Analyzing Single and Combined Cultures of Plant Growth-Promoting Rhizobacteria Isolates from Afghanistan as a Potential Biofertilizer for Rice Growth and Development

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

 This study examined single and combined application effects of four plant growth-16 promoting rhizobacteria (PGPR) strains on nitrogen (N2) fixation, indole-3-acetic acid (IAA), organic 19 acid production, and P and K solubilization. I think it is a meaningful research, providing useful information of single or combined strains- application of biofertilizer for agriculture. There are several minor questions listed as follows:

2.2 why use rpoB gene as a complementary marker?

2.8 for single and combined cultures experiments , it seems the cell density is the same, but the volumes of the added cultures were not provided.

3.5 and 3.6 In a previous  study, AF124 did not show P-solubilization activity and K -solubilization activity, but in the present study, this strain showed opposite results, so why this happened?

Author Response

Please see the attached PDF file for the answer to the comments to the reviewer 1.

 

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

Developing multi-functional, environmentally friendly biofertilizers can help reduce chemical fertilizer usage. The authors investigated the physiological features of single and combined four plant growth-promoting rhizobacteria (PGPR) strains. The effects of PGPRs on plant growth were also examined. They found single and combined PGPR treatments have different physiological features, but all single and combined PGPRs increased plant growth. However, after reading the whole manuscript, I found that the description of the effects of PGPRs on plant growth and the discussion of the underlying mechanisms are not adequate. The below are some specific comments.

1.      Line 28-29. It seems single and combined PGPR treatments showed different effects on plant growth. I think more details of the effects of PGPR on plant growth should be described. Moreover, are there any correlations between the properties of PGPR and their effects on plant growth?

2.      Line 78-82. The physiological characteristics and effects on plant performance of 4 PGPRs have been studied as reported in the reference [34]. Rice growth was also studied in the reference [34]. What are the differences between this study and the reference [34]?

3.      Line 163-188. Did the experiment include a control treatment? How control treatment was conducted?

4.      Line 288-290. Please pay attention to the grammar in this sentence.

5.      Line 173. I am curious why one Afghan rice variety was selected in this study?

6.      Table 1 is not the main data. I think it should be displayed in supplementary material. In addition, data should be displayed as mean±SD/SE.

7.      Line 362-370. The effects of PGPRs on plant growth should be discussed more extensively. For example, why PGPRs increased plant growth in nutrient-sufficient soils?

8.      Line 369-370. References should be cited.

Author Response

Please see the attached PDF file for the answer to the comments to the reviewer 2.

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

L54-55- The statement needs modification. You can’t make this claim, microbial consortium is well established concept.

L68-71: Have you checked other PGP activities in these stains ?

L107 Rename this section as “Compatibility study”

L116: What is NFb? Elaborate when abbreviations are used for first time in the MS.

L137: What was the P source?

Table 1: Indicate error values.

 

L272: The plant data is insufficient. Some more data is required especially on N, P, K content/uptake in the plants and changes in the expression of related genes, etc.  

Author Response

Please see the attached PDF file for the answer to the comments to the reviewer 3.

Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

Comments and Suggestions for Authors

Authors have addressed my initial concerns.

Author Response

Attached please find our answer to the comments which the editor suggested to revise. 

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

The experiment data is insufficient and the reply did not provide such data that makes the paper fit to be accepted

Author Response

Attached please find our answer to the comments which the editor suggested to revise. 

Author Response File: Author Response.pdf