A SEARCH FOR RESISTANCE TO CUCUMBER MOSAIC VIRUS IN THE GENUS LYCOPERSICON
J. Abad, G. Anastasio, A. Fraile, F. García-Arenal
A search for resistance to Cucumber mosaic virus (CMV) within the genus Lycopersicon was made. Resistance to CMV isolates from eastern Spain were found in accessions of the species L. hirsutum (2 accessions), L. chmielewskii (1 accession), L. pimpinellifolium (1 accession) and L. esculentum (3 accessions). When these accessions were assayed against Fny-CMV, a strain more severe than the Spanish field isolates tested before, only L. chmielewskii CHM-47 was resistant; L. hirsutum HIR-25 showed mild symptoms and some plants were not infected. All the other accessions were susceptible, indicating that their resistance was strainspecific. Tolerance to the systemic necrosis induced by Ix-satRNA was not found in nine assayed accessions of L. hirsutum, L. peruvianum, L. pimpinellifolium and L. esculentum. In resistant plants of L. chmielewskii CHM -47 and L. hirsutum HIR-25 no accumulation of either Fny-CMV or LS-CMV was detected by ELISA in inoculated or upper leaves. Nevertheless, when scions of these plants were graft-inoculated with Fny-CMV they became infected. This indicates that the resistance factors in these accessions do not interfere with replication or cell-to-cell movement but, possibly with earlier stages of virus infection.