Sm gene confers tolerance to ToBRFV in tomato

Abstract

Tomato brown rugose fruit virus (ToBRFV) infection significantly reduces plant vigor, fruit size, and quality, and in the long term affects international seed trade. Several genes have been reported to restrict the systemic spread of ToBRFV in tomato, thereby conferring partial tolerance. We hypothesized that the SmRR gene, an incomplete dominant resistant gene against Stemphylium sp. in tomato, may also contribute to tolerance against ToBRFV infection. To test this, tomato varieties containing the SmRR or Smrr genes were mechanically inoculated with ToBRFV. Symptom severity on leaves was recorded at one, two, and three weeks post-inoculation using a standardized disease rating scale, and viral presence was confirmed by RT-PCR. Results showed that the Smrr (susceptible) variety exhibited the highest disease severity (maximum score= 3), while the SmRR variety had a lower average severity score (1.5) and no visible fruit symptoms, indicating tolerance. Future studies should employ functional assays, such as gene knockdown or overexpression, to validate the role of SmRR in ToBRFV tolerance.

Keywords

• ToBRFV
• SmRR
• Stemphylium sp.
• Tomato
• Virus

Project Number

1919B012406656

References

1. Ashkenazi V, Rotem Y, Ecker R, Nashilevitz S, Barom N (2020) Resistance in plants of Solanum lycopersicum to the tobamovirus tomato brown rugose fruit virus. Patentscope. doi:patentscope.wipo.int/search/en/detail.jsf?docId=WO2020249798andtab=SEARCHREPORT.
2. Bashi E, Pilowsky M, Rotem J (1973) Resistance in tomatoes to Stem- phylium floridanum and Stemphylium botryosum f. sp. lycopersici. Phytopathology 63: 1542-1544.
3. Cayak HN, Fidan H (2024) Multiplex PCR methods for simultaneous detection of tomato brown rugose fruit virus, tomato spotted wilt virus and pepino mosaic virus. Journal of Phytopathology 172(3): e13327. doi: 10.1111/jph.13327.
4. Cui Y, Jiang J, Yang H, Zhao T, Xu X, Li J (2018) Virus-induced gene silencing (VIGS) of the NBS-LRR gene SLNLC1 compromises Sm-mediated disease resistance to Stemphylium lycopersici in tomato. Biochemical and Biophysical Research Communications 503(3): 1524-1529. doi:org/10.1016/j.bbrc.2018.07.074.
5. Doyle J (1991) DNA protocols for Plants. In Molecular Taxonomy in Plants Berlin Heidelberg: Springer Berlin Heidelberg, pp. 283-293.
6. Kabas A, Fidan H, Kucukaydin H, Atan HN (2022) Screening of wild tomato species and interspecific hybrids for resistance/tolerance to Tomato brown rugose fruit virus (ToBRFV). Chilean Journal of Agricultural Research 82(1): 189-196. doi:org/10.4067/S0718-58392022000100189.
7. Kubota K, Takeyama S, Matsushita Y, Ishibashi K (2024) Isolation of spontaneous mutants of tomato brown rugose fruit virus that efficiently infect Tm-1 homozygote tomato plants. Journal of General Plant Pathology 90(4): 187-195. doi:org/10.1007/s10327-024-01176-2.
8. Li X, Zhang H, Tian L, Huang L, Liu S, Li D, Song F (2015) Tomato SLRbohB, a member of the NADPH oxidase family, is required for disease resistance against Botrytis cinerea and tolerance to drought stress. Frontiers in Plant Science 6: 1-14. doi:org/10.3389/fpls.2015.00463.

9. Rochsar E, Torgeman S, Bandel K, Koren A, Klap C, Dombrovsky A, Zamir D (2025) Tissue-specific resistance and susceptibility to the tomato brown rugose fruit virus (ToBRFV) conferred by Solanum pennellii loci. BMC Plant Biology 25(1). doi:org/10.1186/s12870-024-05989-3.
10. Salem N, Mansour A, Ciuffo M, Falk BW, Turina M (2016) A new tobamovirus infecting tomato crops in Jordan. Archives of Virology 161(2): 503-506. doi:10.1007/s00705-015-2677-7.
11. Salem NM, Sulaiman A, Samarah N, Turina M,Vallino M (2022) Localization and Mechanical Transmission of Tomato Brown Rugose Fruit Virus in Tomato Seeds. Plant Disease 106(1). doi:10.1094/PDIS-11-20-2413-RE.
12. Salem NM, Jewehan A, Aranda MA, Fox A (2023) Tomato Brown Rugose Fruit Virus Pandemic. In Annual Review of Phytopathology 61. doi:org/10.1146/annurev-phyto-021622-120703.
13. Su X, Zhu G, Huang Z, Wang X, Guo Y, Li B, Du Y, Yang W, Gao J (2019) Fine mapping and molecular marker development of the Sm gene conferring resistance to gray leaf spot (Stemphylium spp.) in tomato. Theoretical and Applied Genetics 132(4): 871-882. doi: 10.1007/s00122-018-3242-z.
14. Yilmaz S, Batuman O (2023) Co-Infection of Tomato Brown Rugose Fruit Virus and Pepino Mosaic Virus in Grocery Tomatoes in South Florida: Prevalence and Genomic Diversity. Viruses 15(12). doi: 10.3390/v15122305.
15. Zhou J, Gilliard A, Tung J, Dinesh-Kumar SP, Whitham SA, Baker B, Ling KS (2025) The N gene protects tomato plants from tomato brown rugose fruit virus infection. Plant Biotechnology Journal 23(10): 4339-4349. doi: org/10.1111/pbi.70237.
16. Zinger A, Lapidot M, Harel A, Doron-Faigenboim A, Gelbart D, Levin I (2021) Identification and Mapping of Tomato Genome Loci Controlling Tolerance and Resistance to Tomato Brown Rugose Fruit Virus. Plants 10(1): 179. doi:org/10.3390/plants10010179.