Review Reports - Phytohormonal Regulation of Plant Responses to Major Abiotic Stresses: From Signaling Pathways to Hormonal Crosstalk

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

Plants are constantly exposed to too many different types of diverse abiotic stresses, including drought, salinity, and high temperatures, which severely inhibit plant growth, development, and crop productivity. Phytohormones play key roles in regulating adaptive stress responses. In this review paper, the authors summarized the latest progress of Key hormones, including abscisic acid (ABA), salicylic acid (SA), jasmonates (JAs), gibberellins (GAs), auxin (IAA), ethylene (ET), melatonin, and strigolactones (SLs) in regulating stress tolerance by controlling stomatal behavior, root architecture, antioxidant systems, osmolyte accumulation, and stress-responsive gene expression and crosstalk network of these hormones In general, this manuscript was well written and summarized the progress of these key plant hormore in regulating plants response to abiotic stress. I have the following comments:

Comments:

The first letter for each key word should be capital;
For all the Figures, if you cited some from other authors’ result, you should cited the key references;
One section is missing, the authors should one section, future perspective and challenges as the end of review paper;
The format of references are not consistent and provide doi number with https://; some without https, which was not consistent, the authors should use the same format..

Additional comments:

Key hormones, including abscisic acid (ABA), salicylic acid (SA), jasmonates (JAs), gibberellins (GAs), auxin (IAA), ethylene (ET), melatonin, and strigolactones (SLs), regulate stress tolerance by controlling stomatal behavior, root architecture, antioxidant systems, osmolyte accumulation, and stress-responsive gene expression.• Do you consider the topic original or relevant to the field? Does it address a specific gap in the field? Please also explain why this is/ is not the case.

Author Response

Reviewers' report and authors' answers for the manuscript submitted to Metabolites, MDPI, Special issue.

1^st reviewer

Comments and Suggestions for Authors

Plants are constantly exposed to too many different types of diverse abiotic stresses, including drought, salinity, and high temperatures, which severely inhibit plant growth development, and crop productivity. Phytohormones play key roles in regulating adaptive stress responses. In this review paper, the authors summarized the latest progress of Key hormones, including abscisic acid (ABA), salicylic acid (SA), jasmonates (JAs), gibberellins (GAs), auxin (lAA), ethylene (ET), melatonin, and strigolactones (SLs) in regulating stress tolerance by controlling stomatal behavior, root architecture, antioxidant systems, osmolyte accumulation, and stress-responsive gene expression and crosstalk network of these hormones In general, this manuscript was well written and summarized the progress of these key plant hormone in regulating plants response to abiotic stress. I have the following comments:

We sincerely appreciate your time and expertise in reviewing our work. We have carefully considered your suggestions and revised the manuscript accordingly.

All changes in the revised manuscript are highlighted in yellow.

Below, we also provide a point-by-point response explaining how we have addressed each reviewer's comment.

Authors,

25.5.2026

Comments:

1.The first letter for each key word should be capital;

Revised as suggested. Changes are highlighted in yellow in lines 26 and 27.

For all the Figures, if you cited some from other authors' result, you should cited the key

references;

The key references for the figures have been added as suggested and highlighted in yellow.
Figure 1: page 4
Figure 2: page 5
Figure 3: page 6
Figure 4: page 8

Figure 5: page 16

One section is missing, the authors should one section, future perspective and challenges as the end of review paper;

This section has been added to the end of the review (page 17) and highlighted in yellow.

The format of references are not consistent and provide doi number with https://; some without https, which was not consistent, the authors should use the same format.

All DOI links were revised and unified to the “http” format.

Additional comments:

Key hormones, including abscisic acid (ABA), salicylic acid (SA), jasmonates (JAs), gibberellins (GAs), auxin (lAA), ethylene (ET), melatonin, and strigolactones (SLs), regulate stress tolerance by controlling stomatal behavior, root architecture, antioxidant systems, osmolyte accumulation, and stress-responsive gene expression.· Do you consider the topic original or relevant to the field? Does it address a specific gap in the field? Please also explain why this is/ is not the case.

