Germination and Culturability after UV Irradiation of Metarhizium anisopliae Native from Soils of Tropical Cattle Farms

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

This short report has tested 8 strains of Metarhizium anisopliae and presented that 6 of them are UV-tolerant M. anisopliae strains. This manuscript provided the information that in the natural environment, there still have M. anisopliae stains could against UV. I have only one comment”

In the abstract: “The finding of UV-tolerant M. anisopliae strains could improve the effectiveness of EF in field conditions.” In my opinion, the data provided by the authors could not prove the “improvement of UV-tolerant”  Therefore, please rewrite this part.

Author Response

This short report has tested 8 strains of Metarhizium anisopliae and presented that 6 of them are UV-tolerant M. anisopliae strains. This manuscript provided the information that in the natural environment, there still have M. anisopliae stains could against UV. I have only one comment”

In the abstract: “The finding of UV-tolerant M. anisopliae strains could improve the effectiveness of EF in field conditions.” In my opinion, the data provided by the authors could not prove the “improvement of UV-tolerant”  Therefore, please rewrite this part.

R: Thanks for the comment. We agree with the reviewer, the sentence was possibly very ambitious. We have changed the sentence to a more achievable idea under the conditions of the experiment.

Reviewer 2 Report

Comments and Suggestions for Authors

Entomopathogenic fungi is a group of microorganisms widely applied against arthropod pests in crop and cattle protection. Numerous studies are aimed to disclose and improve the efficiency of Metarhizium spp. against bovine ticks. These fungi possess contact activity and need to be applied on the surface of protected animals, thus exposing the microbial agents to direct sunlight (if applied during the daytime). As it contains a considerable amount of ultraviolet rays in its spectrum, the sunlight poses threat to the fungal cells decreasing their viability. The search for and selection of the UV-resistant strains of a partical fungus is therefore of great practical importance. Thus, the paper is in the mainstream of modern research in the field of biological control and fairly suits the journal scope. Substantiation of the study is properly covered in the Introduction. The paper style, structure and size conform with the journal requirements. Referenced literature is up-to-date; the study design is appropriate, the obtained data are rigorously discussed. Minor critical comments are as followed:

1)     The tables are informative but better presentation of the data, graphics are welcome, while the detailed numbers can be given as supplementary material.

2)     The Discussion chapter starts with ”The hypothesis posited in this investigation suggested that exposure of EF strains to UV facilitate the differentiation and selection of strains”. However, this hypothesis is not new and numerous studies (some of which are referenced) have been dedicated to this problem ( if we concern EF in general). These studies are performed over decades and it is better to indicate that this well-known phenomenon is studied herein for particular case of tick-pathogenic Metarhizium.

 

Comments on the Quality of English Language

Very few mistakes of grammar & style were found:

 

L53: in field conditions = under field conditions

L70: molecularly identified = identified using molecular tools

L85: each M. anisopliae strains – “each” implies singular

L91-95: rearrange the list of variants

L92: smaller than 400 nm = shorter than 400 nm

L131: the percentages – doubt plural needed here

L134: While – inappropriate start of the sentence

L148: a strain – which one?

L163: irradiations – doubt plural needed here

Ibidem: Five of them strains = Five of them

L180: to two groups = to the two groups

L209: inappropriate usage of dot

 

 

Author Response

Entomopathogenic fungi is a group of microorganisms widely applied against arthropod pests in crop and cattle protection. Numerous studies are aimed to disclose and improve the efficiency of Metarhizium spp. against bovine ticks. These fungi possess contact activity and need to be applied on the surface of protected animals, thus exposing the microbial agents to direct sunlight (if applied during the daytime). As it contains a considerable amount of ultraviolet rays in its spectrum, the sunlight poses threat to the fungal cells decreasing their viability. The search for and selection of the UV-resistant strains of a partical fungus is therefore of great practical importance. Thus, the paper is in the mainstream of modern research in the field of biological control and fairly suits the journal scope. Substantiation of the study is properly covered in the Introduction. The paper style, structure and size conform with the journal requirements. Referenced literature is up-to-date; the study design is appropriate, the obtained data are rigorously discussed. Minor critical comments are as followed:

R: Thank you very much for the kind and constructive comments. We have attended all in order to improve our work.

1)     The tables are informative but better presentation of the data, graphics are welcome, while the detailed numbers can be given as supplementary material.

R: Tables have been replaced by Figures in the manuscript.

2)     The Discussion chapter starts with ”The hypothesis posited in this investigation suggested that exposure of EF strains to UV facilitate the differentiation and selection of strains”. However, this hypothesis is not new and numerous studies (some of which are referenced) have been dedicated to this problem ( if we concern EF in general). These studies are performed over decades and it is better to indicate that this well-known phenomenon is studied herein for particular case of tick-pathogenic Metarhizium.

R: The paragraph has been re-written, considering the reviewer observation. Lines 163-166.

Comments on the Quality of English Language

Very few mistakes of grammar & style were found:

R:We thank you for the time to identify and advice over grammar mistakes. All of then had been adjusted.

L53: in field conditions = under field conditions

R:The change was done. L54.

