Overexpression of ONAC054 Improves Drought Stress Tolerance and Grain Yield in Rice
Round 1
Reviewer 1 Report
Manuscript presents high-quality researches providing evidence for the involvement of a transcriptional factor (ONAC054) in the control of osmotic stress response of seedlings and the response of mature plants to drought.
The strongest side if the paper are comprehensive molecular studies presenting in an excellent way evidence of altered expression patterns of relevant to the response genes in wild plants, mutants and transgenic plants with overexpression of the gene when exposed to the stress.
This studies are the extension of earlier reports showing that the ONAC054 gene is related to the ABA synthesis and signalling and to ABA-dependent senescence as well as studies on the role of NAC in the drought-tolerance in Arabidopsis.
The authors show also agronomic consequences of manipulation with the gene, which may have even potentially practical significance in some future with respect of efforts to improve crops tolerance to drought, a stress of primary significance in the worldwide scale.
The response of seedling was measured by ion leakage and MPA content. The former is often used to get evidence of membrane damage. However, justification of use the latter test is less obvious and it would be worth to add some comments why this test was chosen and what it proved.
The article fits into the issues of understanding molecular mechanisms underlying abiotic tolerance and crop improvement and thus to the crops journal.
The manuscript is very well written and almost ready for publication. All conclusions are well supported by the data.
Author Response
Responses to comments raised by reviewer 1
>The response of seedling was measured by ion leakage and MPA content. The former is often used to get evidence of membrane damage. However, justification of use the latter test is less obvious and it would be worth to add some comments why this test was chosen and what it proved.
Thanks for your valuable advice. Similar to ion leakage rate, MDA content is also used as a marker of membrane damage caused by environmental stresses since MDA is one of the final products of lipid peroxidation in the cells. In the revised manuscript, we have added an explanation of the purpose of the measurement of ion leakage rate and MDA content.
Reviewer 2 Report
The manuscript entitled “Overexpression of ONAC054 Improves Drought Stress 2 Tolerance and Grain Yield in Rice” reports a genuine piece of fundamental research work. The study has gained great scientific insights involved in the drought stress response. Overall; the MS is well written, easy to follow and well structured. It’s a pleasure to read and I congratulate the authors of the MS for that. However, there are a few points need to be addressed to clarify the results better. The current wordings may cause confusions to readers.
1. Figure 1 and its relevant result section (page 6, line 227-242):
a. There are 2 Figure 1D, pls rename them
b. It seems like the result section does not match with the figure 1D (2nd one) to F. Pls check and re-write this section.
c. Figure 1A and B: Although ONAC054β was induced much faster than ONAC054α but the expression of ONAC054α was higher in later stages. Would the authors would like to comment on that?
2. Page 5, line 194: “we first examined monitored the expression…” should be written as “we first examined/monitored the expression…”
3. Page 5, line 253-254: Authors of the MS said “the expression levels of CYP707A6 and CYP707A7, encoding ABA catabolic enzymes, were slightly decreased”. Do you have any statistical analysis to support that? What does “slightly” mean here?
4. Figure 6G: More explanation would be needed. Percentage of germination, numbers of germinated seeds/100 seeds etc. would be useful for readers.
Author Response
Responses to comments raised by reviewer 2
> Figure 1 and its relevant result section (page 6, line 227-242): There are 2 Figure 1D, pls rename them. It seems like the result section does not match with the figure 1D (2nd one) to F. Pls check and re-write this section.
Thank you very much for pointing out our serious errors. In the revised manuscript, we have changed the order of three graphs from ion leakage rate, MDA content, and fresh shoot weight (D, E, F in the first draft) to fresh shoot weight, ion leakage rate, and MDA content (E, F, G in the revised manuscript). In addition, we have revised the relevant sentences.
>Figure 1A and B: Although ONAC054β was induced much faster than ONAC054α but the expression of ONAC054α was higher in later stages. Would the authors would like to comment on that?
Following your advice, We have revised the sentence to “However, their expression patterns during dehydration stress were somewhat different: ONAC054β was induced much faster than ONAC054α, while the expression of ONAC054α was much higher than that of ONAC054β in the later stage of dehydration (Figure 1A).”
>Page 5, line 194: “we first examined monitored the expression…” should be written as “we first examined/monitored the expression…”
We have revised to “we first examined the expression…”.
>Page 5, line 253-254: Authors of the MS said “the expression levels of CYP707A6 and CYP707A7, encoding ABA catabolic enzymes, were slightly decreased”. Do you have any statistical analysis to support that? What does “slightly” mean here?
We have revised the sentence to “whereas the expression levels of CYP707A6 and CYP707A7, encoding ABA catabolic enzymes [44], were not significantly changed”.
>Figure 6G: More explanation would be needed. Percentage of germination, numbers of germinated seeds/100 seeds etc. would be useful for readers.
Images in Figure 6G show the total amount of seeds harvested and the ratio of filled seeds to unfilled seeds of rice grown under control and dehydration stress conditions. We have changed (Figure 6F) in line 470 to (Figure 6F and 6G), and (Figure 6D and 6E) in line 473 to (Figure 6D, 6E, and 6G). On the other hand, in this study, we did not conduct the germination test using the seeds of onac054-KO and ONAC054-OX. While ABA also affects seed germination, in this study, we mainly, focused on the function of ONAC054 in drought stress responses.
