Adventitious Root Culture—An Alternative Strategy for Secondary Metabolite Production: A Review

Round 1

Reviewer 1 Report

The review article is well written and thoroughly described and it can find interest among the researchers in this field. However, there are some important corrections needed which must be incorporated before its possible acceptance.

The title is not expressive corresponding to the objectives and arguments developed in the MS. It should be revised in an elaborative manner.

Moreover, the language used in this manuscript needs some attentions as well. There are some major/minor grammar and spelling and sentences errors throughout the manuscript that should be edited by some native English-speaking expert. Few examples of language correction are given below from abstract section

Introduction: I think lines 34-39 of the section are irrelevant, and it should be removed. This section is too lengthy and there are irrelevant statements as well, which makes it little speculative. Please refer to the following literature to further improve this section.

Halder, M., Roychowdhury, D., & Jha, S. (2018). A critical review on biotechnological interventions for production and yield enhancement of secondary metabolites in hairy root cultures. Hairy roots, 21-44.

Paolis, A.D.; Frugis, G.; Giannino, D.; Iannelli, M.A.; Mele, G.; Rugini, E.; Silvestri, C.; Sparvoli, F.; Testone, G.; Mauro, M.L.; Nicolodi, C.; Caretto, S. Plant Cellular and Molecular Biotechnology: Following Mariotti’s Steps. Plants 2019, 8, 18. https://doi.org/10.3390/plants8010018

Gantait, S., & Mukherjee, E. (2021). Hairy root culture technology: applications, constraints, and prospect. Applied Microbiology and Biotechnology, 105(1), 35-53.

Zhou, M. L., Zhu, X. M., Shao, J. R., Tang, Y. X., & Wu, Y. M. (2011). Production and metabolic engineering of bioactive substances in plant hairy root culture. Applied microbiology and biotechnology, 90(4), 1229-1239.

Roy, A. (2021). Hairy root culture an alternative for bioactive compound production from medicinal plants. Current pharmaceutical biotechnology, 22(1), 136-149.

Lines 148-164: I think this paragraph is more suitable for the heading 2.2. It created sense of repetition of the same arguments.

Heading 2.4: effect of NaCl: why only the salt stress is mentioned here? While there are some other abiotic factors as well that correspond to the adventurous roots’ formation. I think this section should be mentioned as abiotic factors by discussing some other factors as well. The authors can also discuss the role of different biotic and abiotic elicitors as well in this section.

There is a need to add a list of medicinal plants in which different elicitation strategies have been applied to induce adventitious roots, in a tabular form supported with lates bibliography.

Authors should also elaborate the difference between hairy roots and adventitious roots in a separate heading and compare their significance for current and future studies.

The role of bioreactors is very important, and it is evolving day by day. So, this section should also be little more elaborative in terms of describing different types of bioreactors, specifically significance of membrane bioreactors to understand the aerobic and anaerobic conditions of root cultures in liquid medium. Possibly the authors can add another table describing the types and roles of different bioreactors in elicitation of secondary metabolites from medicinal plants.

I think it would be more effective if the authors can add another flow diagram elaborating the adventitious root production strategy with the help of bioreactors.

The culture medium also plays a vital role for root culture technology; therefore, authors should mention a separate section discussing about the role of media properties and culture conditions.

Authors have mentioned the advantages of adventitious root cultures but, if possible, they should also mention the challenges to use root culture as well.

To sum up, the MS can find interest to the specialists in this field. However, above-mentioned major concerns should be addressed.

Good Luck!

Author Response

The review article is well written and thoroughly described and it can find interest among the researchers in this field. However, there are some important corrections needed which must be incorporated before its possible acceptance.

First of all, we would like to acknowledge the reviewer for taking time to read the manuscript carefully and critically. We have revised the suggested items.

R1: The title is not expressive corresponding to the objectives and arguments developed in the MS. It should be revised in an elaborative manner.

A1: The title has been improved as suggested by the reviewer

 

R2: Moreover, the language used in this manuscript needs some attentions as well. There are some major/minor grammar and spelling and sentences errors throughout the manuscript that should be edited by some native English-speaking expert. Few examples of language correction are given below from abstract section

A2: Language has been improved

 

R3: Introduction: I think lines 34-39 of the section are irrelevant, and it should be removed. This section is too lengthy and there are irrelevant statements as well, which makes it little speculative. Please refer to the following literature to further improve this section.

A3: This part has been removed as recommended. Moreover, the suggested references are about hairy root culture, however our study is mainly focussed on adventitious root culture.

Halder, M., Roychowdhury, D., & Jha, S. (2018). A critical review on biotechnological interventions for production and yield enhancement of secondary metabolites in hairy root cultures. Hairy roots, 21-44.

Paolis, A.D.; Frugis, G.; Giannino, D.; Iannelli, M.A.; Mele, G.; Rugini, E.; Silvestri, C.; Sparvoli, F.; Testone, G.; Mauro, M.L.; Nicolodi, C.; Caretto, S. Plant Cellular and Molecular Biotechnology: Following Mariotti’s Steps. Plants 2019, 8, 18. https://doi.org/10.3390/plants8010018

Gantait, S., & Mukherjee, E. (2021). Hairy root culture technology: applications, constraints, and prospect. Applied Microbiology and Biotechnology, 105(1), 35-53.

