Effect of Nitrogen Fertilizer on Capsaicinoids and Related Metabolic Substances of Dried Chili Pepper Fruit

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

Dear author,

 

Your manuscript addresses an interesting topic. However, some aspects of its structure and presentation need to be included.

 

Kind regards 

Comments for author File: Comments.pdf

Author Response

Thank you very much for your positive feedback on our manuscript. Undoubtedly, these comments are valuable and very helpful in revising and improving our manuscript. In the attachment, we would like to answer the questions you mentioned and provide a detailed explanation of the changes made to the original manuscript. Please refer to the attachment.

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

The paper entitled “Effect of Nitrogen Fertilizer on Capsaicinoids and Related Metabilic Substances of Dried Chilli Pepper Fruit” reports the results of an investigation, having the objective to evaluate the effects of different rates of nitrogen fertilizer on fruit yield and quality of two chilli pepper varieties. To this aim a field experiment was carried out and five different nitrogen rates were compared. The authors closely examined the levels of capsaicin, its precursors, competitive substances, as well as the enzyme activities and gene expression related to capsaicin in chilli fruits harvested at three developmental stages and from three different positions on the plant (bottom, middle, and upper). The study is interesting and well structured. However, a careful review of the entire manuscript is recommended to address several inaccuracies. Specifically, there are issues with punctuation, spacing, and various grammatical errors scattered throughout the text. Several sentences are long and unclear. Additionally, a thorough double-check is required for the cited literature in the full paper.

The authors presented a comprehensive and current overview of the topic. However, on page 2, lines 64-69, the sentence should be a note accompanying Figure 1, ideally included in the figure caption rather than within the Introduction section's text. Alternatively, the sentence should be rephrased. In any case, Figure 1 is not cited anywhere in the text. Moreover, the authors should better describe the objective of their study at the end of the “Introdoction” section.

The 'Materials and Methods' section is comprehensive but contains some errors. The sentence at lines 147-149 should be rewritten for clarity. Additionally, the authors could provide a clearer explanation of why they chose the two chilli pepper varieties (such as their diffusion, high yield, high quality, etc.). The sections 2.4.2 and 2.4.3 should be better written: the sentences need a subject, verb, and direct object.

In the “Results” section the authors present the finding observed in their investigation accompanied by graphs. To better understand the graphs the authors should add in the notes the type of post hoc test performed.

This article does not look at tomatoes, eggplant, and cotton, so why did the authors begin the discussion with these crops, which can confuse the reader? In discussion section the authors should not present other results or graphs. So I think that at page 12, lines 360 – 363 the sentence should be moved in the results section, as well as the figure 9. Moreover, considering the environmental issue and the interest in increasingly sustainable agriculture, no comment has been made on this matter by the authors. In my opinion, the authors should highlight these aspects.

The entire manuscript needs a careful check, so below I provide some suggestions and corrections:

Abstract: The first sentence is not grammatical correct, please rewrite.

At line 94, add “and” after number;

at lines 103 and 106 check the punctuation (check the whole article, in several parts there are errors);

at lines 116, 117 and 118, delete fullstop between g and kg and mg and kg;

at line 142 add “plant” after “pepper”;

at lines 181 and 185 check the spacing (check the whole article, in several parts there are errors);

at line 182 replace “anount” with “amount”;

at line 191 correct the word “ammounts”;

at lines 202-203, replace the sentence with “particularly, mineral chenges of lower fruits of “Hongxi” were observed at different N fertilizer concentrations”;

at lines 211- 214, the sentence is not very clear; add ratio after “pacenta/fruit”;

at lines 230-231, explain better the concept;

at line 288, correct “relatede”

at lines 294-295, rewrite the sentence: “Overall, the capsaicin synthetic genes of “Hongxi” fruits were more sensitive to different nitrogen rates than those…”

at lines 317-320, the sentences are unclear, so I suggest the following changes: “There were two reasons for this: first, the nitrogen supply exceeded the pepper requirement, which broken the enzyme system and inhibited fruit growth [32]. The second reason was that excessive nitrogen …..”

at line 374 add “compounds” after phenolic and replace “is” with “are”;

at line 375, move “phenolic” before “precursors” and delete “of”;

at line 380, replace “30 d” with “30th day” and check the whole article and correct the errors;

at line 388, replace “synthesis” with “synthesize”;

at lines 400-402, the sentence is too long, so I suggest: “Li [53] found, in agreement with our results, that the expressions of PAL, AT3, 4CL and HCT initially increased and then decreased during fruit development. Additionally, the expressions of COMT and PAMT continously decreased.”;

at lines 407-409, the sentence is not very clear; moreover, in my opinion the final sentence of the discussion section is overly generic and incomplete, and it appears to be missing references.

