Protein-Based Biostimulants to Enhance Plant Growth—State-of-the-Art and Future Direction with Sugar Beet as an Example

Round 1

Reviewer 1 Report

In this paper, the authors conducted a very interesting literature research regarding plant based biostimulants and analyse their effects based on a previously published case study. The manuscript structure is good and all statements are based on sound previous research. The manuscript is accepted as it stands right now, however, there are some notes to be taken into account:

L33: the word 'originates' should be written as 'originate'

L85-86: Restrictions of the use of animal-based biostimulants have been established from EU and they have to be mentioned. Please check EU regulation No. 354/2014

L139: Consider replacing the word 'also' with the word 'Furthermore"

L247-248: Re-write this sentence because there is no clear meaning

Table 3-Figure 2. Is there any explanation why plant height, total fresh weight and plant canopy area are decreased when PPBs are applied at concentrations above 5 g/kg? Consider writing somthething about this.

Author Response

Dear Reviewer,

We thank you very much for your comments on our manuscript. I herewith attached a point-to-point response to the questions you raised.

Kind regards.

Jolayemi

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments during the first round of peer review of the manuscript "Protein-based biostimulants to enhance plant growth – state-of-the-art and future direction with sugar beet as a case study" (authors Okanlawon Lekan Jolayemi, Ali H Malik, Tobias Ekblad, Kenneth Fredlund, Marie E. Olsson, Eva Johansson) submitted to the journal Agronomy MDPI:

1) This manuscript considers the current state of research on protein-based biostimulants and the prospects for the future development of this area of ​​research.

Certainly, this manuscript will be of interest to potential readers.

In general, this manuscript can be recommended for publication in the journal Agronomy MDPI.

2) At the same time, there are a number of aspects in the manuscript that could be improved.

3) The question arises about the categorization of the product under study.

The authors write that the active ingredients may increase resistance to biotic stress.

Does it mean that they are resistance inducers or even pesticides in this case?

Going further, the definition of biostimulants given in the manuscript bears a certain resemblance to the definition of plant growth regulators.

In this regard, are the PBB products considered by the authors still biostimulants or growth regulators, or both?

Thus, it is necessary to give a clearer justification for the categorization of the products studied in the manuscript.

4) Certainly, the mention of the need for future research (line 27) would be more appropriate for use not in the abstract, but in the Conclusion section (and this is already there to a certain extent).

5) It is necessary to clarify in more detail how biostimulants reduce the use of agrochemicals in agriculture, and which agrochemicals (lines 36-37).

6) What are the unknown aspects in question (line 44)?

In this regard, it would be useful for the manuscript to discuss the concept of emergence for biostimulants, which is discussed in a number of articles.

7) Clarification is needed for "climate-smart agriculture" (line 46).

8) It is necessary to provide more information about the social and economic aspects of the products in question.

9) It is necessary to attract more related articles and reviews to discuss and compare concepts.

10) If there are unmentioned in this manuscript and previously published articles/materials of the authors of this manuscript that are close to the subject of this manuscript, then it is necessary to discuss and cite these.

11) It would be desirable to double-check and clarify the reliability of the results in the table and figure.

Author Response

Dear Reviewer,

Thank you for your constructive comments on our manuscripts. I hereby attached a point-to-point response for your perusal. 

Kind regards.

Jolayemi

Author Response File: Author Response.pdf

Reviewer 3 Report

Thanks to the authors for providing this study.

This study provides practical information on: “Protein-based biostimulants to enhance plant growth – state-of-the-art and future direction with sugar beet as a case study”.

Mian comment: I see adding more studies on the applications of PBBs on sugar beet, because what is found in this study is not enough to make this plant a case study, or in the event that there is not a lot of research on sugar beet, I see changing the title of the research so that it is general about the uses and applications of PBBs and not a case study About sugar beet. However, please answer the following comments:

·       keywords: Add sugar beet to keywords.

·       Add to 2. Protein-based biostimulants:

-       The economic efficiency of extracting Protein-based biostimulants from natural materials and practical experiments that have been applied.

-       Add a paragraph on the efficiency of using Protein-based biostimulants compared to the use of similar biological compounds, as well as with chemical compounds and fertilizers; Citing appropriate recent references.

·       This paragraph (3.1 Hydrolyzed Wheat Gluten (HWG)) needs more expansion, supported by appropriate references, especially with regard to its agricultural uses.

·       In Paragraph: 3.2 Potato Protein (PP)

·       Is it possible to add some studies on the use of potato juice in agriculture and what results have been reached? Of course, other than sugar beet (which is the subject of the study), So that it is general and brief.

·       This paragraph (4. Biostimulating effect of HWG and PP; a case study on sugar beet) needs to add a lot of studies and references about the effect of using PBBs on the nutritional value of sugar beet, especially the sugar content, which is the most important characteristic of sugar beet cultivation. Because in this study, only the effect of PBBs on morphological and productive traits was mentioned.

Thanks

Author Response

Dear Reviewer,

We thank you for your positive comments on our manuscript.

I herewith attach a point-to-point response to the questions raised.

Kind regards.

Jolayemi

Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

Definitely, even after optimization, this manuscript needs conceptual improvement and deeper revision as a whole.

Not all recommendations from the first round of peer review have been implemented.

It is necessary to consider ALL the comments from there again and conduct a deeper analysis and discussion in the context of ALL the comments of the reviewer.

In addition, there are a number of additional remarks and comments.

What is the deep scientific meaning of Table 2?

It is absolutely formalistic and completely non-informative in essence.

It is necessary to provide specific details and information characterizing «the way for a more resilient use of natural resources» (lines 281-282) and convincing evidence that «Studies demonstrating that protein-based biostimulants (PBBs) can be environmentally sustainable products» ( line 298).

It is necessary to clarify, refer to and discuss in more detail the first publications on protein-based biostimulants.

It is necessary to clarify and more thoroughly substantiate the conceptual originality and novelty of this manuscript in comparison with other previously published works in this area of ​​research.

The authors of the manuscript work in organizations in Sweden.

Therefore, it is necessary to discuss the Legislation and Regulatory Framework for biostimulants in general in Sweden, compared with the regulation in Europe, the USA and China.

The same is necessary for protein-based biostimulants, in particular.

In general, the manuscript should be significantly revised in order to ideally meet the level and requirements of the target high-ranking journal Agronomy MDPI, which belongs to the first quartile, JCR - Q1 (Agronomy) indexed within Scopus and SCIE (Web of Science).

Author Response

Dear Reviewer,

We are really grateful for your constructive contributions and efforts to make our manuscript better. We are very sorry for not properly addressing your comments in the first round as it came quite late than other comments. 

Having said that, we have now critically looked at each point you raised and we have tried to answer every question and followed your advice and comments. we hope you are satisfied with this new revision. Thank you and best regards. 

Lekan

Author Response File: Author Response.pdf

Reviewer 3 Report

Thanks for Authors

Author Response

Dear Reviewer,

Thank you and best regards.

Lekan Jolayemi