Tomato and Pepper Seeds as Pathways for the Dissemination of Phytopathogenic Bacteria: A Constant Challenge for the Seed Industry and the Sustainability of Crop Production
Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsThe tomato and pepper seeds contamination, endophytic colonization, bacterial infection were focused in this review. And the treatments and disinfection methods were concluded further. So it is very important and valuable for seed industry. This review is comprehensive to some extent, however, it reads like a textbook. So the authors can summarize and give concise expression. The references are too many.
Author Response
Dear Revier 1,
Thank you very much for taking the time to review this manuscript. Please find the detailed responses below and the corresponding revisions/corrections highlighted/in track changes in the re-submitted files.
Response 1: Thank you for pointing this out. We have accordingly deleted or summarized several parts to give more concise expression. Please see in tracking changes all the revised/deleted parts: Lines 151-152; Lines 181-183; Lines 192-194; Lines 204-206; Lines 216-222 (moved to further section, Lines 308-314); Lines 235-236; Lines 270-272; Lines 282-284; Lines 299-304; Lines 314-317; Lines 325-331; Lines 681-682.
Response 2: According to reviewer’s comments, 39 references considered as not essential have been removed. Please find the following removed refences:
7. Lines 917; 21. Lines 947-950; 22. Lines 949-950; 26. Lines 957-958; 27. Lines 959-961; 28. Lines 962-964; 37. Lines 984-986; 41. Lines 994-995; 43. Lines 999-1002; 48. Lines 1010-1012; 49. Lines 1013-1015; 55. Lines 1027-1028; 58. Lines 1035-1037; 59. Lines 1038-1041; 63. Lines 1051-1052; 66. Lines 1057-1058; 71. Lines 1070-1071; 72. Lines 1072-1074; 75. Lines 1079-1081; 76. Lines 1082-1083; 77. Lines 1084-1085; 78. Lines 1086-1087; 79. Lines 1088-1090; 80. Line 1091; 81. Line 1092; 82. Lines 1093-1094; 91. Lines 11112-1113; 92. Lines 1114-1116; 93. Lines 1117-1119; 98. Lines 1129-1130; 115. Lines 1171-1172; 119. Lines 1179-1181; 125. Line 1200; 127. Lines 1205-1206; 135. Lines 1224-1226; 139. Lines 1239-1240; 145. Lines 1250-1251; 169. Lines 1301-1302; 174. Lines 1312-1313.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
Comments and Suggestions for AuthorsThis review manuscript entitled as 'Tomato and pepper seeds as pathways for the dissemination of phytopathogenic bacteria: a constant challenge for the seed industry and the sustainability of crop production' is good written and reviews important topics on seeds. However, i highly recommend the authors to broaden this manuscript with more relevant information on seed systems as this is a review paper. recommendation/suggestions"
1. a general introductory section on seeds regulations - SMATA?
2. Review the possible effect of seed treatments on the beneficial endophytes?
3. Role of resistance / tolerant germplasm? You know especially some tomato cv. have resistant genes to pest and diseases!
Comments on the Quality of English Language
English language can be improved.
Author Response
Dear Reviewer 2,
Thank you very much for taking the time to review this manuscript. Please find the detailed responses below and the corresponding revisions/corrections highlighted/in track changes in the re-submitted files.
Response 1: Thank you for pointing this out. We agree with this comment. Therefore, we added a paragraph in the introductory part with some considerations on the recent, important changes faced by the seed industry; particularly, we focused on the innovations required by the fourth agricultural revolution and how this might impact the sustainability of seed production for the global market in low-income countries in terms of the current regulatory background and considering the SMATA. The following paragraph has been added in pp. 2 – 1. Introduction - new lines 50-72: “The seed “industry” greatly developed in the last few decades: from the use of traditional genotypes restricted in small areas or regions that didn’t take advantage of any emergent technology for seed production, to the breeding of modern cultivars that suits the need of high yield crop plants, resilient to the challenges posed by a changing climate, and adaptable to the most different environments. Therefore, this jump required the transition to a modern seed production chain by the development and use of technologies emerged from the fourth agricultural revolution and by the implementation of a multifaceted international regulatory background [6]. Indeed, the structure of the seed industry changed, from a high number of small regional enterprises to a few big global players: these are currently able to introduce and implement advanced seed production chains, involving multiple actors and extending in several countries over the five continents (Figure 1). Then, market globalisation and the need to pursue food security and safety, required a trans-disciplinary approach by such multistakeholder sector. The current efforts by the seed industry, besides breeding high yield crop plants, is also directed to the development of sanitation methods to avoid the dissemination of seed associated pests, from area to area and from country to country. An assessment of the impact of such industrial development (e.g. the application of innovative sanitation methods) on country and society is still missing: indeed, a Sustainable Modern Agriculture Technology Assessment (SMATA) is desirable [7], for instance to study the impact of massive production of tomato and pepper seeds on behalf of the major global players in low income countries, on their society and rural communities; this might greatly help governmental bodies and organisations to make appropriate decisions and advocate the involvement of a larger group of stakeholders.”
