Microarray Analysis Shows That Recessive Resistance to Watermelon mosaic virus in Melon Is Associated with the Induction of Defense Response Genes

[EN] Resistance to Watermelon mosaic virus (WMV) in melon (Cucumis melo L.) accession TGR-1551 is characterized by a significant reduction in virus titer, and is inherited as a recessive, loss-of-susceptibility allele. We measured virus RNA accumulation in TGR-1551 plants and a susceptible control ('Tendral') by real-time quantitative polymerase chain reaction, and also profiled the expression of 17,443 unigenes represented on a melon microarray over a 15-day time course. The virus accumulated to higher levels in cotyledons of the resistant variety up to 9 days postinoculation (dpi) but, thereafter, levels increased in the susceptible variety while those in the resistant variety declined. Microarray experiments looking at the early response to infection (1 and 3 dpi), as well as responses after 7 and 15 dpi, revealed more profound transcriptomic changes in resistant plants than susceptible ones. The gene expression profiles revealed deep and extensive transcriptome remodeling in TGR-1551 plants, often involving genes with pathogen response functions. Overall, our data suggested that resistance to WMV in TGR-1551 melon plants is associated with a defense response, which contrasts with the recessive nature of the resistance trait.This work was supported by grant AGL2009-07552/AGR from Ministerio de Ciencia e Innovacion (Spain). We thank E. Moriones and M. Gomez-Guillamon for providing materials for this work, M. C. Montesinos and B. Gosalvez for their technical assistance and R. M. Twyman for editorial assistance.Gonzalez-Ibeas, D.; Cañizares Sales, J.; Aranda, MA. (2012). Microarray Analysis Shows That Recessive Resistance to Watermelon mosaic virus in Melon Is Associated with the Induction of Defense Response Genes. Molecular Plant-Microbe Interactions. 25(1):107-118. doi:10.1094/MPMI-07-11-0193S10711825