IDENTIFICATION AND PARTIAL CHARACTERIZATION OF ENDOGENOUS DOUBLE-STRANDED RIBONUCLEIC-ACID IN MULBERRY

Double-stranded ribonucleic acid (dsRNA) analysis of apparently health y red mulberry (Morus rubra L.) yielded four distinct dsRNA banding pr ofiles. dsRNA type 1 contained three dsRNA bands with approximate mole cular weights (MWs) of 12.0, 1.0, and 0.9 x 10(6), respectively. dsRNA type 2 contained two dsRNA bands with MWs of 1.0 and 0.9 x 10(6). dsR NA type 3 contained four dsRNA bands with MWs of 1.0, 0.9,0.89, and 0. 88 x 106. dsRNA type 4 contained three dsRNA bands with MWs of 1.0, 0. 88, and 0.87 x 10(6). No virus particles were associated with any of t he samples analyzed. All four types of dsRNA were resistant to DNase I and RNase A in high salt and susceptible to RNase A in low salt. Mulb erry dsRNAs were somewhat similar to endogenous dsRNAs (edsRNA) associ ated with other hosts. This is the first report of edsRNA associated w ith a deciduous tree.