MOVEMENT OF A BARLEY STRIPE MOSAIC-VIRUS CHIMERA WITH A TOBACCO MOSAIC-VIRUS MOVEMENT PROTEIN

The tobacco mosaic virus (TMV) 30K movement protein (MP) gene was inse rted into a full-length cDNA clone of barley stripe mosaic virus (BSMV ) RNA beta replacing the triple gene block (TGB). The resulting recomb inant ND-MPT genome, consisting of infectious wt transcripts of BSMV R NAs alpha and gamma, together with the hybrid RNA beta transcript, was inoculated onto test plants to study the functional compatibility bet ween the BSMV TGB-adapted genetic system and the tobamovirus transport gene. ND-MPT infected the inoculated leaves of Nicotiana benthamiana and Chenopodium amaranticolor, which are common hosts for the parental viruses; the size, growth rate, and morphology of local lesions on C. amaranticolor were influenced by the foreign MP gene. However, the hy brid virus failed to infect barley, N. tabacum (var. Samsun), and IV. clevelandii, the selective hosts. Thus, the TMV MP was able to functio nally substitute for the BSMV TGB-coded MPs, i.e., the 30K MP function ed independently of any other BSMV sequences. However, the TMV MP gene promoted the cell-to-cell movement in a host-dependent manner. (C) 19 95 Academic Press, Inc.