We thank the reviewer for this comment. The topic is relevant and timely in the field of plant abiotic stress biology. Phytohormones such as ABA, SA, JAs, GAs, IAA, ET, melatonin, and SLs are well-known regulators of plant growth and stress responses and are now understood as interconnected signaling components rather than isolated pathways.

The originality of this review lies in its integrated discussion of hormonal crosstalk across abiotic stresses. While the review considers drought, salinity, heat, and cold stress separately, it focuses in particular on how these hormones interact and converge through shared signaling components, including ROS, calcium signaling, MAPKs/CDPKs, and transcription factors. This approach helps address a gap by organizing recent findings into a coherent framework for phytohormonal regulation during stress responses.

The authors are thankful for the time you spent reading our manuscript.

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

Major comment

Although the review comprehensively summarizes phytohormone-mediated signaling pathways under abiotic stress, it provides limited discussion on how these hormonal regulatory networks can be practically exploited for crop improvement through biochemical, molecular, and biotechnological interventions. The manuscript would be substantially strengthened by including a dedicated section discussing translational approaches such as exogenous hormone priming; metabolic engineering; synthetic biology; marker-assisted breeding; and especially CRISPR/Cas-mediated genome editing of hormone biosynthesis, transport, receptor, and signaling genes. Integration of recent advances in editing ABA, auxin, ethylene, JA, and strigolactone-related pathways for improving drought, salinity, and heat tolerance would significantly enhance the novelty, applicability, and future perspective of the review.

Minor comments

Lines 30–31: The sentence “which are among the most significant limitations to crop growth and productivity worldwide” is somewhat generic and could be revised to a more precise scientific expression such as “major constraints on crop growth and productivity worldwide.”

Lines 31–33: The phrase “drought, salinity, extreme temperatures, and imbalances” is vague, particularly the term “imbalances.” The authors should clarify whether this refers to nutrient imbalance, ionic imbalance, or other environmental perturbations.

Lines 34–36: The statement “Recent global assessments indicate that such stresses account for nearly half of the observed yield losses in key agronomic crops” is overly broad and requires stronger supporting evidence. The authors should provide recent high-impact references, specify the crop systems or geographic scope being discussed, and avoid generalized quantitative claims unless supported by robust meta-analyses or global datasets.

Lines 37–39: The definition of drought stress as “sustained periods of below-normal soil moisture” is somewhat simplistic and does not fully capture the complexity of plant drought responses. The authors should consider including additional factors such as atmospheric water demand, evapotranspiration, developmental stage, and soil properties that collectively influence drought stress severity.

Lines 44–47: The description of heat stress effects remains largely descriptive and would benefit from inclusion of molecular mechanisms such as protein denaturation, ROS accumulation, heat shock protein induction, and membrane fluidity alterations. This would improve the mechanistic depth of the introduction.

Lines 52–57: The salinity stress section is scientifically acceptable; however, the discussion remains descriptive and could be strengthened by briefly mentioning ionic toxicity, Na+/K+ homeostasis, SOS signaling pathways, or osmotic stress signaling mechanisms.

Lines 63–66: The statement that “conventional breeding has shown limited success” is too generalized and potentially misleading. Significant progress has been achieved in breeding stress-tolerant cultivars in several crops. The statement should therefore be moderated and supported with more balanced discussion and recent references.

Lines 71–78: This section effectively summarizes major phytohormone-mediated responses under abiotic stress; however, it remains highly descriptive and lacks sufficient mechanistic integration. The Introduction would benefit from earlier mention of key signaling components such as ROS, Ca2+ signaling, MAPKs, SnRK2 kinases, transcription factors, and hormone receptor complexes.

Lines 79–83: The final objective statement is grammatically poor and requires revision for clarity. In particular, the phrase “While maintaining growth and productivity under unfavorable environmental conditions” appears incomplete and disconnected from the main sentence. The authors should revise this sentence to clearly state the scope, objectives, and novelty of the review article.

Lines 99–100: The sentence "Plants initiated rapid molecular signaling events” contains a grammatical inconsistency. It should be corrected (e.g., “plants initiate rapid molecular signaling events”).

Lines 130–132: The phrase “photosynthesis and respiration” is overly general. The authors may improve scientific depth by specifying impacts on photosystem stability, stomatal conductance, chloroplast ultrastructure, mitochondrial respiration, or Na+/K+ homeostasis.

