TRANSFECTION OF WHOLE PLANTS FROM WOUNDS INOCULATED WITH AGROBACTERIUM-TUMEFACIENS CONTAINING CDNA OF TOBACCO MOSAIC-VIRUS

We engineered cDNA of tobacco mosaic tobamovirus (TMV) into Agrobacter ium tumefaciens for inoculation of plant cells. The resulting bacteria l strains were used to transfect tobacco (Nicotiana tabacum cv. Xanthi and Xanthi/nc) with wild type and a defective virus. Lesion formation on Xanthi/nc tobacco was used to measure the timing and efficiency of transfection. Infections mediated by Agrobacterium produced lesions a n average of two days later than infections produced by inoculation wi th virions. The addition of approximately 80 bp of non-viral sequences to the 5'-end of TMV transcripts abolished transfection. Transcripts with non-viral sequences at the 3'-end initiated infections, while pre cise transcript termination with a synthetic ribozyme sequence increas ed transfection frequencies two-fold. Culture conditions reported to i nduce genes of the vir region of the Agrobacterium Ti plasmid also inc reased the transfection frequency approximately two-fold. Therefore, i n addition to the pararetroviruses and geminiviruses previously descri bed, 'agroinoculation' may be used to infect plants with plus-sense RN A viruses.