Advances in Understanding Salt Stress Effects on Growth and Productivity in Sorghum (Sorghum bicolor L. Moench)

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

The manuscript “Advances in Understanding Salt Stress Effects on Growth and Productivity in Sorghum (Sorghum bicolor L. Moench)” have scientific worth, however it required significant revisions.

Detail summary:

This manuscript presents a narrative review synthesizing 44 recent studies (2021-2026) on salinity stress responses in sorghum, employing a PRISMA-informed screening approach. The review covers germination, vegetative growth, physiological and biochemical responses, ion homeostasis, molecular mechanisms, productivity, and management strategies. Key contributions include: (i) timely synthesis of recent omics and GWAS findings; (ii) comprehensive coverage of traits across the sorghum life cycle; (iii) integration of genetic and agronomic perspectives; and (iv) practical breeding and management recommendations. However, revisions are required.

Detailed Evaluation of Methodology, Analyses, and Conclusions

Methodology: The PRISMA-informed screening approach enhances transparency, and the authors appropriately acknowledge that meta-analysis was unsuitable given study heterogeneity. However, significant methodological limitations exist: (i) the review treats salinity as a relatively uniform stress without systematically differentiating saline, sodic, and saline-sodic conditions—a distinction that fundamentally affects tolerance mechanisms, genotype rankings, and management interventions; (ii) no formal quality assessment tool was applied to the 44 included studies; (iii) the criteria for study inclusion are applied qualitatively without explicit scoring or sensitivity analyses.

Analyses: The synthesis is thematic rather than quantitative, which is appropriate given heterogeneity. However, the review lacks effect size reporting (e.g., "reduced germination" without quantifying the reduction), does not critically evaluate trait redundancy or cost-effectiveness, and does not address temporal dynamics such as stress duration, timing, or recovery capacity. The proposed integrated tolerance mechanism model (Figure 4) is heuristic but lacks quantitative validation or confidence ratings for pathway interactions.

Conclusions: While the conclusions broadly align with the evidence presented, they are overly general and do not adequately distinguish findings by salinity type, study environment (field vs. controlled), or stress duration. The manuscript claims to bridge laboratory findings to field applications but does not quantify the proportion of studies conducted under field conditions or provide evidence that controlled-environment findings translate to field performance.

Areas need to be improved (Reviewer comments)

1. Restructure the Review by Salinity Type

Issue: The manuscript treats salinity as homogeneous, yet saline, sodic, and saline-sodic soils differ fundamentally in chemistry, tolerance mechanisms, and management.

Action Required: Create distinct subsections or clearly differentiate findings by salinity type throughout the review. Explicitly state which of the 44 studies address each condition. Discuss whether genotype rankings differ between saline and sodic conditions and how conclusions change when sodicity is considered. Provide a decision matrix linking soil diagnosis to management strategies.

2. Address Temporal Dynamics of Salinity Stress

Issue: Salinity is presented as a static stress, but field conditions involve variable duration, timing, and recovery periods.

Add a subsection on temporal dynamics addressing: (i) acute vs. chronic salinity effects; (ii) stress timing relative to phenological stage (emergence, flowering, grain filling); (iii) recovery capacity after stress relief (e.g., rainfall, leaching); (iv) sequential stress interactions (salinity followed by drought, heat during salinity); and (v) cumulative effects across seasons.

3. Quantify Key Findings

Issue: The abstract and conclusions are descriptive without quantification (e.g., "lower germination rate" without specifying magnitude).

Authors provide effect size ranges throughout the review. For example: "NaCl at 60-200 mM reduced germination by 20-40%, root and shoot elongation by 25-50%, and biomass by 20-55% compared to controls." Quantify tolerance differences between genotypes (e.g., "tolerant lines maintained K⁺/Na⁺ ratios 2-5× higher than sensitive lines").

4. Evaluate Study Comparability and Field Validity

Issue: The manuscript does not critically assess whether the 44 studies are comparable or how findings translate to field conditions.

I suggest authors create a supplementary table detailing for each study: salinity type, concentration/EC, duration, growth stage, environment (field/pot/hydroponics), genotypes, and key outcomes. Quantify the proportion of studies conducted under field vs. controlled conditions. Explicitly state which conclusions are supported by field evidence and which require validation. Discuss whether genotype rankings observed in controlled conditions correspond to field rankings.

5. Provide Trait Utility Analysis for Breeding Programs

Issue: Many tolerance traits are listed (Table 2) but not prioritized for practical breeding applications.

Action Required: Rank traits by cost-effectiveness, heritability, throughput, and predictive value for yield. Identify redundant traits (e.g., are SOD, CAT, and POD assays providing independent information or are they highly correlated?). Recommend minimal trait sets for different purposes: initial screening vs. detailed breeding evaluation vs. management decisions.