Response 2: Thank you for pointing this out. According to your comment, we have reviewed the possible effect of seed treatments on the beneficial endophytes, by adding the paragraph in pp. 15 - 6.2 Seed sanitation methods and procedures - new lines 663-673 to emphasize this part: “In addition, seed treatments applied during a sanitation procedure (e.g. thermal treatments, application of chemicals) may concurrently suppress the vitality of seed-associated beneficial endophytes, which have a pivotal role in early seedling growth and establishment [22]. These seed endophytes serve as an important link between the microbiome vertical transmission to the next seedling generation as well: therefore, it is important to assess the consequences of seed treatment practices on the whole seed microbiota [113]. Little is known about the unintended adverse effects of seed treatments on non-target beneficial endophytes that may attenuate the net benefit of these practices. Therefore, the mechanisms behind seed treatment-endophyte-seedling growth interactions, which may have a role in the development of sustainable disease control strategies, should be deeply investigated [114].”
Response 3: Thank you for pointing this out. According to your comment, we have reviewed the role of resistant/tolerant tomato and pepper varieties to bacterial spot, bacterial speck and bacterial canker as a tool in the IPM, by adding the paragraph in pp. 13 - 6. Seed treatments - new lines 550-562 to explain this part: “However, another key role in the management of bacterial diseases is played by tolerant/resistant tomato and pepper varieties. Host resistance can limit disease severity, the spread of bacterial secondary inocula in the field throughout the crop season and, therefore, the use of bactericides [92]. Commercial varieties of tomato with moderate tolerance against Cmm, moderate resistance (IR) against Xanthomonads (i.e. Xee, Xv, Xep), complete resistance (HR) against Pst (i.e. race 0 and race 1) and of pepper (Capsicum annuum L.) with resistance to bacterial spot, are currently available on the market [93, 94]. However, the continuous efforts to identify introgressions of resistance is challenging, since the development of Cmm, Pst and Xanthomonads disease-resistant cultivars stimulates the emergence of new races and species of these pathogens. Moreover, the frequent negative correlation between fruit quality and disease resistance has made the introgression of resistance even more challenging [95].”
Response 4: The whole manuscript has been now revised and language improved by an English native speaker.
Author Response File: Author Response.pdf
Reviewer 3 Report
Comments and Suggestions for AuthorsThe submitted review article focuses on serious problematics of global outspreading of seed-borne phytopathogenic bacteria under modern world-wide seed trade and international specialization of tomato and pepper seed material manufacturers and suppliers. The review highlights current knowledges and new research aspects of the considered plant pathogens in view of biology of seed endophytes, characterizes the key groups of bacterial pathogens infecting tomatoes and pepper, and the ways of the crops seed colonization by these bacteria. Besides, the article elucidates in details the methodologies of identification of the phytopathogenic bacteria in tomato and pepper seeds as well as current approaches for the seed treatment and their potential and weaknesses on the practical side.
Undoubtedly, the presented review article is highly relevant both in basic and, especially, application aspects in view of sustainable development, food security, environmentally friendly agriculture etc. The article is qualified, well-organized and clearly written, informatively and comprehensively elaborating on the main subject. Therefore, the article is quite worthy to be published in the Journal. As minor comments, I would like to recommend that the authors, for greater illustrations, present small schemes for a number of sections, such as section 4 (ways of colonization) and section 5 (methods of detection of plant pathogens in seeds). Moreover, the Table 1 could be optimized by size through partial reduction of excessive (or insubstantial) text and digital values in some columns (for example, “Operating conditions” and “Efficacy and additional notes”) as well as constrict edgewise the column “References”.
Few other minor comments are listed below.
L. 31: “crucial and critical” – The difference between the terms is unclear for the context.
L. 34: “FAO” – please, write completely for first mention. The analogous remark belongs to other such cases.
L. 91: The title of the Section 2 (“…recruitment and dynamics”) doesn’t look very clearly in terms of the general section content.
L. 141: “germs” – Hereinafter, use of this term as synonym of “bacteria” should be limited and not be repeated often as is the case in the article. In microbiological view, is not quite correct.
l. 250-251: The Section 4 title should not contain the name of the bacterial species as an abbreviation. The section itself partly repeat some places (belonging to infection way by a pathogen) of previous one.
l. 396: “EPPO” – disclose for first mention in the text.
l. 579: “need and necessity” - What did the authors mean by using these two related words?
l. 772: “mBCA” – disclose.
l. 802: “research and investigations” – Probably, the second word is unnecessary here.
Author Response
Dear Reviewer 3,
Thank you very much for taking the time to review this manuscript. Please find the detailed responses below and the corresponding revisions/corrections highlighted/in track changes in the re-submitted files.
