actinobacteria. 5. In contrast, disturbance (antibiotics) explained more endophyte variation than all nutrient addition combinations combined and twice the variation explained by host identity for all five tree species. Synthesis: Our results challenge the idea that host identity is a primary filter shaping bacterial endophyte communities; this suggests that many of the same bacterial taxa occur inside plant hosts even if those host plants are phylogenetically diverse. Moreover, we documented a distinct core microbiome shared among our five focal tree species. Finally, we found that disturbance was an important driver of microbial community composition, which parallels the importance of disturbance in other areas of community ecology.
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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 | 0.002 | 0.006 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.001 | 0.002 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.104 | 0.039 |
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".