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Etiology

Effects of Low-Molecular-Weight RNA and Temperature on Tomato Bushy Stunt Virus Symptom Expression. B. I. Hillman, Research assistant, Department of Plant Pathology, University of California, Berkeley 94720; T. J. Morris(2), and D. E. Schlegel(3). (2)(3)Associate professor, and professor, Department of Plant Pathology, University of California, Berkeley 94720. Phytopathology 75:361-365. Accepted for publication 1 October 1984. Copyright 1985 The American Phytopathological Society. DOI: 10.1094/Phyto-75-361.

Low-molecular-weight RNA associated with tomato bushy stunt virus (TBSV) infection altered symptom expression in several experimental hosts. The linear, single-stranded, low-molecular-weight RNA was encapsidated in TBSV-encoded protein. In addition, infected tissue contained a double-stranded (ds) form of this molecule. The most obvious symptom modification induced by the low-molecular-weight RNA was attenuation in Nicotiana clevelandii. At elevated temperatures (27 C), symptoms induced by TBSV alone and in combination with the low-molecular-weight RNA differed from those induced at a lower temperature (16 C). In N. clevelandii, high-temperature attenuation of symptoms was similar, but not identical to, that caused by the low-molecular-weight RNA. This symptom change was associated with changes in the dsRNA species accumulating in N. clevelandii as a result of virus infection. Among these changes was the suppression of low-molecular-weight RNA replication.