THE COAT PROTEIN IS REQUIRED FOR THE ELICITATION OF THE CAPSICUM L(2)GENE-MEDIATED RESISTANCE AGAINST THE TOBAMOVIRUSES

In Capsicum, the resistance against tobamoviruses conferred by the L(2 ) gene is effective against all but one of the known tobamoviruses. Pe pper mild mottle virus (PMMoV) is the only virus which escapes its act ion, To identify the viral factors affecting induction of the hypersen sitive reaction (HR) mediated by the Capsicum spp. L(2) resistance gen e, we have constructed chimeric viral genomes between paprika mild mot tle virus (PaMMV) (a virus able to induce the HR) and PMMoV. A hybrid virus with the PaMMV coat protein gene substituted in the PMMoV-S sequ ences was able to elicit the HR in Capsicum frutescens (L(2)L(2)) plan ts. These data indicate that the sequences that affect induction of th e HR mediated by the L(2) resistance gene reside in the coat protein g ene. Furthermore, a mutant that codes for a truncated coat protein was able to systemically spread in these plants. Thus, the elicitation of the host response requires the coat protein and not the RNA.