Woody Canker and Shoot Blight Caused by Botryosphaeriaceae and Diaporthaceae on Mango and Litchi in Italy

Round 1

Reviewer 1 Report

please see the comments in the attached pdf

Comments for author File: Comments.pdf

Author Response

Thank you for the comments and suggestions. The authors done all requests as suggested. Please see the manuscript.

Major revision:

Q Authors performed field survey mango and litchi plants, but with no data for this part, only the disease symptoms were displayed here. The field survey data should contain the location, area surveyed, as well as the disease severity index. Also, a rating scale should set based on this disease development. From the field survey, authors can convey the information that how serious this disease is, how large this disease developed in area surveyed, and this disease is important or not for these two crops.

A Thank you for the comment, you are right. This information is missing. We added some data about location and orchards surveyed. Field survey showed a quite difference of disease incidence among the cultivars. However, the symptoms severity was not evaluated. Please see the manuscript. Lines 178-185.

 

Q For pathogenicity tests, authors obtained 54 isolates totally, did authors perform the inoculation test for all of them? Are there differences between the disease severities for all isolates and species? How many replicates for each isolate were tested? Among the six fungi species, which one is the predominant one? In addition, the rating scale should be used to score the disease development. It is of importance to reveal the most serious fungi species responsible for this disease. Authors should describe these in the results and methods section.

A Thank you for the comment, you are right. This information is missing. The authors performed the inoculation test for all fungal species found for a first time, using one representative isolate for each species. For each isolate, six potted plants of mango and/or litchi were used for the inoculation test and these were wounded in 3 different points of stem. Overall, three replicates with two plants each and 3 different inoculation points for each plant.

The aim of our study was determined the fungal species associated with these symptoms and only the pathogenicity of the isolate/species was evaluated. We didn’t determine the symptom severity. However, the results of tests showed a little difference among the different fungal isolates. All isolates induced similar lesions on inoculated host species and no difference in length of the resulting lesions was observed after 1 month. Otherwise, after 3 months the infection resulted in apical dieback of the mango plants when inoculated with D. baccae isolate. The other isolates, instead, killed the plants after more of 6 months. Please see the manuscript. Lines 163-166; 294-299.

Among the six fungal species from mango, Neofusicoccum parvum (already reported in Italy) was the predominant species. Line 344.

Minor revision:

The authors done all requests as suggested. Please see the manuscript.

Reviewer 2 Report

Aiello et al. 2022, report the discovery of plant pathogens on mango and litchi (lychee) production trees in central and southern Italy, and Sicily which represent an emerging market in Italy for locally grown tropical fruits.  The authors used a combination of culturing, reinfection and isolation to confirm Koch’s postulates and causal agent determination was accomplished through morphological measurements of fruiting bodies in culture and genotyping (with 3 different genes).  Phylogenetic analyses were used to locate isolate genotypes among those species and closely related fungal taxa hypothesized to be part of the same clade. 

The authors did a good job of writing and presenting their approach to identify the causal agents of disease on Italy-grown mango and litchi trees.  I agreed with their methods and found them to be robust and that their data/analyses supported their identifications.

I have just a few minor comments and suggestions that if addressed by the authors could improve the manuscript.

Overall, the manuscript was well written.  However, there were paragraphs in the Introduction that need attention due to confusing and unclear writing.  Below, I have called the authors attention to these few paragraphs. 

Introduction

Lines 60-75.  These two paragraphs, the rest of the Introduction is well-written.

Other editorial suggestions

Figure 4 legend is incomplete.

Line 55: change “case” to “cases”

 

Methodological questions

Section 2.1

The authors report on surveys for diseased plants. Did the authors keep track of the numbers of plants that were diseased/not-diseased by location and year?  If so, this is important baseline abundance information that has value and could be shared in this manuscript.  This is not necessary for publication but it would be a nice additional piece of information.

