RELATIONSHIP BETWEEN TRANSCRIPT PRODUCTION AND VIRUS-RESISTANCE IN TRANSGENIC TOBACCO EXPRESSING THE POTATO LEAFROLL VIRUS COAT PROTEIN GENE

The coat protein (CP) gene of potato leafroll luteovirus (PLRV) was in serted into tobacco (Nicotiana tabacum ) using disarmed Agrobacterium tumefaciens (LBA4404) containing a binary expression vector. PLRV CP g ene transcript was detected in transgenic plants but its abundance dif fered between transformed lines. CP was not detected in virus-free tra nsgenic plants. The segregation of kanamycin resistance in S1 seedling progenies (obtained by selfing transformed plants) indicated that mul tiple (up to five) integration events involving vector T-DNA had occur red in most transformants. However, the amount of detectable CP transc ript was not related to the neomycin phosphotransferase II gene copy n umber. Multiplication of PLRV in mature transgenic plants was diminish ed by up to 6-fold, the greatest diminution was in those transformed l ines in which most CP gene transcript was detected. However, S1 progen y seedlings of transgenic plants were no more resistant to infection, following inoculation with viruliferous aphids, than seedlings of non- transformed control plants.