Inoculation with Plant Growth-Promoting Bacteria Improves the Sustainability of Tropical Pastures with Megathyrsus maximus

Round 1

Reviewer 1 Report

Comments to the authors.

The manuscript titled ‘Inoculation with plant growth-promoting bacteria improves the sustainability of tropical pastures with Megathyrsus maximus’’ reports on a strategy to improve the strategy for sustainability of M. maximus pastures using PGPB. I have read the manuscript very carefully and found that it is a good piece of research work with a good set of data provided.

I have found, some limitations in the manuscript. However, in the current state, the manuscript is not acceptable and requires some corrections mentioned in the attached annotated file.

I highly recommend, kindly improve the English grammar of the manuscript. Some sentences are very poor written.

Recommendation:

I recommend accepting this manuscript for publication in the Journal Agronomy after major Revisions, because it is suitable for this journal.

Comments for author File: Comments.pdf

Author Response

Reply: Reviewer #1

General

Thanks a lot for finding our manuscript a good piece of research work with a good set of data provided and thanks for the contributions

Corrections (pointed in yellow in the PDF):

• Due to its good adaptation and biomass production and quality, maximus has been increasingly used in Brazil, because of its high nutritional value and good palatability

Reply: The sentence was rephrased. “Megathyrsus maximus has been increasingly used in Brazil, as it shows good adaptation to all edaphoclimatic conditions and high biomass production with good nutritional value and palatability.”

 

• In general, this model has lower productivity because of poor investments in pastures, leading to degradation that results in low forage quality and capacity of cattle support, and thus increasing pressure on new areas of native vegetation

Reply: The sentence was rephrased. “However, extensive growth is majorly associated with poor investments in fertilizers and soil conservation, leading to pasture degradation and decreased capacity of cattle support, altogether increasing the pressure to move to new areas of native vegetation.”

 

• DYGS

Reply: We included Dextrose Yeast Glucose Sucrose.

 

• Six

Reply: We include “six seeds”

 

• What about the other nutrients?

Reply: Sorry, the citation referred to the nutrient solution containing all nutrients. We clarified that.

 

• Previously submitted

Reply: Sorry, you are correct. We changed to first submitted.

 

• Root morphological traits

Reply: Throughout the whole manuscript we changed to root growth traits.

 

• Lettering missing – Table 1 and 2

Reply: We only included lettering in the parameters that showed statistical difference. We made it more clear now in the footnote.

 

• CV, LSD

Reply: We ask to leave with letter indicating statistical difference, because if we include the LSD that it is redundance to include the letter, and the readers will have to do the calculations. Therefore, we left the letter indicating the treatments that were different, we included the footnote indicating that traits without letter were not statistical difference, we have the p value for each traits and we left the CV, as it indicates how variable were the measurements of each trait, as based in literature some show high variability.

 

• At least one nutrient

Reply: We rephrased to one or more nutrients.

 

• Table citation in the discussion

Reply: We avoided including table and figure citations in the discussion section. To make it more clear, we included that we are referring to the results from our study.

 

• The great majority of the pastures worldwide are of grasslands and, unfortunately, a great percentage in some degree of degradation

Reply: We rephrased. Grasslands compose the great majority of pastures worldwide, but unfortunately, a significant percentage of them are in some stage of degradation.

 

• The results were highly indicative of the feasibility of quantitative and qualitative improvement of pastures of maximus via inoculation with PGPR, but also pointed out the need for searching for the best host-bacterium combinations.

Reply: We rephrased. “Our results have shown the feasibility of improving biomass and quality of pastures of M maximus by inoculation with PGPB. However, our results also indicate the need to search for the best plant genotype host x bacterium combinations”.

 

• We reviewed the English throughout the manuscript.

 

 

 

 

 

Reviewer 2 Report

Manuscript ID: agronomy-2159098

Type: Article

Title: Inoculation with plant growth-promoting bacteria improves the sustainability of tropical pastures with Megathyrsus maximus

Recommendation: Minor Revision

 

Here, the authors have evaluated the inoculation effect of beneficial PGPRs strains on different cultivars of Megathyrsus maximus. Following bacterial inoculation, they have observed and concluded that applied bacterial strains significantly enhanced the shoot dry weight (SDW), and macro and micronutrients accumulated in shoots and root traits. Overall, the manuscript is good and very suitable for the journal agronomy.

