Fig 5.

Stem-loop II (SLII)-deficient mutants do not produce D RNA. (A) The RNAfold-predicted structures in the positive strand of D RNA and their calculated free energies in kcal/mole are shown. Deleted bases in ΔSLII^TGB1arm and ΔSLII^8Karm are represented by a delta (Δ). (B) Northern blot analysis to detect the DI in total RNA preparations recovered from the leaves of N. benthamiana inoculated with wt, ΔSLII^TGB1arm, and ΔSLII^8Karm inocula. The ³²P-labeled RNA probe specific for the 3′ UTR was used. (C) Accumulation of PMTV was measured by ELISA as indicated by absorbance values at 405 nm. Plant extracts were prepared from upper leaves at 14 dpi. The average absorbance of a healthy plant extract was equal to 0.15. ELISAs were conducted twice (n = 8).