Management of Eleusine indica (L.) Gaertn Resistance to Glyphosate Herbicide in Indonesia

Round 1

Reviewer 1 Report

This manuscript presents some good and sound data about the putative mechanism of resistance to glyphosate of five Indonesian ELEIN populations. However, and although the experimental design, Introduction and the M&M used are fair, it cannot be published as it is.

The manuscript lacks of a real discussion, with authors failing in connecting their findings to previous studies and/or developing some hypothesis about what results are presenting to us.

Therefore, I consider this manuscript as “reconsider after major revision”. With a proper and much more elaborated discussion, this study would be ok for publication, since the subject (herbicide resistance in weeds) is interesting and both the methods used and the data obtained are consistent.

A line by line comment can be found below:

Line 37 and whole text: The manuscript presents too many cites for a study containing just a dose-response assay plus a gene sequencing assay. You do not need cites 3, 4, and 5 just to say that weed management is important. Try not to be redundant. Instead of 50 references, 30-35 would be fine.

Line 39: Some background about ELEIN genetics would be highly desirable. Is it a self- or cross-pollinated species, for example?

Line 50: Again, redundant. Heap is enough

Lines 54-56: This explanation is too simple, considering the data you are about to present to the reader. You must include here both TSR and NTSR, the concept of cross and multiple resistance, and the possibility of biotypes showing more than one mechanism of resistance. This is especially important in glyphosate resistance since the presence of one mechanism of resistance (target site mutation in this case) does not imply the absence of other mechanisms involved.

Lines 73-74: Resistance to glyphosate has become a huge problem in agriculture. Authors should state the magnitude of the problem worldwide and not only locally. How many species involving how many biotypes? How many countries? Use Heap.

Lines 84-88: There are not clear objectives stated here. What is the purpose of the study? What are the findings we are trying to find? Which studies are we going to carry out to get the answers? The paragraph lacks a sentence stating the real problem faced by the study.

Line 98 (table 5): What is the story of these five populations? Which and how many herbicides were used? How many years? Some information about this can be found at the discussion section, but placed so far in the text prevents the readers from assuming their own conclusions

Lines 145-152: There is no LSD test anywhere Table 2. How can authors affirm differences are significant or not?

Lines 165-166: “…the E. indica-resistant biotype did not experience a 100% growth reduction…” Which one(s)?

Lines 171-176 (Figure 2): Figure 2 is redundant and does not add any valuable information to table 2 and figure 1. Delete.

Lines 177: “The resistant biotype of E. indica experienced…” Again, which one(s)?

Lines 193-203: Move this paragraph to introduction.

Lines 204-214: This paragraph does not discuss your data, it is just some facts about herbicide resistance. Delete.

Lines 215-234: A brief version of this should be moved from here to introduction. You should compare here your ELEIN data and results with other ELEIN or weed DATA AND RESULTS. That includes other glyphosate-resistant ELEIN populations, other double 102/106 weed mutants, and other glyphosate-paraquat cross resistant weed biotypes. Do they show the same resistance ratios? Do they present more than one mechanism of resistance? Does a double point mutation render more glyphosate resistance than the usual (Pro-ser 106) single one?

Lines 235 to 244: Move (in a brief version) to introduction

Lines 245-252: Here you are citing other glyphosate –resistant weed biotypes, but not comparing. They present (or not) the same mutations observed in the Indonesian biotypes but, what about their response to glyphosate? If you are showing GR50 values in this study, use them.

Lines 266-284: All these facts are not relevant, and they are somehow expressed in the previous paragraph. Delete.

 

Author Response

Dear Reviewer the editor and Reviewer ,

Thank you for your comments, and I have revised the manuscript 

Author Response File: Author Response.docx

Reviewer 2 Report

In the agronomy-2450735 manuscript, Kurniadie et al. confirmed the occurrence of glyphosate resistance in E. indica in Indonesian oil palm plantations, which, based on molecular biology results, is governed by the combination of TIPS mutations. In addition, some populations showed multiple resistance to glufosinate and paraquat. On the other hand, some herbicides, such as propaquizafop, ametryn, and sulfentrazone, are still efficient in controlling these resistant populations of E. indica. The experimental work is simple, but correct, however, throughout the text there are many typos and inconsistencies in the wording of the text. The description of results could be improved, but in its current form it is sufficient. However, the topic with the most weaknesses is discussion, since it is practically non-existent. Aspects that need to be corrected/complemented are listed below so that the manuscript can be considered for publication.

