Effects of plant hormones on white clover mosaic potexvirus double-stranded RNA

The double-stranded RNAs (dsRNA) produced during the replication of white c lover mosaic potexvirus (WClMV) in the primary leaves of Phaseolus vulgaris during the 10 days following inoculation were investigated. Replication of a large dsRNA fragment (dsRNA 1) occurred within 24 h of inoculation and p robably represents the replicative form of the genomic RNA. A second dsRNA fragment (dsRNA 5) appeared at day 3, and four other dsRNAs were detected f rom day 5; the putative functions of these are unknown, however their appea rance coincided with a rapid increase in virus titre. Hormone treatments th at inhibited virus replication altered the production of these dsRNAs. Dihy drozeatin, jasmonic acid and salicylic acid inhibited production of all dsR NAs except dsRNA 1, while 1-amino-1-cyclopropane carboxylic acid reduced th e levels of dsRNAs produced but did not alter the pattern of expression.