Zhou, M. L., Zhu, X. M., Shao, J. R., Tang, Y. X., & Wu, Y. M. (2011). Production and metabolic engineering of bioactive substances in plant hairy root culture. Applied microbiology and biotechnology, 90(4), 1229-1239.

Roy, A. (2021). Hairy root culture an alternative for bioactive compound production from medicinal plants. Current pharmaceutical biotechnology, 22(1), 136-149.

 

R4: Lines 148-164: I think this paragraph is more suitable for the heading 2.2. It created sense of repetition of the same arguments.

A4: This section has been shifted under heading 2.2.

 

R5: Heading 2.4: effect of NaCl: why only the salt stress is mentioned here? While there are some other abiotic factors as well that correspond to the adventurous roots’ formation. I think this section should be mentioned as abiotic factors by discussing some other factors as well. The authors can also discuss the role of different biotic and abiotic elicitors as well in this section.

A5: It has been shifted under a common heading of abiotic elicitors.

 

R6: There is a need to add a list of medicinal plants in which different elicitation strategies have been applied to induce adventitious roots, in a tabular form supported with lates bibliography.

A6: It has been done, as requested.

 

R7: Authors should also elaborate the difference between hairy roots and adventitious roots in a separate heading and compare their significance for current and future studies.

A7: It has been discussed under introduction section.

 

R8: The role of bioreactors is very important, and it is evolving day by day. So, this section should also be little more elaborative in terms of describing different types of bioreactors, specifically significance of membrane bioreactors to understand the aerobic and anaerobic conditions of root cultures in liquid medium. Possibly the authors can add another table describing the types and roles of different bioreactors in elicitation of secondary metabolites from medicinal plants.

A8: It has been added now.

 

R9: I think it would be more effective if the authors can add another flow diagram elaborating the adventitious root production strategy with the help of bioreactors.

A9: The flow diagram has been added.

 

R10: The culture medium also plays a vital role for root culture technology; therefore, authors should mention a separate section discussing about the role of media properties and culture conditions.

A10: This part has been added as requested.

 

R11: Authors have mentioned the advantages of adventitious root cultures but, if possible, they should also mention the challenges to use root culture as well.

A11: It has been added accordingly.

 

To sum up, the MS can find interest to the specialists in this field. However, above-mentioned major concerns should be addressed.

Thanks again for the constructive comments, we do hope all have been addressed.

Good Luck!

Reviewer 2 Report

The review article is a useful to guide for the future researchers, I noticed that there are several outdated references are mentioned, I would suggest covering updated techniques and references

The abstract needs to improve with the main article, some important points need to be reflected in the abstract.

The introduction is well written, however, needs to improve the last para with past and future prospects, and recommendations.

100-110 There are many commercial hormones are used in plant tissue culture with great potential in research, its more useful to add in this review for better comparison  

I also suggest improving the introduction with the clear objectives of the review and why do you need to introduce this review

135-137 “Adventitious root can be formed via direct organogenesis from cambium cells and indirect organogenesis from callus tissues. These cultures show high rates of proliferation with active metabolism and enhanced rate of growth” these lines are not inconsistent with the reference, therefore rewrite or modify

 “2.2. Effect of auxins on adventitious root cultures” this should be root formation or initiation

Table 1. role of PGRs concentration should be mentioned with the uniform units

 Figure 2 legends do not well describe the figure, it should be self-explanatory

 2.6 biotic elicitors and bioreactors enlist in table

In the conclusion, part mention the way forward

 

Author Response

The review article is a useful to guide for the future researchers, I noticed that there are several outdated references are mentioned, I would suggest covering updated techniques and references.

Thank you for the precise revision and taking the time to critical revision of our manuscript, we have amended the requested items accordingly. We have updated the references as suggested.

R1: The abstract needs to improve with the main article, some important points need to be reflected in the abstract.

A1: This section has been improved now.

 

R2: The introduction is well written, however, needs to improve the last para with past and future prospects, and recommendations.

A2: It has been done, as requested.

 

R3: 100-110 There are many commercial hormones are used in plant tissue culture with great potential in research, its more useful to add in this review for better comparison  

A3: Thank you for the suggestion, we have performed as requested, considering that this study focuses on the effects of auxins.

 

R4: I also suggest improving the introduction with the clear objectives of the review and why do you need to introduce this review

A4: It has been done accordingly.

 

R5: 135-137 “Adventitious root can be formed via direct organogenesis from cambium cells and indirect organogenesis from callus tissues. These cultures show high rates of proliferation with active metabolism and enhanced rate of growth” these lines are not inconsistent with the reference, therefore rewrite or modify

A5: It has been done accordingly.

 

R6: “2.2. Effect of auxins on adventitious root cultures” this should be root formation or initiation

A6: As requested it has been corrected.

 

R7: Table 1. role of PGRs concentration should be mentioned with the uniform units

A7: Thank you for the suggestion, however we have mentioned the values in accordance with the literature, thus we will be grateful if we can keep in this form.

 

R8: Figure 2 legends do not well describe the figure, it should be self-explanatory

A8: The legend has been modified now.

 

R9: 2.6 biotic elicitors and bioreactors enlist in table

A9: Attached the effect of biotic and abiotic elicitors in tabular form

 

R10: In the conclusion, part mention the way forward

A10: The conclusion has been revised

Round 2

Reviewer 1 Report

Dear Authors, 

now I found your manuscript suitable to be published. 

My greetings!