Abstract
Tomato brown rugose fruit virus (ToBRFV) was identified in Israel during October 2014 in tomato plants (Solanum lycopersicum). These plants, carrying the durable resistance gene against tomato mosaic virus, Tm-22, displayed severe disease symptoms and losses to fruit yield and quality. These plants were found infected with a tobamovirus similar to that discovered earlier in Jordan. This study was designed to screen and identify tomato genotypes resistant or tolerant to ToBRFV. The identified resistance and tolerance traits were further characterized virologically and genetically. Finally, DNA markers linked to genes controlling these traits were developed as tools to expedite resistance breeding. To achieve these objectives, 160 genotypes were screened, resulting in the identification of an unexpectedly high number of tolerant genotypes and a single genotype resistant to the virus. A selected tolerant genotype and the resistant genotype were further analyzed. Analysis of genetic inheritance revealed that a single recessive gene controls tolerance whereas at least two genes control resistance. Allelic test between the tolerant and the resistant genotype revealed that these two genotypes share a locus controlling tolerance, mapped to chromosome 11. This locus displayed a strong association with the tolerance trait, explaining nearly 91% of its variation in segregating populations. This same locus displayed a statistically significant association with symptom levels in segregating populations based on the resistant genotype. However, in these populations, the locus was able to explain only ~41% of the variation in symptom levels, confirming that additional loci are involved in the genetic control of the resistance trait in this genotype. A locus on chromosome 2, at the region of the Tm-1 gene, was finally found to interact with the locus discovered on chromosome 11 to control resistance.
Highlights
Viral diseases cause serious damage to plants by significantly reducing their yield and fruit quality
Tomato brown rugose fruit virus (ToBRFV) Overcomes Genetic Resistance to tomato mosaic virus (ToMV) in Tomato In Israel, ToBRFV was initially identified in commercial ToMV-resistant tomato plants carrying the Tm-22 gene [17]
The ToMV-resistant genotypes displayed very high average disease severity index (DSI) and viral levels when infected with ToBRFV, very much like the ToMV-susceptible control
Summary
Viral diseases cause serious damage to plants by significantly reducing their yield and fruit quality. Plant viruses are mostly spread by insects, such as aphids, thrips and whiteflies, and are one of the reasons why in many locations production has shifted from open field to protected environments [1]. The worldwide yield losses that can be ascribed to plant viruses are estimated to be more than 30 billion US$ annually [2]. One of the most devastating viruses infecting plants of the Solanaceae family and tomatoes in particular, are tobamoviruses. The two best-known viruses of this genus are tobacco mosaic virus (TMV) and tomato mosaic virus (ToMV) [4,5]. Unlike other viruses transmitted by vectors, Tobamoviruses are mechanically transmitted and are considered most persistent in terms of their ability to survive outside plant cells and in dead plant tissues [6]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
