Development of IL-60 system in potato reduces zebra chip symptoms

The causal agent of Zebra Chip (ZC) of potato was recently identified as a species of the plant-infecting bacterium Candidatus Liberibacter phyllarous, which is transmitted by the potato psyllid. IL-60 is a plant expression vector which permits expression of desirable transcripts for protective protein production in plants. This system is also being examined as a method to induce gene suppression, RNAi, in plants. In this study, potato tubers from ZC infected stocks were planted; when the plants reached the 5 leaf stage of development, they were randomly selected to receive 1 of 3 treatments: T1-GUS + IL-60 (GUS is a reporter control); T1-PRN + IL-60 (PRN is a protein known to reduce bacteria); and a control (water injection). At two week intervals for 12 weeks, tissue samples from plants were collected and tested for the presence of PRN, GUS, and Liberibacter. At the end of the trial, tubers were collected, sliced and fried to determine ZC status. GUS and PRN were both detected up to 12 weeks following injection indicating successful introduction. Preliminary data showed a reduction in `chip burn" in the PRN treated potato.