01923naa a2200181 a 450000100080000000500110000800800410001910000160006024500730007626000090014930000140015850001210017252013210029365000120161470000150162670000170164177300830165816442311993-09-17       1991    bl uuuu     u00u1 u    #d1 aJARUPAT, T.  aAdditional factors affecting dsNRA analysis of citrus tristeza virus  c1991  ap.137-145  aConference of the International Organization of Citrus Virologists, 11., 1991, Riverside, California, Proceedings...  aWe have investigated factors that may have an effect on dsRNA analysis of citrus tristeza virus (CTV). Storage of bark tissue and purified dsRNA at-20 C four up to at least 4 yr and repeated freezing and thawing of each of them appeared to have no detrimental effect on the quality of dsRNA detected by polyacrylamide gel eletrophoresis. The aqueous phase following phenol extraction could by stored at room temperature or at 4 C with of without ethanol (ajusted to 16.5%) for at least 2 weeks. Buffer saturated phenol which has been kept at room temperature for 2.5 yr was still useful for CTV dsRNA extraction. DsRNA extraction could be done withou adding nuclease inhibitors, i.e. bentonite or macaloid. Precipitated dsRNA could be recovered by centrifugation immediately after addition of ethanol and sodium acetate. Hosts which yielded good dsRNA were Pineapple, Navel, and Valencia sweet orange and the scions of Madam Vinous sweet orange on sour orange rootstock. Shoots from the sour orange rootstock gave poor results. Green bark tissue from the older part of the current shoot usually gave a better result than tissue from the young tender shoot tip and the old brown stem from previous flushes. DsRNA results were least acceptable in the summer from various well infected screenhouse grown citrus species.  aDoença1 aLEE, J. G.1 aDODDS, J. A.  tRiverside, California: International Organization of Citrus Virologists, 1991.