Response 1: Thank you for pointing this out. We agree with this comment. Therefore, we have presented a scheme for Sections 4 and 5, respectively. These schemes were added in Section 4 as Figure 2 [“Graphical representation of disease cycle for seed-borne bacterial canker (C), bacterial speck (P) and bacterial spot (X) diseases on tomato.”; pp. 8, line 343] and in Section 5 as Figure 3 [“Figure 3. Scheme for the detection and identification of Clavibacter michiganensis subsp. michiganensis, Clavibacter capsici, Xanthomonas euvesicatoria pv. euvesicatoria, X. e. pv. perforans, X. hortorum pv. gardneri, X. vesicatoria and Pseudomonas syringae pv. tomato through direct isolation: after sample processing, plating seed extract on specific semi-selective media, sub-culturing pathogen-like colonies on nutritive media, identification of the axenic colonies through molecular, serological and/or biochemical methods.“; pp. 12, line 516].
Response 2: Thank you for pointing this out. According to your comment, we have optimized by size through partial reduction of text and digital values in the columns “Operating conditions” and “Efficacy and additional notes”. We have also constricted edgewise the column “References” (pp. 29, Table 1).
Response 3: According to reviewer’s comments, please find below our revisions point-by-point:
Reviewer 3 - L. 31: “crucial and critical” – The difference between the terms is unclear for the context. Authors: Response to Reviewer: according to the Reviewer comment, to be clearer for the context, the words “critical and crucial were replaced with “important” [line 31].
Reviewer 3 - L. 34: “FAO” – please, write completely for first mention. The analogous remark belongs to other such cases Authors: according to the Reviewer comment, the following acronyms were written completely for first mention:
1. Food and Agriculture Organization of the United Nations (FAO) [line 34];
2. International Standards for Phytosanitary Measures (ISPM) [lines 39-40];
3. National Seed Health System (NSHS) [lines 403];
4. Random Amplification of Polymorphic DNA (RAPD) [lines 502-503];
5. Good Seed and Plant Practices (GSPP) [line 531];
6. Generally Recognised as Safe (GRAS) [line 839];
7. microbial biological control agent (mBCA) [line 776]
Reviewer 3 - L. 91: The title of the Section 2 (“…recruitment and dynamics”) doesn’t look very clearly in terms of the general section content Authors: According to this comment, we have changed “dynamics” with “role” to be clearer [line 116]. This because if “recruitment is related to the part of this section of the recruitment of the microbial endophytes, “role” is related to the initial role that these communities play during the early stages of seed germination and plant development (i.e. initial inoculum).
Reviewer 3 - L. 141: “germs” – Hereinafter, use of this term as synonym of “bacteria” should be limited and not be repeated often as is the case in the article. In microbiological view, is not quite correct. Authors: Response to Reviewer 3: according to the Reviewer comment, we have replaced 8 out of 9 words “germs” with bacteria along the manuscript. Please find below the changes in details:
1. L. 167: “germs” was replaced with “bacteria”;
2. L. 234: “germs can evade the plant as bacterial exudates” was replaced with “bacteria can evade the plant as exudates “;
3. L. 262: “germs” was replaced with “Xanthomonads”
4. L. 304: “germs” was maintained;
5. L. 363: “germs” was deleted;
6. L. 367: “germs” was replaced with “bacteria”;
7. L. 444: “germs” was replaced with “cells”;
8. L. 510: “germs was replaced with “phytopathogenic bacteria”
9. L. 701: “germs” was replaced with bacteria”.
Reviewer 3 - L. 250-251: The Section 4 title should not contain the name of the bacterial species as an abbreviation. The section itself partly repeats some places (belonging to infection way by a pathogen) of previous one. Authors: according to Reviewer’s comments, Section 4 was modified as follow:
1. Pst has been replaced with Pseudomonas syringae pv. tomato [lines 280-281];
2. Lines 190-196 of Section 3 were moved to Section 4 to avoid repetition [new lines 308-314];
3. Lines: 282-284, Lines: 299-304, Lines 3014-317, Lines: 325-331. were deleted because partly repeat places of previous Section 3.
Reviewer 3 - L. 396: “EPPO” – disclose for first mention in the text. Authors: EPPO was disclosed for the first mention in lines 187-188: “….A2 list of quarantine organisms by the European and Mediterranean Plant Protection Organization (EPPO) [31]. Similarly………”
Reviewer 3 - L. 579: “need and necessity” - What did the authors mean by using these two related words? Authors: The authors have written “need” with the meaning of requirement to control seed transmitted diseases. The word “necessity” was used to highlight the constraint to supply healthy seed for avoiding the spread of seedborne pathogens and the yield losses to farmers. To be clearer, “need and necessity” were replaced by “need”. [Line 652].
Reviewer 3 - L. 772: “mBCA” – disclose. Authors: according to the Reviewer comment, the acronym mBCS was written completely for first mention: “microbial biological control agent (mBCA)” [lines 860-861]
Reviewer 3 - L. 802: “research and investigations” – Probably, the second word is unnecessary here. Authors: according to the Reviewer comment, ““research and investigations” were replaced with “research” [Line 891].
Author Response File: Author Response.pdf
Round 2
Reviewer 2 Report
Comments and Suggestions for AuthorsThe authors have addressed my concerns and I recommend accepting their manuscript (Tomato and pepper seeds as pathways for the dissemination of phytopathogenic bacteria: a constant challenge for the seed industry and the sustainability of crop production) for publication in SUSTAINABILITY.