Lines 155–158 / Figure 2: The figure legend refers to the “bZIP” transcription factor family, whereas the corresponding label inside Figure 2 is written as “BZIP.” The terminology should be standardized throughout the figure and legend for consistency.

Lines 165–166: The phrase “transport and nutrient movement” is somewhat vague. The authors should specify whether the phrase refers to membrane transport processes, phloem transport, ion transport, or aquaporin-mediated water movement.

Lines 204–206: The heat-shock protein section is scientifically sound; however, the manuscript could be improved by distinguishing among major HSP classes (e.g., HSP70, HSP90, small HSPs) and their specific protective roles under thermal stress

Lines 217–219 / Figure 4: The manuscript uses inconsistent notation for calcium ions throughout the text and figures (e.g., “Ca²⁺”, “Ca⁺⁺”, and “Calcium”). The authors should standardize calcium ion representation consistently throughout the manuscript and figures. The conventional scientific notation “Ca²⁺” is recommended for clarity and consistency with plant signaling literature.

Lines 229–494: Section 3 (“Phytohormones”) covers multiple hormone-mediated stress signaling pathways and hormonal interactions; however, the section would greatly benefit from the inclusion of a comprehensive integrative figure summarizing phytohormonal abiotic stress responses.

Lines 231–233: The sentence describing ABA biosynthesis is grammatically incomplete and scientifically unclear. In particular, the phrase “establishing a direct metabolic link between stress” appears truncated and should be revised for clarity and completeness.

Lines 231–233: The abbreviation “NCED” should be defined at its first occurrence as “9-cis-epoxycarotenoid dioxygenase (NCED).

Lines 463–494: The strigolactone section is informative, but the discussion would benefit from clearer explanation of SL biosynthesis, MAX signaling components, and interactions with ABA and auxin during abiotic stress adaptation

Lines 495–502: The introductory paragraph effectively introduces phytohormonal crosstalk during abiotic stress; however, the discussion remains highly condensed and would benefit from clearer conceptual framing distinguishing synergistic, antagonistic, and hierarchical hormone interactions.

Author Response

Reviewers' report and authors' answers for the manuscript submitted to Metabolites, MDPI, Special issue.

2^nd reviewer

Comments and Suggestions for Authors

We sincerely appreciate your time and expertise in reviewing our work. We have carefully considered your suggestions and revised the manuscript accordingly.

In the revised manuscript, changes are highlighted in yellow.

Below, we also provide a point-by-point response explaining how we have addressed each reviewer's comment.

Major comment

We sincerely thank the reviewer for this valuable suggestion. We agree that translational approaches such as hormone priming, metabolic engineering, synthetic biology, marker-assisted breeding, and CRISPR/Cas genome editing are highly important for improving abiotic stress tolerance in crops. However, we would like to clarify that the main scope of this review is the molecular and signaling mechanisms underlying phytohormone-mediated abiotic stress responses, with an emphasis on hormone biosynthesis, perception, signaling pathways, and crosstalk among major phytohormones. Therefore, the manuscript focuses on providing a mechanistic framework rather than detailed coverage of biotechnological and breeding applications. We believe that the topics suggested by the reviewer are better suited for a separate review specifically dedicated to translational and crop improvement strategies. We appreciate the reviewer’s comment, which highlights an important future direction in this field.

Minor comments

The requested change has been applied, and the revised sentence has been highlighted in yellow in the manuscript.

“Imbalances” was intended to refer to ion imbalances; however, to avoid ambiguity and in line with the reviewer’s suggestion, this term has been removed (highlighted in yellow on line 32). The sentence now focuses on drought, salinity, and temperature extremes, the main abiotic stresses addressed in this review.

The statement has been revised to address the concern by replacing the original broad claim with a more specific one supported by a recent meta-analysis (Wan et al., 2022). The corresponding changes have been highlighted in the manuscript (lines 35 and 36).

We agree that the initial definition in the Introduction was overly simplified and did not fully capture the complexity of drought stress in plants. However, due to the structural and length constraints of the Introduction section, it is not appropriate to provide an excessively detailed conceptual framework at that point. To address this, we have added a more comprehensive paragraph at the beginning of the drought section (lines 99–104), in which drought is defined more broadly, including soil moisture deficit, atmospheric demand, evapotranspiration, soil properties, and plant developmental stage.

