Apples and pears: two closely related species with differences in scab nonhost resistance
Phenotypic and transcriptomic analyses reveal major differences between apple and pear scab nonhost resistance
Recommendation: posted 25 November 2022, validated 25 November 2022
Pootakham, W. (2022) Apples and pears: two closely related species with differences in scab nonhost resistance. Peer Community in Genomics, 100025. https://doi.org/10.24072/pci.genomics.100025
Nonhost resistance is a common form of disease resistance exhibited by plants against microorganisms that are pathogenic to other plant species . Apples and pears are two closely related species belonging to Rosaceae family, both affected by scab disease caused by fungal pathogens in the Venturia genus. These pathogens appear to be highly host-specific. While apples are nonhosts for Venturia pyrina, pears are nonhosts for Venturia inaequalis. To date, the molecular bases of scab nonhost resistance in apple and pear have not been elucidated.
This preprint by Vergne, et al (2022)  analyzed nonhost resistance symptoms in apple/V. pyrina and pear/V. inaequalis interactions as well as their transcriptomic responses. Interestingly, the author demonstrated that the nonhost apple/V. pyrina interaction was almost symptomless while hypersensitive reactions were observed for pear/V. inaequalis interaction. The transcriptomic analyses also revealed a number of differentially expressed genes (DEGs) that corresponded to the severity of the interactions, with very few DEGs observed during the apple/V. pyrina interaction and a much higher number of DEGs during the pear/V. inaequalis interaction.
This type of reciprocal host-pathogen interaction study is valuable in gaining new insights into how plants interact with microorganisms that are potential pathogens in related species. A few processes appeared to be involved in the pear resistance against the nonhost pathogen V. inaequalis at the transcriptomic level, such as stomata closure, modification of cell wall and production of secondary metabolites as well as phenylpropanoids. Based on the transcriptomics changes during the nonhost interaction, the author compared the responses to those of host-pathogen interactions and revealed some interesting findings. They proposed a series of cascading effects in pear induced by the presence of V. inaequalis, which I believe helps shed some light on the basic mechanism for nonhost resistance.
I am recommending this study because it provides valuable information that will strengthen our understanding of nonhost resistance in the Rosaceae family and other plant species. The knowledge gained here may be applied to genetically engineer plants for a broader resistance against a number of pathogens in the future.
1. Senthil-Kumar M, Mysore KS (2013) Nonhost Resistance Against Bacterial Pathogens: Retrospectives and Prospects. Annual Review of Phytopathology, 51, 407–427. https://doi.org/10.1146/annurev-phyto-082712-102319
2. Vergne E, Chevreau E, Ravon E, Gaillard S, Pelletier S, Bahut M, Perchepied L (2022) Phenotypic and transcriptomic analyses reveal major differences between apple and pear scab nonhost resistance. bioRxiv, 2021.06.01.446506, ver. 4 peer-reviewed and recommended by Peer Community in Genomics. https://doi.org/10.1101/2021.06.01.446506
The recommender in charge of the evaluation of the article and the reviewers declared that they have no conflict of interest (as defined in the code of conduct of PCI) with the authors or with the content of the article. The authors declared that they comply with the PCI rule of having no financial conflicts of interest in relation to the content of the article.
This project was funded by the Synthé-Poir-Pom project (Angers University) and by the TIFON project (INRAE, department BAP).
Reviewed by anonymous reviewer 1, 05 Nov 2022
Evaluation round #1
DOI or URL of the preprint: https://doi.org/10.1101/2021.06.01.446506
Version of the preprint: 2
Author's Reply, 26 Oct 2022
Decision by Wirulda Pootakham, posted 09 Sep 2022
The reviewers have looked at the manuscript, and two of them provided extensive and valuable feedbacks. Please take a look at their comments below and revise your manuscript accordingly. Please pay special attention to the comments on the enrichment test as I also think it is important to carry out such test. In addition, please make sure that the hypothesis or anything that is not supported by the evidence provided in this study is written in a way that conveys the "hypothetical" nature of it (the language used should not be too ascertain). Please let us know if you require an extension on the revision of the paper.