Plant Molecular Vehicles: Potential Vectors for Introducing Foreign DNA into Plants

INTRODUCTION 609 POTENTIAL VEHICLES DERIVED FROM NATURALLY OCCURRING PLANT VECTORS AND PATHOGENS 612 Agrobaclerium Ti-plasmids 612 Potential use as a vehicle ........•.•.........••••.• •.• ••.• • •.•.... 615 CaulimoYiruses 619 Possible use as a vehicle ....... 623 Geminiviruses 625 RNA Viruses: Genomic and Satellite RNAs 626 Viroids 631 POTENTIAL VEHICLES DERIVED FROM UNSTABLE PLANT GENOME COMPONENTS 633 Mitochondrial Extrachromosomal Elements in Maize 633 Nuclear Controlling Elements in Maize 636 POTENTIAL VEHICLES DERIVED FROM STABLE PLANT GENOME COMPONENTS 637 DELIVERY SYSTEMS 639 PROSPECTS AND CONCLUSIONS 640