Increased Susceptibility to Pseudomonas syringae pv. syringae and Pseudomonas viridiflava of Kiwi Plants having Transgenic rolABC genes and its Inheritance in the T1 Offspring

The staminate kiwi (Actinidia deliciosa A. Chev) cv. GTH (Late Yellow Hayward) showed high resistance to the pathogens Pseudomonas syringae pv. syringae and Pseudomonas viridi¯ava, contrary to the pistillate cv. Hayward which was highly susceptible to both bacteria. The resistant staminate GTH acquired susceptibility when transformed with rolABC of Agro- bacterium rhizogenes. This susceptibility was inherited by the T1 o€spring containing rolABC genes, derived by crossing pollen of transgenic rolABC GTH with the pistillate cv. Hayward. The susceptibility was probably correlated to high nitrogen content in the leaves of the rolABC plants. The higher susceptibility to P. s. pv. syringae than to P. viridi¯ava could be correlated with the high degree of auxin production by ®rst bacterium. The high resistance to both bacteria of the staminate GTH was inherited by all the o€- spring lacking rolABC genes. The possibility of redu- cing susceptibility of rolABC plants to the pathogens by applying fewer fertilizers in the orchards, which would reduce both costs and environmental impact, is discussed