L55: Glyphosate resistance is not conferred by mutations alone. Report that other TSR and NTSR mechanisms have been described conferring resistance to this herbicide.

 L80-81: provide a proper reference to support this claim

 L115: both the volume of application and the pressure used are very high. None of these parameters is appropriate for herbicide applications. Explain on the basis of which these parameters were defined.

 L156: Figure 1 could be assembled in a way that makes better use of space

 L159: the authors classify the resistance level of the GR50 values using a scale that was not mentioned before. Furthermore, there is no discussion related to that classification, that is, this column does not make sense in the manuscript. It is unnecessary text

 L186-188: It is striking that all the resistant populations present the combination of TIPS mutations, but the levels of resistance are divergent. In the case of TSR-driven glyphosate resistance, the type of mutation governs the level of resistance. You should explain these differences in your discussion.

 L192-284: Discussion of your own results is practically non-existent, it's just a broad literature review. This should be fully rewritten with a focus on explaining the dose response results, not only for glyphosate, but paraquat and glufosinate as well. The impact of the 106 mutation on the interaction of the herbicide molecule and the EPSPS, the impact of the 102 mutation, and how the simultaneous occurrence of both mutations impacts the E. indica management. Finally, discuss the implications of multiple resistance and the possibility of still having some herbicides for the management of E. indica.

 L194-203: All this information is disconnected from the work described in the methodology and the results described. You mention that you did interviews and describe stories from some producers. However, you did not mention anything about it before. These lines must be eliminated or it must be adequately described when the surveys were carried out, how many producers were interviewed, what were the topics covered in the surveys, etc.

 

L204-214: DELETE- All this information is just a literature review, not a discussion of your results. In addition, some of these information were already mentioned in the introduction.

 L215-232: Review of very extensive literature on resistance to hebricides in E. indica. You should focus on explaining your own results, not on mentioning the results of other research. Do it punctually so that it serves to support/contrast your results

 L237-252: Similar to the previous topic. The review of mutations conferring resistance to glyphosate is unnecessarily extensive, and little or nothing is used to explain your results. Scientifically explain how mutation(s) described in another species(s) support your results. Integrate this information in a single paragraph in a brief way. Check comment for L186-188.

L266-284: these two discussion paragraphs have little bearing on your results, since you did not evaluate herbicide mixtures. you can mention it, but very briefly, and do not do a literature review.

 Other specific comments are highlighted in the attached document

 

 

 

 

Comments for author File: Comments.pdf

grammar should be checked by a professional

Author Response

Dear Reviewer 2,

Thank you for your comments and I have revised the manuscript.

Author Response File: Author Response.docx

Round 2

Reviewer 1 Report

After the revision, the manuscript looks much more concise and consistent, containing valuable information about glyphosate resistance in Indoniseian ELEIN biotypes. Therefore this reviewer considers it ready for publication

Just some additions and mistypings:

Line 54: Change "Site Resistance Site" to "Target Site Resistance"

LIne 55: Change "and" to "and/or"

Line 61: Change "...weed resistance..." to "...TSR..." or "...target site resistance..." Weed are resistant, but there is not such a "resistance to weeds"

Line 63: Change "The herbicide loses..." to "In TSR cases, the herbicide loses..."

Author Response

Thanks so much for your work. We have revised those terms.

Reviewer 2 Report

Kurniadie considerably improved their manuscript, however, various inconsistencies can still be found throughout the manuscript, be they typographical errors, misstatements, as well as inappropriate use of abbreviations to mention the mechanisms of action of herbicides. Authors must carefully correct this type of inconsistency throughout the manuscript. In the attached document, I have highlighted the most obvious ones.

Comments for author File: Comments.pdf

minor typos

Author Response

please see the attachment, thanks

Author Response File: Author Response.pdf