Biological Control of Streptomyces sp. PR69 Against Phytophthora capsici and Its Growth-Promoting Effects on Plants

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

The author evaluated the biological control effects of Streptomyces sp. PR69 they isolated against Phytophthora capsica and its growth-promoting effects on plants. The research is interesting and the methods are sound and reasonable.

 

Introduction: The logical of this part is good, may I suggest the author expand the knowledge and researches background to support the gap and the reason why this research was carried out?

 

Materials and methods: Move Table S1 to the manuscript as Table 1.

More details of the methods are required. Particular the in vitro experiment, the growth experiment, with photos of the treatments.

 

Results: move Figure S1 to the manuscript,

Table 1, no statistics?

 

May I suggest the author use Figure to show the data of present Table 1.

 

I recommend the author move the supplementary figures to the context of the ms to support the results, with direct evidence.

 

The logical of Line 316 to 331 need to be improved.

 

Table 4. do you have data to support the positive / negative?

Figure 3. the legend need to be more clear. Could the author please give a bar for the petri dish with plants?

 

Discussion: Generally good, I suggest the author emphasize the key findings and novelty of present study first, then compare with other research. Please also explain why the strains present study used inhibit the growth of pathogen and improves the growth? The key mechanism involved.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

Dear authors,

I consider that the manuscript presents very interesting results on the biological control of Streptomyces sp. PR69 against Phytophthora capsici and its growth-promoting effects on plant; however, some remarks are made that could contribute to improve the final version.

Title

Lines 2-3. sp. PR69 should be not in italic. Avoid the dot at the end of the title. 

Introduction

Line 31. It is recommended to include the scientific name of the bell pepper.

Line 50. It should be Bacillus spp., and Streptomyces spp., some … 

Line 66. You mention “identify and characterize a strain isolated...”, however, I consider the objective must be open to more than one isolate even if at the end one of those analyzed is characterized.

Line 69. It should be bell pepper plants, because the scientific name of the species should be initialized before in the Introduction, as suggested.

Materials and methods

Line 73. Consider the possibility of matching the subtitles of Materials and Methods with those of Results.

Line 73. Avoid dots and the end of subtitles. Applied to the rest of the manuscript.  

Line 81. And should be not in italic. 

Line 102. I consider that in the Materials and Methods should not refer to the PR69 isolate because it advances results. Extend this suggestion to the rest of the manuscript. 

Line 116. It should be 7 mm … 

Lines 144-170. Please the units must be used taking into account the international system. Avoid minutes, hours, rpm. Use min, h, x g instead.

Line 212. Note that the scientific name of the species should be used in full only once in the body of the document, in addition to the figures and tables. Please, check this in the entire manuscript. 

Please, in general you should check that values are separated from the units except for the %.

Line 240. It should be only PDA.

Lines 251-253. You should include a sentence stating that a normality analysis of the data was performed before going on to the specific analyses performed.

Results

Line 264. A dot at the end of the sentence is missing. Check this aspect in the manuscript. 

Eliminate a blank row in table 4. 

Line 360. Only results should be given and interpretations should be left to the Discussion.

Discussion

Please, check because Ciénegas is writing to two different ways. 

The paragraphs in this chapter are very long, and that makes it difficult to convey the ideas that are trying to be conveyed. 

 

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

This study explores the biological control potential of Streptomyces sp. PR69, an actinobacterium isolated from the Cuatro Cienegas Basin in Mexico, against the plant pathogen Phytophthora capsici and its growth-promoting effects on plants. PR69-treated soil reduced P. capsici disease symptoms by 50% in bell pepper plants and increased plant survival and fresh weight compared to untreated controls. These studies support the capabilities of Streptomyces sp. PR69 as biocontrol agent. However, there are several areas that require improvement. The areas requiring improvement in this manuscript focus on clarity, rationale, and structure. There is a need for greater detail on experimental methodologies, including culture preparation, inoculum uniformity. Structural improvements involve splitting overly long paragraphs (e.g., L438–473, L488–538, L539–581) for readability and moving content better suited to the introduction (L402). Statistical analyses need detailed descriptions of data types, software, and assumptions (L251). Finally, the Ithenticate report of plagiarism is relatively high (25%) and after verification some sentences matched with other publications, although they were correctly cited, it is important to paraphrase and not copy directly the sentences.  These areas need to be improved before this study can be published. More detailed suggestions are provided:

L15 Remove “confirming its classification as a member of the genus”. Instead, write “identifying it as Streptomyces  through a phylogenetic analysis"

L21 How much did it increase compare to the control? Was it significant?

L47 Actually the most successful is plant resistance. Consider using other expression such as “more promising”, etc.

L57 consider starting the paragraph different from “Streptomyces”, since the previous paragraph started in the same way.

L62 Can you elaborate more on the environmental conditions that make The Cuatro Cienegas Basin a promising area for the discovery of microbial agents?

L66 What was the hypothesis of this research?

L77 Describe rationale behind using the International Streptomyces Project 2 (ISP2) culture medium? Why is this the optimal medium?

L79 Do these fungal strains have an accession number?

L86 Provide a rationale for the use of these specific plant cultivars

L92 how old were the fungal pathogen cultures? What kind of media was used to grow them?

L94 how were the Streptomyces cultures prepared? How was the inoculum uniform?

L99 “nine” phytopathogens.

L102 How many spores? Were they uniform?

L126 provide a rationale for using 11 different liquid and solid media. Why was the incubation 14 days?

L155 details on sequencing depth (e.g., coverage) are absent.

L157 what were considered low quality read?

L158 how was the assembly quality assessed?

L160 How was the phylogenetic analysis conducted? What parameters were used? Provide a list of the 81 genes used in the supplementary materials.

L172-210 provide some rationale for these test, instead of just citing each media used.

L245 How was Streptomyces inoculated? Drenching?

L248 how were conditions for plant grow? How were they water? How often? What about light conditions?

L249 What was the experimental design? What was the experimental unit? What was the criteria or scoring method used to evaluate disease symptoms?

L251 Describe the type of data analyzed (continuous, categorical) for each experiment. In addition, there is not mention of whether assumptions for the statistical tests (e.g., normality, homogeneity of variance) were checked and, if so, how? Mention the  software used for data analysis.

L333 was the three rooted? What was the outgroup?

L357 How much larger than controls?

L359 how much were the differences for weight, root length and secondary root development respectively?

L383 How and when the fresh weight was measured?

L389 Figure 4. What does each row of plants represents?

L402 The first two paragraphs could be in the introduction, as they provide the rationale for why the biocontrol agent were obtained from that particular area

L431 Are these Streptomyces strains isolated from the same area? Provide some context about these strains

L438-473 The paragraph is too long. Consider splitting

L488-538 The paragraph is too long. Consider splitting into multiple paragraphs

L539-581 The paragraph is too long. Consider splitting into multiple paragraphs

 

 

 

 

 

Comments for author File: Comments.pdf

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Round 2

Reviewer 3 Report

Comments and Suggestions for Authors

The authors have carefully addressed all the suggestions and implemented the recommended changes. Consider removing the white spaces in the manuscript before publication