Single-strain and consortium inoculations with plant-beneficial <i>Pseudomonas</i> spp. promote lettuce growth under field conditions
Bibliographic record
Abstract
ABSTRACT Plant-beneficial Pseudomonas spp. can promote plant growth by a wealth of mechanisms. Developing microbial inoculants encompassing multiple Pseudomonas strains (consortia) could represent an attractive solution to some of the problems encountered by single-strain inoculants, such as inconsistent rhizosphere colonization under field conditions. In this study, we evaluated the potential of Pseudomonas protegens B21-024 and Pseudomonas putida B21-029, inoculated alone or in combination, to promote lettuce growth under greenhouse and representative commercial field conditions. Plant growth metrics, including shoot fresh and dry weights, were used to evaluate plant growth promotion. In addition, unmanned aerial vehicle imaging was used to monitor plant growth in the field. Strain-specific primer-probe sets were also developed to study, using the quantitative polymerase chain reaction, the population dynamics of the two strains in rhizosphere soil. P. putida B21-029 and the Pseudomonas consortium significantly increased lettuce shoot fresh/dry weight under greenhouse conditions. In the field, only inoculation with P. protegens B21-024 and the Pseudomonas consortium promoted lettuce growth by significantly increasing shoot dry weight. Interestingly, the nitrogen-rich bacterial growth medium used to prepare the inocula played a role in the plant growth promotion achieved. Overall, the rhizosphere population of both Pseudomonas strains remained relatively stable during the growing season. However, the population of P. protegens B21-024 was significantly higher when it was co-inoculated with P. putida B21-029 than when inoculated alone, suggesting the existence of a beneficial relationship. These findings support the use of Pseudomonas consortia to promote the growth of leafy greens under field conditions. IMPORTANCE Some bacteria belonging to the genus Pseudomonas can establish mutually beneficial relationships with many crop species, resulting in disease suppression and/or plant growth promotion. These microorganisms show potential to replace, at least in part, synthetic fertilizers and pesticides in agricultural field settings. While some Pseudomonas strains have been shown to promote lettuce growth, successfully developing Pseudomonas consortia would have many advantages over single-strain inoculations, including better effectiveness and rhizosphere colonization. In this study, a consortium encompassing two Pseudomonas strains successfully promoted lettuce growth under greenhouse and field conditions. The nitrogen-rich bacterial growth medium used for the preparation of inocula contributed to the plant growth promotion achieved. Strain-specific molecular markers were also developed to monitor the abundance of each strain in rhizosphere soil throughout the growing season. The results obtained in this study indicate that the two Pseudomonas strains under study successfully colonized the lettuce rhizosphere.
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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 | 0.000 | 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".