Evaluation of the Antifungal Activity of Polysubstituted Cyclic 1,2-Diketones against Colletotrichum gloeosporioides

Round 1

Reviewer 1 Report

The manuscript is well written and easy to follow. The development and testing of new non-pollution fungicide will help to save the nature in the future.

But still I have some questions/comments about the manuscript.

Fig 1 - Is inhibition of mycelia growth80%  sufficient to suppress the damage caused by this pathogen

Fig 1 and Fig 2 - the authors have analysed the anti fungal activity of diketones. I was wondering what will happen when the diketone(s) are regarded and their concentration will go down. Are the pathogens able to start growing again or are the damages lethal.

Fig 3 a, b - it is a little bit difficult to follow which spot corresponds to what mixture; when I looked on parts d and e I think that I understood also the a and b section. 

Author Response

We thank you for your helpful comments and suggestions for improving the manuscript. I appreciate the reviewer’s suggestions. The answers to the question are as follows.

1 Question: Fig 1- Is inhibition of mycelia growth 80% sufficient to suppress the damage caused by this pathogen?

Response: Thank you for this suggestion. In our study, antifungal compounds of polysubstituted cyclic 1,2-diketones FPL001 significantly inhibited the mycelia growth of C. globosporioides in a dose-dependent. When the concentration reached 300 µg/mL, the inhibition rate of FPL001 reached 61.58%. Thus, we suggest that a higher concentration of FPL001 may exhibit more severely inhibition for mycelial growth of C. globosporiodies.

In addition, condium and appressoria play important roles in the infected cycle of C. gloeosporioides. In the Figure 2, FPL001 effectively inhibited conidia germination and appressorium development of phytopathogen SMCG1#C in the low concentration.

Collectively, these results indicated that antifungal compounds of polysubstituted cyclic 1,2-diketones FPL001 is an advanced fungicide.

 

2 Question: Fig 1 and Fig 2 - the authors have analysed the antifungal activity of diketones. I wondered what will happen when the diketone(s) are regarded and their concentration decreases. Are the pathogens able to start growing again or are the damages lethal?

Response: Thank you for your question. In the Figure 1 and Firgure 2, our data showed that FPL001 significantly inhibited mycelia growth, conidia germination and appressorium development of C. gloeosporioides in a dose-dependent. In the low concentration of 10 µg/mL, antifungal compounds FPL001 dramatically suppressed conidial germination and appressorium development of C. gloeosporioides, while the mycelia growth only exhibited delayed, that was not completely stopped growth. According to this database, we speculate that a low concentration of compounds FPL001 suppressed the development of phytopathogen rather than damages lethal.

3 Question: Fig 3 a, b - it is a little bit difficult to follow which spot corresponds to what mixture; when I looked on parts d and e I think that I understood also the a and b section.

Response: Thank you for your comments. I changed this Figure 3. The blurred markings have been corrected. We have revised the figure legend in detail in lines 231 -237.

Author Response File: Author Response.docx

Reviewer 2 Report

The manuscript entitled " Evaluation of the antifungal activity of polysubstituted cyclic 2 1,2-diketones against Colletotrichum gloeosporioides" had as the objective to characterize the effect of FPL001 on the agronomically important pathogen, plants, and insect larvae to prove the prospects of using it as a biofungicide. The biological activity described presents interesting information about this preparation. Below I have listed some questions that otherwise should improve the final quality of the manuscript. My consideration is acceptance after minor revision.

In subsections 3.6 and 3.7, the authors would like to quantify the « not significant» effect of FPL001.

In the Discussion section, could the authors compare the activity of FPL001 against C. gloeosporioides with the activity of other biofungicides.

Author Response

Reviewer # 2

1 Question: In subsections 3.6 and 3.7, the authors would like to quantify the « not significant» effect of FPL001.

Response: Thank you for your comments. In subsections 3.6 and 3.7, to investigate the potential damages of FPL001, we detected the ecotoxicity of FPL001 for alfalfa seeds and silkworm larvae. These results performed that high concentrations of FPL001 were non-toxic to alfalfa seeds and silkworm larvae. Combining whole results, we suggest that compounds FPL001 is friendly to environment, and it is worth developing product as a fungicide.

2 Question: In the Discussion section, could the authors compare the activity of FPL001 against C. gloeosporioides with the activity of other biofungicides?

Response: Thank you for your valuable suggestions! We have added words to the discussion in lines 331-335 in the revised manuscript.

Author Response File: Author Response.docx