Potato spindle tuber viroid infections mediated by the Ti plasmid of Agrobacterium tumefaciens.

Full length copies of potato spindle tuber viroid (PSTV) were introduced into plant cells using an Agrobacterium tumefaciens vector. Crown galls containing the PSTV DNA were induced on tomato plants, and the plants analysed for systemic replication of the viroid. Two separately derived multimeric PSTV insertions in the T-DNA were infectious on every plant inoculated. However, monomeric PSTV gave rise to significant levels of infection only when an adjacent plant promoter could direct transcription of + strand PSTV RNA. Our results suggest that this experimental system will be useful for the analysis of viroid replication. A second application of the results may be the use of systemic viral infection as a sensitive assay for transient expression of transformed DNA. re]19850917 rv]19851203 ac]19851210.