1.     The title is eye-catching and interesting.

2.     This article is written very well and may helpful for readers around the globe.

3.     Abstract is good and to the point.

4.     Introduction section is written very well. However, there is lack of literatures regarding the mechanistic insights and growth promotion mechanisms of PGPR. Authors are requested to elaborate the role of PGPR on plants and mechanisms of growth promotion. For the growth mechanisms of PGPR, authors may check the following published literatures:

https://doi.org/10.1016/j.chemosphere.2022.133843

https://doi.org/10.3390/biology10111149

5.     The material and methods section has described in detailed. However, there is a lack of assessment of growth promoting traits. It is fact that soil beneficia bacteria helps in the growth augmentation of crop plants by producing/synthesizing various growth regulating active biomolecules. The authors are requested to provide the data for the same. Thank you.

6.     Results and discussion are appropriately discussed. The overall manuscript is good. However, there are some errors have been observed which is needed to improve before publication of the article. 

7.     Tables and figures are nicely presented. Table 1 is very good appropriately and statistically analysed. In figure 1, panels A, D and E did not have any statistical analysis. Figure 2 and 3 (SEM examination) are very neat and clean.

8.     Conclusion section is good. However, I think it needs revision/modifications. It seems like the authors have pasted the contents from the abstracts section. I am sorry so for these comments. But, the conclusion section needs refining before the final publication of this article.

Author Response

Reply: Reviewer #2

 

General

Thanks a lot for finding our manuscript a good piece of research work with a good set of data provided and thanks for the contributions

 

Recommendation: Minor Revision

 

Thanks a lot for the time taken to review our manuscript and mainly for the contributions that improved the paper.

 

Corrections

 

1. The title is eye-catching and interesting.

Reply: Thanks a lot.

 

2. This article is written very well and may helpful for readers around the globe.

Reply: Thanks a lot.

 

3. Abstract is good and to the point.

Reply: Thanks a lot.

 

4. Introduction section is written very well. However, there is lack of literatures regarding the mechanistic insights and growth promotion mechanisms of PGPR. Authors are requested to elaborate the role of PGPR on plants and mechanisms of growth promotion. For the growth mechanisms of PGPR, authors may check the following published literatures:

https://doi.org/10.1016/j.chemosphere.2022.133843

https://doi.org/10.3390/biology10111149

Reply: We reorganized the introduction section to make it clearer. And we included the mentioned references.

 

5. The material and methods section has described in detailed. However, there is a lack of assessment of growth promoting traits. It is fact that soil beneficia bacteria helps in the growth augmentation of crop plants by producing/synthesizing various growth regulating active biomolecules. The authors are requested to provide the data for the same. Thank you.

Reply: The traits that we analyzed were ten root growth traits, biomass production, 11 nutrients accumulated in tissues and photographies in scanning electron microscope. We discuss the possible mechanisms in the discussion section. We tried to make it more clear now.

 

6. Results and discussion are appropriately discussed. The overall manuscript is good. However, there are some errors have been observed which is needed to improve before publication of the article. 

Reply: We reviewed all the paper to correct English mistakes.

 

7. Tables and figures are nicely presented. Table 1 is very good appropriately and statistically analysed. In figure 1, panels A, D and E did not have any statistical analysis. Figure 2 and 3 (SEM examination) are very neat and clean.

Reply: Thanks a lot.

 

8. Conclusion section is good. However, I think it needs revision/modifications. It seems like the authors have pasted the contents from the abstracts section. I am sorry so for these comments. But, the conclusion section needs refining before the final publication of this article.

Reply: We re-wrote the conclusions, also adding other reviewer´comments. And we changed the title to concluding remarks, as we propose new actions for the future.

 

We reviewed the English throughout the manuscript.

Reviewer 3 Report

Comments on the inclusion of native strains and the evaluation of consortia are indicated in ms highlighted in yellow. 

Comments for author File: Comments.pdf

Author Response

Reply: Reviewer #3

 

General

Thanks a lot for the contributions and the time reviewing the manuscript.

 

Corrections:

 

 

• Jacq

Reply: Sorry, it is now correct

 

• Why not a consortium of all strains?