In the Introduction, we aimed to provide a concise overview of heat stress effects, while detailed molecular and cellular mechanisms—including ROS accumulation, protein misfolding, membrane destabilization, heat shock signaling, and HSP induction—are discussed extensively in the dedicated “Heat Stress” subsection of the abiotic stress section. Nevertheless, to enhance the mechanistic depth of the Introduction, we have revised the text to briefly incorporate key molecular aspects of heat stress (lines 43–49).

The mechanistic aspects of salinity stress, including ionic toxicity, Na⁺/K⁺ homeostasis, the SOS signaling pathway, and osmotic stress signaling, have been comprehensively covered in the dedicated “Salinity” subsection of the abiotic stress section. In the introduction, only a brief overview of salinity stress and its overall effects on plant growth and productivity was provided to maintain structural clarity and avoid redundancy.

The sentence has been revised to provide a more balanced and accurate interpretation, acknowledging both the significant progress achieved through conventional breeding and the inherent limitations of conventional breeding in improving abiotic stress tolerance. The revised text is highlighted in yellow (lines 65–69). In addition, two recent references have been added to support this revised statement.

We have revised this section to enhance its mechanistic depth and clarity, as suggested. The Introduction now includes earlier and more explicit mention of key signaling components involved in phytohormone-mediated abiotic stress responses, including ROS, Ca²⁺ signaling, MAPK cascades, SnRK2 kinases, transcription factors, and hormone receptor complexes. The revised text has been highlighted in yellow (lines 74–80).

The sentence has been revised to improve clarity and grammar (lines 88–95). The incomplete phrase has been removed, and the statement has been rewritten to clearly define the objective of the review, including the roles of phytohormones in abiotic stress responses and their crosstalk and signaling interactions.

The sentence has been corrected in line 119 (“initiated” → “initiate”).

We have added a new paragraph (lines 152–161) to provide a more detailed and mechanistic description of the effects of salinity stress on key physiological and cellular processes.

The abbreviation has been standardized throughout the manuscript and in the figure as “bZIP” for consistency.

The sentence has been revised to clarify which transport processes are affected by cold stress, including ion transport and aquaporin-mediated water movement (lines 193–196).

We have revised the manuscript by adding a new paragraph that more clearly distinguishes the major heat-shock protein classes and their specific protective roles during thermal stress, including HSP70, HSP90, and sHSPs. The added section is highlighted in yellow in lines 236–245.

Lines 217–219 / Figure 4: The manuscript uses inconsistent notation for calcium ions throughout the text and figures (e.g., “Ca²⁺”, “Ca++”, and “Calcium”). The authors should standardize calcium ion representation consistently throughout the manuscript and figures. The conventional scientific notation “Ca²⁺” is recommended for clarity and consistency with plant signaling literature.

The notation for calcium ions has been standardized throughout the manuscript and figures as “Ca²⁺” to align with the plant signaling literature, and Figure 4 has been revised accordingly. Exceptions include the first mention of “calcium” in the text for clarity (followed by Ca²⁺), as well as established terms such as “calcium-dependent protein kinases” and phrases like “calcium-dependent signaling cascade/pathway,” where “calcium” is retained as part of accepted biological nomenclature.

A comprehensive integrative figure summarizing phytohormone-mediated abiotic stress signaling pathways and their crosstalk has already been included in Section 4 (Figure 5). It collectively illustrates the interactions among the major hormonal networks under stress conditions.

The sentence has been revised to improve grammatical structure and scientific clarity. The changes appear in lines 268–271.

Lines 231–233: The abbreviation “NCED” should be defined at its first occurrence as “9-cis-epoxycarotenoid dioxygenase (NCED).

The abbreviation NCED has been defined at its first occurrence in the revised manuscript (lines 265 and 266) as 9-cis-epoxycarotenoid dioxygenase (NCED).

we have revised and reorganized the strigolactone section to improve clarity and logical flow. The text has been rewritten so that SL biosynthesis, perception/signaling via the MAX2-dependent pathway, and hormonal crosstalk with ABA and auxin during abiotic stress are presented in a clearer and sequential manner. The beginning of each section has been highlighted in yellow.