Section 2.2

Did the authors inspect the infected stems of mango and litchi for fruiting bodies to determine if the pycnidia characteristics were also those observed in the cultures?  This is not necessary, but it there are fruiting body measurements from the infected plants that would be a nice piece of information to include.

Section 2.4

I assume that the sequences for the phylogenetic analysis were concatenated, but maybe this is not the case.  It would be helpful if the authors indicated whether the 3 genes were used to form a concatenated sequence.  If the authors did not concatenate the sequences, please describe the method used to form a tree from the 3 different genes (presumably a concensus or consensus-like approach).  I don’t think there is enough information for someone to repeat the phylogenetic analysis as the manuscript is presently written.

Author Response

Thank you for the comments and suggestions. The authors done all requests as suggested. Please see throught the manuscript.

Methodological questions

Section 2.1

Q The authors report on surveys for diseased plants. Did the authors keep track of the numbers of plants that were diseased/not-diseased by location and year?  If so, this is important baseline abundance information that has value and could be shared in this manuscript.  This is not necessary for publication but it would be a nice additional piece of information.

A Thanks for the comment, you are right. This information is missing. Symptomatic plants of mango (cvs. Kent, Keitt, Sensation, Osteen and Kensington Pride) were observed in 7 orchards (from Giarre and Fiumefreddo municipalities, Catania province) while litchi infections were observed only in one orchard in Caronia municipality (Messina province). On mango plants disease incidence (DI) varied approximately from 3% to 18% according to plant cultivar and orchard investigated, with the lowest values for Kensington Pride and the higher values for Osteen. On litchi, the DI was approximately 30% on Way Chee and 1% on Kwai Mai Pink. Please see the manuscript. Lines 180-187.

Section 2.2

Q Did the authors inspect the infected stems of mango and litchi for fruiting bodies to determine if the pycnidia characteristics were also those observed in the cultures?  This is not necessary, but it there are fruiting body measurements from the infected plants that would be a nice piece of information to include.

A Sometimes we found fruiting bodies on the infected stems of mango and litchi but we didn’t measure these from the infected plants.

Section 2.4

Q I assume that the sequences for the phylogenetic analysis were concatenated, but maybe this is not the case.  It would be helpful if the authors indicated whether the 3 genes were used to form a concatenated sequence.  If the authors did not concatenate the sequences, please describe the method used to form a tree from the 3 different genes (presumably a concensus or consensus-like approach).  I don’t think there is enough information for someone to repeat the phylogenetic analysis as the manuscript is presently written.

A Thanks for noticing this. We have considered as obvious the use of concatenated genes, but we erroneously did not specify it in the text. This has been fixed. See the manuscript. Lines 146-148.

Reviewer 3 Report

This manuscript is acceptable in Horticulturae in Plant Pathology and Disease Management section. In general, this is a well-written manuscript summarizing interesting and important research but requires minor editorial changes.

This study is well conducted using morphological and molecular methods of pathogen detection and identification.

Pathogenicity tests were done and Koch’s postulates were fulfilled with six species.

Therefore it should be accepted for publication after minor improvements.

line 19: ’ Catania and Messina provinces’ should be deleted (unnecessary information here)

line 22: replace ’portion’ with ’part’

line 45: this sentence should be rewritten

line 72-73: replace ’orchard’ with ’many orchards’ or ’some orchards’

line 112: replace ’RNA operon’ with ’DNA’

line 136-137: rephrase this sentence

Since morphological observations of the species were also made, photos of the cultures and conidia should be included in the manuscript.

Author Response

Thank you for the comments and suggestions. The authors done all requests as suggested. Please see the manuscript.

Q Since morphological observations of the species were also made, photos of the cultures and conidia should be included in the manuscript.

A You are right. We evaluated the size and shape of conidia and the characteristics of colonies and pycnidia/conidiomata. Measurements of conidia were made for one representative isolate of each species recovered but we don’t have good photographs of these structures for all species found, so we prefer not to insert them. Then, I changed the phrase. Line 109-115.

 

Round 2

Reviewer 1 Report

I am fine with the present version.