Reply: Inoculants carrying one species bring advantages in terms of production. Different species require different nutrients for maximum growth, show differences in time of duplication, usually one species can dominate the inoculant. This is an industrial explanation. In the case of our study, as there was absolutely no information about the performance of different bacterial species and their interaction with different plant genotypes, this represents a first step of research, that was to investigate the performance, to find the best combinations, etc. Therefore, we needed inoculation with single species. Now, with the identification of the best combinations of plant genotype and bacterial species, the next step will be to go to field experiments, where we can also try combinations of inoculants. But prepared in different inoculants.

 

• What about the native PGPB? Also Including evaluations of native PGPB strains

Reply: Thanks for asking that, because this is a very important point that we have not noted that was missing. We have now included that all strains are native PGPB, except for Rhizobium tropici CNPSo 103, that is from Colombia, that has been successfully used in inoculants for the common bean crop in Brazil for more than two decades. This point is so important that we also included this observation of importance of selecting elite strains within the native population as a last sentence in the Concluding remarks.

 

• Evaluation of consortia will be very interesting

Reply: Yes, we added this to the concluding remarks.

 

We reviewed the English throughout the manuscript.

Reviewer 4 Report

Dear author:

Please consider the comments. 

Sincerely,

Comments for author File: Comments.pdf

Author Response

Reply: Reviewer #4

 

General

Thanks a lot for the contributions and the time reviewing the manuscript.

 

Corrections:

 

Specific comments:

 

• L12: Superscript (5) not found in the author list

Reply: Sorry, it is now corrected

 

Introduction:

 

• The background of this study is not clearly expressed. rewrite please!

Reply: We reorganized the introduction, trying to make the background information stronger and clearer.

 

• L72-76: delete some references

Reply: There were three references. We replaced to of them by a new one and left the other one.

 

Materials and Methods:

• This section is not clear, the author conducted into two experiments? If yes, please add a paragraph to introduce each experiment.

Reply: We believe that it is now clear that there were two experiments.

 

• L98: “then mixed to a final concentration” This sentence is not clear, should be expressed clearly.

Reply: We explained that they were mixed to result in a final concentration

 

• L98: change “CFU (colony forming units)” to “colony forming units (CFU)”

Reply: Corrected.

 

• L122-123: The experimental design was a completely randomized with six replicates.

Reply: Corrected.

 

• L142: Please add the full name of FAA

Reply: Full name added.

 

• L172: Treatments and plant growth conditions

Please add the method for shoot dry weight analyzed.

Reply: Description included.

 

Results:

• L196: delete “root dry weight” and “root volume”

L197: delete “root area” and “total root length”

L197-198: delete “number of branches”

L201: delete “root hair incidence”

L206-207: delete “root mean diameter”

Reply: As we are dealing with ten root traits, we deleted the names of the parameters, as asked. However, it was then very difficult, because the parameters were explained in the material and methods section. Therefore, we ask to leave the full name the first time that we mention the trait in the results section.

 

• Table 1: Please, delete the full name of all parameters, and add the footnote.

Reply: Again, we ask to leave the full name in the title, not as footnote, it is clearer.

 

 

• Table 1 and 2: Replace the information of “%CV” by “standard error of the means (SEM)”

Reply: We included the values of CV because we estimated CV, not standard error of the means

 

• Table 2: Please space p value of Quênia

Reply: Corrected

 

Discussion:

 

• L309: delete “plant growth-promoting bacteria”

Reply: Deleted.

 

• L313-315: Please use the abbreviation to replace the full name.

Reply: We used the abbreviation.

 

• L384: change “For example,” to “Previously,”

Reply: Changed.

 

• L392-393: Please add the reference.

Reply: We re-phrased the sentence.

 

• L427, 430: change “personal communication” to “data unpublished”

Reply: Changed.

 

We reviewed the English throughout the manuscript.

 

Round 2

Reviewer 1 Report

The authors thoroughly revised the manuscript, now manuscript can be published

Author Response

Thanks a lot for accepting the changes made and confirming that the manuscript can be accepted for publication

Reviewer 4 Report

Dear author,

 Your responded are well to the review comments.  However, the manuscript has still many errors.

Sincerely,

Author Response

We have gone throughout the whole manuscript and reviewed the English. We also submitted the manuscript to an English professor. We believe that there now there are no errors. Thanks for accepting the changes made in the first round of review