Ability to sythesize amino acids. The selective inhibition of a pathway unique to plants should be more ecologically sound. Totipotency - The ability to regenerate an entire plant from a single cell through tissue culture. Thus, if you introduce DNA into a single cell, the regenerated plant will have that gene in all the cells. Plant genes are often found in gene families - Thus plants have evolved to specifically express genes in certain times in development and specific tissues by altering the regulatory elements that control gene expression.
Most phytopathogenic bacteria are either gram negative or positive.
Phytoplasmas Many phytopathogenic bacteria have a disease cycle where then can colonize a host as a leaf epiphyte as a prelude to the pathogenic phase. Many phytopathogenic bacteria do not directly enter the cell, but multiply in the intercellular space between the cells. These bacteria gain entrance through natural openings such as stomata, hydathodes and wounds. Thus, these bacteria have evolved a series of virulence factors that are secreted from the bacterium. This is usually based on the ability of a bacterium to cause disease on a specific plant.