Progress toward genetic engineering of phytoplasma- and virus-resistant crops: Phloem-specific expression of marker genes in transgenic cherry (left) and strawberry (right) plants.

Many agriculturally important plant diseases are caused by phytoplasmas, which are cell wall-less bacteria restricted to sieve elements in the phloem tissue of infected plants.

To mitigate phytoplasma diseases, we wish to develop genetically modified plants that will produce and deliver anti-microbial peptides specifically to phloem sieve elements where phytoplasmas reside and multiply.

As an initial step towards that goal, we established experimental procedures for efficient genetic transformation of strawberry and cherry plants and devised gene constructs that can deliver reporter molecules and pathogen-inhibiting peptides into phloem tissues of engineered plants.

The images show the presence of green fluorescent protein and ß-glucuronidase activity in engineered cherry (left) and strawberry (right) plants.