6. Strengthen Molecular and Omics Evidence Section

Issue: The molecular discussion would benefit from additional context on broader crop salt-tolerance strategies and recent biotechnological advances.

Action Required: Cite Yuan et al. (2024, "Genomic and Modern Biotechnological Strategies for Enhancing Salt Tolerance in Crops") to contextualize sorghum-specific findings within the broader crop salt-tolerance literature and to strengthen the discussion of functional validation and translational research.

7. Strengthen Management and Plant-Microbe Interactions Section

Issue: The discussion of PGPR and microbial interventions is valuable but could be enhanced with mechanistic and strategic context.

Action Required: Cite Shi et al. (2024, "Insights into plant–microbe interactions in the rhizosphere to promote sustainable agriculture in the new crops era") to strengthen the mechanistic understanding of why microbial effects are genotype- and environment-dependent and to provide a strategic framework for integrating microbial interventions.

8. Strengthen Breeding Implications and Translational Research Section

Issue: The breeding discussion would benefit from recent advances in AI-driven genomic prediction.

Action Required: Cite Feng et al. (2024, "AI breeder: Genomic predictions for crop breeding") to strengthen the discussion of genomic selection, multi-environment prediction, and the integration of machine learning into sorghum salinity breeding programs.

9. Provide an Integrated Management Decision Framework

Issue: The manuscript discusses multiple management strategies (priming, biochar, gypsum, PGPR, irrigation) but does not provide guidance on how to integrate them based on site-specific conditions.

Action Required: Develop a decision framework that specifies: (i) which strategies are appropriate for saline vs. sodic vs. saline-sodic soils; (ii) the correct sequencing of interventions (e.g., gypsum before leaching); (iii) conditions where each strategy is contraindicated; and (iv) economic considerations (cost, labor, resource availability) affecting farmer adoption.

10. Update Conclusions with Specific, Quantified Statements

Issue: Conclusions are broad and vague.

Action Required: Revise conclusions to provide specific, quantified statements differentiated by salinity type, stress duration, and environment. Example: "Under saline conditions (EC 4-12 dS/m), tolerant sorghum genotypes maintained 40-60% higher biomass and 30-50% higher grain yield than sensitive lines, primarily through K⁺/Na⁺ homeostasis. However, only X of 44 reviewed studies were field-based, and genotype rankings differed between saline and sodic conditions, indicating that breeding programs must consider target soil conditions. Future priorities include field validation of candidate genes, integrated management packages for specific salinity types, and adoption of AI-driven genomic prediction."

11. Revise Figures and Tables for Clarity

• Figure 4 (Integrated tolerance mechanism model): Add confidence ratings for each pathway based on evidence strength. Distinguish between well-established pathways and hypothetical interactions. Consider adding a complementary figure showing temporal dynamics.
• Table 1: Add columns for "Salinity type (saline/sodic/saline-sodic)" and "Study environment (field/pot/hydroponics)." Provide quantitative details (e.g., NaCl concentration, trait response magnitude).

Overall Assessment

The manuscript addresses an important and timely topic, compiling valuable contemporary evidence on sorghum salinity responses. However, significant revisions are required to address: (i) inadequate differentiation among salinity types; (ii) static rather than dynamic stress conceptualization; (iii) lack of quantitative synthesis and effect size reporting; (iv) insufficient critical evaluation of study comparability and field validity; and (v) limited translation to practical, field-applicable recommendations. With revisions addressing above points, the manuscript could make a substantial contribution to the field. "

Author Response

Please see the attachment

Author Response File: Author Response.docx

Reviewer 2 Report

Comments and Suggestions for Authors

The topic of the present manuscript is interesting and relevant, as salinity is an important problem for crop productivity and sorghum has strong potential for cultivation in stress-affected areas. Overall, the review is clearly organized and covers several important aspects, including germination, physiological responses, ion homeostasis, molecular evidence, breeding and management strategies. The focus on productivity is also useful and important, as it connects stress responses with agronomic performance. However, there are some issues that need to be addressed before the article is recommended for publication.

MAJOR COMMENTS

- Careful language editing is recommended before publication. Although the main message is generally understandable, several sentences need revision because the wording is not always clear and some points are difficult to follow. For example, in the Research Gaps section, the sentence “Mechanistic results rely on this information to be difficult to extrapolate to field management” (L561-L562) should be rewritten. Similarly, in the Conclusions, phrases such as “In the most powerful tolerance characteristics, the concept of integration is more important than individualism” (L603-604) are difficult to understand in their current form, etc.