A new paragraph has been added to the section (lines 539–559) to clarify and distinguish among synergistic, antagonistic, and hierarchical phytohormonal interactions, thereby improving the conceptual framework of the discussion.

Authors are thankful for the time you spent reading our manuscript.

25.5.2026

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

Dear Authors,

The peer-reviewed article “Phytohormonal Regulation of Plant Responses to Abiotic Stress: From Signalling Pathways to Hormonal Crosstalk” addresses the important issue of hormonal regulation in plants exposed to abiotic stress. However, the article requires substantial revision before it can be accepted for publication, as it lacks many key points.

Why do the authors describe only certain types of abiotic stress? For example, stresses caused by heavy metals, nutrient deficiencies, exposure to UV radiation, exposure to O3 and flooding are missing. This should be corrected or the title of the article should be changed to avoid confusion.
Why have the authors not described key hormones such as cytokinins and brassinosteroids?
The article should also contain more detailed information on the interactions and antagonisms between hormones. Greater emphasis should also be placed on the importance of hormonal balance.
I suggest writing an article about plant adaptation and acclimatisation.
Please include information on modern research approaches (transcriptomics, metabolomics or proteomics).
The paper clearly lacks practical relevance (agriculture, breeding of stress-tolerant plants, the effect of biostimulants and exogenous growth regulators).
The authors should describe gaps in knowledge and prospects for further research.
There is no separate ‘Conclusions’ section at the end of the paper to provide a summary.

Author Response

Reviewers' report and authors' answers for the manuscript submitted to Metabolites, MDPI, Special issue.

3^rd reviewer

Comments and Suggestions for Authors

Dear Authors,

We express our sincere appreciation to you for investing your time and expertise in reviewing our work. We have carefully considered your suggestions and revised the manuscript accordingly.

Changes in the revised version of the manuscript are highlighted in yellow. Below, we also provide a point-by-point response explaining how we have addressed each of the reviewer comments.

Why do the authors describe only certain types of abiotic stress? For example, stresses caused by heavy metals, nutrient deficiencies, exposure to UV radiation, exposure to O3 and flooding are missing. This should be corrected or the title of the article should be changed to avoid confusion.

We fully agree that abiotic stress is a broad category that includes heavy metal toxicity, nutrient deficiency, UV radiation, ozone exposure, and flooding, all of which are important in plant stress biology. However, the present review was designed with a focused scope on the most extensively studied and agronomically important stresses, particularly drought, salinity, and temperature extremes. These stresses are among the most yield-limiting factors in global agriculture and are also among the most extensively studied in the context of phytohormonal signaling and crosstalk, allowing for a more coherent and mechanistic discussion.

In addition, this review builds on our previous research in salinity stress physiology, which further guided our focus on salt- and related-stress signaling pathways. To address the reviewer’s concern, we have revised the manuscript title, replacing “abiotic stress” with “major abiotic stresses” (lines 2 & 3), to better reflect the scope of the review and avoid potential misunderstanding.

Why have the authors not described key hormones such as cytokinins and brassinosteroids?

The scope of this review focused on key phytohormones that form the main regulatory network in plant responses to abiotic stress and hormone crosstalk. We included ABA, JA, SA, ET, and IAA, which are core hormones involved in stress perception, signaling, and response. We also included gibberellins because they are well known for balancing growth and stress and for interacting with major stress-related hormones. We also included emerging hormones, such as melatonin and strigolactones, because their roles in abiotic stress are increasingly recognized and being studied more widely.

We did not exclude cytokinins and brassinosteroids because they are unimportant, but because their roles in abiotic stress are more context-dependent and less consistently part of the core stress signaling network than those of the hormones we focused on. To keep the discussion focused and mechanistically clear, we prioritized the hormones mentioned above.

The article should also contain more detailed information on the interactions and antagonisms between hormones. Greater emphasis should also be placed on the importance of hormonal balance.

A new paragraph has been added to Section 4 (lines 539–559) to provide a more detailed discussion of hormonal interactions, including synergistic, antagonistic, and hierarchical relationships among phytohormones. This addition also highlights the importance of dynamic hormonal balance in coordinating growth and stress responses.

