TRANSGENIC PLANTS THAT EXPRESS GENES INCLUDING THE 3' UNTRANSLATED REGION OF THE TURNIP YELLOW MOSAIC-VIRUS (TYMV) GENOME ARE PARTIALLY PROTECTED AGAINST TYMV INFECTION

In order to evaluate new possibilities for protecting plants against v irus infection by interference with viral replication, two chimeric ge nes were constructed in which the (+) strand 3'-terminal 100 nucleotid es (nt) of the noncoding region of the turnip yellow mosaic virus (TYM V) genome were placed downstream from the sense or antisense cat codin g region. The two chimeric genes were then introduced into the genome of rapeseed (Brassica napus) using an Agrobacterium rhizogenes vector system. Plants expressing high levels of either chimeric gene showed p artial protection against infection by TYMV RNA or virions. One intere sting feature of the protection is that a proportion of the inoculated transgenic plants does not become infected. Protection was overcome w hen the inoculum concentration was increased. RNA complementary to the initial transcript was detected after infection.