- The review methodology also needs some clarification. The manuscript is presented as a systematic review, but the Methods describe it as a structured narrative review using PRISMA-informed screening principles. In addition, the PRISMA-style search and screening numbers should be checked carefully. In the text, it is reported that 142 records were identified through database/publisher searches and 18 additional records through citation chasing and journal pages (therefore, a total of 160), but Figure 1 only clearly shows 142 identified records. In addition, the figure reports 18 records removed before screening and 118 records screened, although 142 minus 18 would give 124. The full-text exclusion numbers also need correction: the text lists exclusion categories adding up to 10, while Figure 1 reports 11 exclusions with different category numbers. Please revise the text and Figure 1 so that all screening numbers and exclusion categories are fully consistent.

- The manuscript has a useful focus on productivity, rather than only on early stress-response traits. However, the evidence supporting this point should be presented more clearly. The authors state that the included sources were coded by evidence type, growth stage, salinity level, main trait and tolerance implication, but this coding is not fully shown in the manuscript. I suggest adding a table (in the main text or in the Supplementary Materials) summarizing the 44 included studies according to these categories. This would help the reader distinguish studies based mainly on early-stage or controlled-condition traits from studies that include biomass, forage, reproductive or yield-related data.

MINOR COMMENTS

- L50: Please change “bicolour” to the correct “bicolor”.

- L61-64 “Saline stress results in better germination…”: The phrasing here is confusing and rather misleading. Do the authors probably mean that some genotypes maintain better performance under salinity? Please rephrase and clarify.

- L192: The text refers to “recent salinity reviews (Table 1)”, but Table 1 summarizes recent sorghum salinity, mostly experimental, studies. Please rephrase.

- L258-260 “The tolerable seedling…”: This should probably be rephrased to “a salt-tolerant seedling” or “a tolerant seedling”.

- L507-508 “improved irrigation…in the root zone of trees”: Since the manuscript is about sorghum, “trees” should probably be corrected to “crops”, “plants” or simply “root zone”.

- L550-551 “Calibration of remote…salinity conditions”: This sentence appears to be incomplete and needs to be rewritten.

- Please make sure that each reference in the reference list also includes an active, accessible link (e.g. references 17 and 33 are missing one).

Comments on the Quality of English Language

Careful language editing is recommended before publication. Although the main message is generally understandable, several sentences need revision because the wording is not always clear and some points are difficult to follow. For example, in the Research Gaps section, the sentence “Mechanistic results rely on this information to be difficult to extrapolate to field management” (L561-L562) should be rewritten. Similarly, in the Conclusions, phrases such as “In the most powerful tolerance characteristics, the concept of integration is more important than individualism” (L603-604) are difficult to understand in their current form, etc.

Author Response

Please see the attachment

Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

Comments and Suggestions for Authors

My main concerns have been addressed by the authors. The revised version of the manuscript appears to be technically improved and provides clearer information on the review methodology. This makes the article easier to follow and strengthens the overall structure of the review. However, although the language has also improved compared with the previous version, several incorrect expressions and grammatical issues remain. Careful language editing is still recommended before publication. Some (but not the only) examples:

- L42 "Salinity is one of the most endemic environmental factors of crop productivity...": The use of the term "endemic" is not appropriate here.

- L86-87 "The paper therefore updates the perspective because it considers productivity as the main outcome and resorts to mechanisms only those that explain agronomic performance.": This sentence has grammar issues and needs to be rewritten.

- L218 "However, in recent sorghum salinity (Table 1)..." : This needs to be rewritten.

- L231-232 "One key finding from new research is that sorghum should not be categorized as salt-tolerant, but rather salt-tolerant and salt-responsive." : This is confusing because “salt-tolerant” is repeated.

- L568-569 "The best contribution is not to mention these interventions but to see them as decision points related to soil diagnosis and crop target." The phrasing here is confusing. The sentence needs to be rewritten.

etc.

 

Comments on the Quality of English Language

However, although the language has also improved compared with the previous version, several incorrect expressions and grammatical issues remain. Careful language editing is still recommended before publication. Some (but not the only) examples:

- L42 "Salinity is one of the most endemic environmental factors of crop productivity...": The use of the term "endemic" is not appropriate here.

- L86-87 "The paper therefore updates the perspective because it considers productivity as the main outcome and resorts to mechanisms only those that explain agronomic performance.": This sentence has grammar issues and needs to be rewritten.

- L218 "However, in recent sorghum salinity (Table 1)..." : This needs to be rewritten.

- L231-232 "One key finding from new research is that sorghum should not be categorized as salt-tolerant, but rather salt-tolerant and salt-responsive." : This is confusing because “salt-tolerant” is repeated.

- L568-569 "The best contribution is not to mention these interventions but to see them as decision points related to soil diagnosis and crop target." The phrasing here is confusing. The sentence needs to be rewritten.

etc.

Author Response

Please see the attachment.

Author Response File: Author Response.docx