I suggest writing an article about plant adaptation and acclimatisation.

We thank the reviewer for this helpful suggestion. This is an interesting and valuable topic, and we will take it into account for future work.

Please include information on modern research approaches (transcriptomics, metabolomics or proteomics).

We agree that transcriptomics, proteomics, and metabolomics have greatly advanced our understanding of plant responses to abiotic stress and phytohormone signaling.

However, the main focus of this review is on the molecular mechanisms underlying phytohormone-mediated stress responses, particularly hormone biosynthesis, signaling pathways, and hormonal crosstalk. Accordingly, the manuscript is intended to provide a mechanistic overview rather than a discussion of omics methods. A detailed discussion of transcriptomics, proteomics, and metabolomics would significantly broaden the scope of the review and require coverage beyond the present manuscript's aim.

Nevertheless, we recognize the importance of these approaches and have added a brief statement in the conclusion (lines 636–641) that highlights their potential role in future studies of phytohormone-mediated stress responses.

The paper clearly lacks practical relevance (agriculture, breeding of stress-tolerant plants, the effect of biostimulants and exogenous growth regulators).

As noted above, the primary aim of this review is to elucidate the molecular mechanisms underlying phytohormone-mediated responses to abiotic stresses. Accordingly, the manuscript focuses on signaling pathways, hormonal crosstalk, and molecular regulation rather than applied agricultural topics such as breeding strategies or field applications of biostimulants. Topics such as breeding stress-tolerant crops, developing and optimizing biostimulants, and applying exogenous plant growth regulators are broad, multidisciplinary research areas spanning agronomy, biotechnology, and field-based studies. A detailed review of metabolites.

The authors should describe gaps in knowledge and prospects for further research.

This section (future perspective and challenges) has been added to the end of the review (page 17) and highlighted in yellow.

There is no separate ‘Conclusions’ section at the end of the paper to provide a summary.

A separate “Conclusions” section is already included in the manuscript and appears on page 16.

The authors are thankful for the time you spent reading our manuscript.

Authors

25.5.2026

Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

Comments and Suggestions for Authors

Although the authors have clarified that the primary focus of the review is on mechanistic aspects of phytohormone-mediated abiotic stress signaling, the manuscript would still benefit from at least a brief concluding perspective on how these signaling pathways and regulatory networks can be manipulated for crop improvement. Since the review extensively discusses hormone biosynthesis, perception, signaling, and crosstalk mechanisms, inclusion of a concise section highlighting the translational relevance of these pathways would provide better completeness and broader impact to the article.

In particular, the authors are encouraged to briefly discuss how key hormonal signaling components (e.g., biosynthetic enzymes, receptors, transporters, transcription factors, and downstream regulators) are being targeted through modern approaches such as CRISPR/Cas-mediated genome editing, molecular breeding, or pathway engineering to enhance abiotic stress tolerance. Even a short perspective covering manipulation of ABA, auxin, ethylene, jasmonic acid, or strigolactone signaling modules under drought, salinity, and heat stress would substantially improve the future outlook and applicability of the review without deviating from its mechanistic focus.

Other previously raised concerns appear to have been adequately addressed.

Author Response

Reviewers report from Metabolites!

Reviewer 2, Round 2

Comments and Suggestions for Authors

We appreciate the reviewer’s valuable suggestion. The manuscript has been updated to include an additional perspective in the Future Perspectives and Challenges section (lines 651–672) on the practical applications of phytohormone signaling to enhance crop stress tolerance.

This addition highlights how recent advances in genome editing, breeding strategies, and pathway-level engineering can be used to target key regulatory nodes in hormonal networks.

Other previously raised concerns appear to have been adequately addressed.

We appreciate the reviewer’s positive assessment and are grateful that the revisions are satisfactory.

Authors

1.6.2026

Author Response File: Author Response.docx

Reviewer 3 Report

Comments and Suggestions for Authors

Dear Authors,

The authors have addressed all of the reviewer's comments. I recommend accepting the work in its current form.

Author Response

Thank you very much for your time and constructive assessment and review of our manuscript.

Authors

28.5.2026

Author Response File: Author Response.pdf