L70: molecularly identified = identified using molecular tools

R:The change was done.  L71.

L85: each M. anisopliae strains – “each” implies singular

The text was adjusted. L86.

L91-95: rearrange the list of variants

The text was re-written. L92-96.

L92: smaller than 400 nm = shorter than 400 nm

R:The change was done. L93.

L131: the percentages – doubt plural needed here

The text was corrected . L132.

L134: While – inappropriate start of the sentence

The text was corrected. L135.

L148: a strain – which one?

The information has been added.  L151

L163: irradiations – doubt plural needed here

L167. Text was corrected

Ibidem: Five of them strains = Five of them

Text was corrected. L169.

L180: to two groups = to the two groups

Line 109. Corrected.

L209: inappropriate usage of dot

Text was corrected L213-216.

Reviewer 3 Report

Comments and Suggestions for Authors

The manuscript, "Germination and culturability after UV irradiation of Metarhizium anisopliae native from soils of tropical cattle farms' provides very brief data on the effect of UV ray exposure on the growth of fungi. I think that  this data is not enough to support the practical importance of the study.

1. The introduction provides a very brief overview of the importance of this EF on the control of ticks. But the experimental setup nowhere shows that UV exposure to EF affects its impact on ticks. Is this related to each other on any way or other?

2. The quantum of work is very little to support the fact that this work has some practical importance.

3. Although the materials and methods are depicted, but some more experiments need to be conducted to add importance to the study.

4. The conclusion talks about more in -vivo and in-vitro studies to assess other factors or characteristics influencing the effectiveness of M. anisopliae as an alternative tick control method. However, authors have not conducted any such experiment in this paper. 

I think more work needs to be done to improve the scientific soundness of the manuscript.

 

Author Response

The manuscript, "Germination and culturability after UV irradiation of Metarhizium anisopliae native from soils of tropical cattle farms' provides very brief data on the effect of UV ray exposure on the growth of fungi. I think that this data is not enough to support the practical importance of the study.

We deeply thank for the reviewer’s comments. As well, we offer as reply to those comments our perspective and probably a wider background of our study. We have also added lines to our abstract, conclusions and discussion considering your concerns.

This study aimed to evaluate eight EF strains isolated from livestock habitats in tropical areas, where high temperatures and humidity could stimulate some evolutionary adaptation to extreme temperatures and collateral exposures, such as UV rays. The EF strains of the study were selected from a mycological collection that is made up of at least 59 strains, on which evaluations of their effect against R. microplus ticks in their different stages were carried out. These results are part of an integrated project and knowledge of their adaptation to the environment where their use will highly very important.

The results may seem brief, nevertheless they are of high novelty and interest to the scientific community that studies biological pest control. The results are presented as a “brief report”, nevertheless they form part of a complete investigation and are, without a doubt, original advances in knowledge and understanding of the use of EF in tropical problems.

1. The introduction provides a very brief overview of the importance of this EF on the control of ticks. But the experimental setup nowhere shows that UV exposure to EF affects its impact on ticks. Is this related to each other on any way or other?

The relationship between the ability of EF to tolerate UV exposure and its ability to kill ticks is very close and can be approached from different aspects. The most important is that UV rays have a high germicidal effect on fungal cells and these cells are potentially applied directly to the cattle or sprayed on pastures to control ticks. A situation that exposes the fungi to UV rays. For this reason, strains that have the ability to tolerate this exposure could have better mortality effects against ticks.

2. The quantum of work is very little to support the fact that this work has some practical importance.

As mentioned, this study is part of a very extensive integrated project where fungal isolations and tickcide evaluations were first carried out at laboratory level. The next step is precisely to determine its response capacity to abiotic factors (temperature, exposure to UV rays, humidity, etc.) and the determination of lethal concentrations to apply the best effective doses at the field level (https://doi.org/10.1645/23-27 ; https://doi.org/10.3958/059.047.0203 ). This field evaluation is the next step in this complete integrated investigation.

3. Although the materials and methods are depicted, but some more experiments need to be conducted to add importance to the study.

The experimental approach that could be carried out and added to this study with a logical relationship is the evaluation of EF strains at field level. However, that evaluation could be itself, very extensive and complicated to evaluate the 8 strains. This if considering that to evaluate 30 animals are needed per strain at least in the experiment (treatment group, positive control group and negative control group).

4. The conclusion talks about more in -vivo and in-vitro studies to assess other factors or characteristics influencing the effectiveness of M. anisopliae as an alternative tick control method. However, authors have not conducted any such experiment in this paper. 

To obtain EF strains effective against ticks under real natural conditions, a large number of evaluations need to be performed. In an integrated approach, a large amount of research has been carried out on these EF strains that are published in other manuscripts. However, we consider important to inform, motivate and invite other researchers to carry out more studies in this regard, either with these fungi strains or with others.

I think more work needs to be done to improve the scientific soundness of the manuscript.

Round 2

Reviewer 3 Report

Comments and Suggestions for Authors

I am satisfied with the changes that authors have made in the manuscript. They have tried to answer all the questions precisely.

Author Response

Once again, we the authors thank you for the editor and reviewers’ consideration to publish our report.