DNA constructs and methods to impart resistance to papaya ringspot virus on plants

摘要

The present invention is directed to a DNA construct comprising a first DNA molecule having a length insufficient to independently impart resistance to papaya ringspot virus to plants transformed with said first DNA molecule, wherein the first DNA molecule is from a DNA molecule encoding a papaya ringspot virus coat protein and is at least 110 nucleotides in length. The construct also comprises a second DNA of at least 400 nucleotides in length, which is coupled to the first DNA molecule so that the first and second DNA molecules collectively achieve post-transcriptional silencing and impart resistance to papaya ringspot virus. Alternately, the DNA construct can comprise a plurality of DNA molecules each of which is at least 110 nucleotides and at least one of which is from a DNA encoding a papaya ringspot viral coat protein and is insufficient in length to independently impart resistance to papaya ringspot virus to plants.