At line 412, add the article before “appropriate” and modify the sentence, for example “An appropriate reduction of nitrogen has promoting effects on chilli peppers yield and quality; specifically, a reduction of nitrogen fertilizer by 25% to 50% leads to the maximum values of fruit weight, fruit diameter, fruit length, and placenta weight.”

At line 415, correct “uppper”.

The Authors must pay attention to the citations in the text which must correspond to those listed, I will just give a few examples:

at line 326, the corresponding number after the cited author name is missing;

at lines 331 and 335, the authors should add et al. after the cited author name (check the whole article and correct where it is necessary);

at line 337, “V.Pandhair” is not correct;

Decision: I believe that the paper should be published after major revisions, predominantly in the discussion of the results.

Author Response

Thank you very much for your positive feedback on our manuscript. Undoubtedly, these comments are valuable and very helpful in revising and improving our manuscript. In the attachment, we would like to answer the questions you mentioned and provide a detailed explanation of the changes made to the original manuscript. Please refer to the attachment.

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

Overall, this study provides a valuable contribution to understanding the impact of nitrogen fertilizer on capsaicinoid content and related metabolic processes in chili pepper fruits. The experimental design is robust, and the findings have significant implications for optimizing fertilization strategies to enhance chili pepper spiciness, which is of great interest to both agricultural scientists and farmers. However, there are several weaknesses that need to be addressed before publication. Addressing these issues will significantly strengthen the manuscript and enhance its contribution to the field.

 

Abstract

1.       The objectives are presented generically, without detailing what is specifically expected to be achieved beyond "elucidating and enhancing the impact of nitrogen fertilizer on capsaicin."

2.       Although the methods are mentioned, the description is superficial.

3.       The abstract uses technical terms such as "PAL," "POD," "PPO," "AT3," "4CL," "C4H," "COMT," "PAMT," and "HCT" without explanation. Remember that the abstract is a separate body from the main text, and each acronym in it must be explained.

4.       The results are presented in a very general manner without providing specific quantitative data or statistics to support the conclusions. At least be more specific about placental mass values.

5.       The abstract does not provide sufficient context about the importance of the study or the relevance of capsaicin. This contextualization could appear before the objective.

6.       The unit "hm-2" is not usual, it is preferable to use hectare (ha). Make the substitution throughout the text

 

Introduction

7.       Line 103 - double period at the end of the sentence.

8.       I believe that the introduction does not clearly define the specific problem that the study aims to address. While the importance of capsaicin is mentioned, the direct relationship with the use of nitrogen fertilizers is not sufficiently highlighted.

9.       The introduction mentions the popularity and benefits of chili peppers but does not provide detailed context on the specific challenges of producing high-capsaicin peppers, particularly with respect to fertilizer (nitrogen) use.

10.   The introduction mentions the intention to elucidate the effects of nitrogen fertilizer, but does not specify how this will contribute to the field.

11.   It is unclear why this study is necessary or how it differs from previous research.

12.   There is a lack of smooth transitions between paragraphs, resulting in a fragmented reading experience.

Materials and Methods

13.   On line 149 - 150 - at least include the citation for the Folin-Phenol method and for tannins (Folin-Denis colorimetric method). Specific analytical techniques, instruments, calibration procedures, and standards used should be detailed.

14.   There is no detailed information about the soil type, preparation, or environmental conditions which the experiment was conducted. These factors may significantly affect the results.

15.   The section does not provide a detailed protocol of the number of samples, the part of the plant sampled, and the developmental stages at which sampling occurred.

16.   There is no mention of the statistical methods used to analyze the data. Information about the software, statistical tests, significance levels, and how the data were processed and interpreted is necessary to validate the results.

