Specificity of Resistance and Tolerance to Cucumber Vein Yellowing Virus in Melon Accessions and Resistance Breaking with a Single Mutation in VPg

Cucumber vein yellowing virus (CVYV) is an emerging virus on cucurbits in the Mediterranean Basin, against which few resistance sources are available, particularly in melon. The melon accession PI 164323 displays complete resistance to isolate CVYV-Esp, and accession HSD 2458 presents a tolerance, i...

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Bibliographic Details
Published in:Phytopathology 2022-05, Vol.112 (5), p.1185-1191
Main Authors: Desbiez, Cécile, Domingo-Calap, Maria Luisa, Pitrat, Michel, Wipf-Scheibel, Catherine, Girardot, Grégory, Ferriol, Inmaculada, Lopez-Moya, Juan José, Lecoq, Hervé
Format: Article
Language:English
Subjects:
Cucumis sativus
Cucurbitaceae - genetics
Mutation
Plant Breeding
Plant Diseases
Potyviridae
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Summary:Cucumber vein yellowing virus (CVYV) is an emerging virus on cucurbits in the Mediterranean Basin, against which few resistance sources are available, particularly in melon. The melon accession PI 164323 displays complete resistance to isolate CVYV-Esp, and accession HSD 2458 presents a tolerance, i.e., very mild symptoms despite virus accumulation in inoculated plants. The resistance is controlled by a dominant allele - , while the tolerance is controlled by a recessive allele - , independent from - . Before introducing the resistance or tolerance in commercial cultivars through a long breeding process, it is important to estimate their specificity and durability. Upon inoculation with eight molecularly diverse CVYV isolates, the resistance was found to be isolate-specific because many CVYV isolates induced necrosis on PI 164323, whereas the tolerance presented a broader range. A resistance-breaking isolate inducing severe mosaic on PI 164323 was obtained. This isolate differed from the parental strain by a single amino acid change in the VPg coding region. An infectious CVYV cDNA clone was obtained, and the effect of the mutation in the VPg cistron on resistance to PI 164323 was confirmed by reverse genetics. This represents the first determinant for resistance-breaking in an ipomovirus. Our results indicate that the use of the - allele alone will not provide durable resistance to CVYV and that, if used in the field, it should be combined with other control methods such as cultural practices and pyramiding of resistance genes to achieve long-lasting resistance against CVYV.
ISSN:0031-949X
1943-7684
DOI:10.1094/PHYTO-06-21-0263-R