Different Haplotypes Encode the Same Protein for Independent Sources of Zucchini Yellow Mosaic Virus Resistance in Cucumber

Cucumber ( Cucumis sativus ) production is negatively affected by Zucchini yellow mosaic virus (ZYMV). Three sources of ZYMV resistance have been commercially deployed and all three resistances are conditioned by a single recessive gene. A vacuolar protein sorting–associated protein 4-like (VPS4-like) gene has been proposed as a candidate for ZYMV resistance from cucumber line A192-18. We analyzed the genomic region across the VPS4-like gene for three independent sources of ZYMV resistance in cucumber (A192-18, Dina-1, and TMG-1) and identified three haplotypes across the coding region and considerable variation in the introns. However, the haplotypes in the coding regions of the VPS4-like gene of A192-18, Dina-1, and TMG-1 encode the same protein sequence, revealing the genetic uniformity for ZYMV resistance from diverse germplasm sources.