17.   The procedures for RNA extraction, cDNA synthesis, and qRT-PCR are not detailed enough. Critical information such as primer sequences, reaction conditions, and reference genes used for normalization are missing.

Results and Discussion

18.   In the Results section, the authors fail to provide detailed descriptions of the data, including percentages or magnitudes of differences between treatments, as well as F or p-values. For a rigorous scientific analysis, it is essential to include specific quantitative data and statistical measures to support the findings. For example, stating that there was a "significant increase" without quantifying the increase or providing percentage values is insufficient for rigorous analysis. For example, from rows 208 to 210 it is very important to make it clear how much this increase was in relation to the other treatments.

19.   The discussion lacks a thorough comparison with previous studies. There is no critical analysis of how the results agree or differ from previous research on the effects of nitrogen fertilizer on peppers.

20.   The discussion does not address the limitations of the study. Issues such as environmental variability, measurement precision, and potential experimental errors are not discussed, which compromises the transparency and credibility of the study.

21.   The discussion does not sufficiently explore the practical implications of the results for agriculture or the fertilizer industry. There is no clear link between the results of the study and their practical application in the field.

Conclusions

22.   he conclusions do not sufficiently explore the practical implications of the results. There is no discussion on how the findings can be applied in agricultural practice or in formulating fertilization policies.

 

23.   There are no recommendations for future research. The conclusions should indicate areas that require further investigation to confirm or expand the study's findings.

Author Response

Thank you very much for your positive feedback on our manuscript. Undoubtedly, these comments are valuable and very helpful in revising and improving our manuscript. In the attachment, we would like to answer the questions you mentioned and provide a detailed explanation of the changes made to the original manuscript. Please refer to the attachment.

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

None

Comments for author File: Comments.pdf

Author Response

Dear reviewers,

Thank you very much for your valuable comments on our manuscript. Undoubtedly, these comments have been very helpful in revising and improving our manuscript. We sincerely appreciate the time and effort invested by viewers in evaluating our manuscript.Finally, I wish you all the best.

Reviewer 2 Report

Comments and Suggestions for Authors

The authors have answered at the most comments, but there are still some inaccuracies.

The authors should check the whole manuscript and they should standardize the text by using 'chili' (American English) or 'chilli' (British English).

Check the entire article; there are spacing errors in several parts.

In the “2.5 Data analysis” section, the authors should be modify the sentence, that can be changed in: “Statistical analysis of variance (ANOVA) was performed using IBM SPSS Statistics 26.0 software, relative expression levels of key genes were analyzed using Microsoft Excel. Means were compared using Duncan's post hoc test at p = 0.05 level and plotted using Origin 2021.”  

To enhance the reader's immediate understanding, it is advisable to insert the following sentence under each graph: “Different lowercase letters indicate a significant difference among treatments according to Duncan test (p < 0.05)”.

At line 253-254, the sentence “particularly, there was not significant change of bottom layers fruits of “Hongxi” to nitrogen concentrations.” Is not very clear, so I suggest to write: “whereas, in 'Hongxi' chilli, lower fruit weight was not affect by treatments tested.”

Comments 18: the authors have corrected the wrong sentence: line 388 in the original version is: “it meant there was much more precursors to synthesis capsai-…..” and not the sentence that was modified by the authors (“there is competition between the synthesis of capsaicinoids and tannins,”, that is corrected in this way). So in the sentence “it meant there was much more precursors to synthesis capsai-…..” “synthesis” should be replaced by “synthetize”.

Response 19: In my opinion the sentence is too long and not correct. So I suggest to to modify as follows: “Li [53] found that the expressions of PAL, AT3, 4CL and HCT initially increased and decreased during fruit development, in agreement with our results. Additionally, the expressions of COMT and PAMT continously decreased.”

Finally, only the last names of the cited authors should be indicated in the text, so it is necessary to carefully check the entire article.

Author Response

Dear reviewers,

Thank you very much for your valuable comments on our manuscript. Undoubtedly, these comments have been very helpful in revising and improving our manuscript. In the following, we would like to answer the questions you have mentioned and give details of the changes made to the manuscript.

Author Response File: Author Response.pdf