Potato Spindle Tuber Viroid-infected Tissues Contain RNA Complementary to the Entire Viroid

Abstract

Potato spindle tuber viroid (PSTV) RNA, labeled in vitro with 125I, was hybridized in solution to RNA prepared from uninfected and PSTV-infected Rutgers tomato plants and suspension cultures. Following hybridization to RNA from infected plants, 125I-labeled PSTV was converted from its single-stranded form to double-stranded [ds] RNA; this conversion did not occur to a significant extent when the 125I-labeled PSTV was incubated with RNA from uninfected tomato plants under identical conditions. Following fractionation of RNA from PSTV-infected tissue with 2 M-LiCl and chromatography on cellulose CF11 columns, the RNA species which hybridizes with the PSTV probe was enriched in those fractions which are also enriched for dsRNA. Fingerprint analysis of hybridized 125I-labeled PSTV following recovery from the hybrids demonstrated that all regions of the viroid are represented in the complementary strands present in these RNA preparations.