Zebra Chip disease (ZC) is caused by, 'Candidatus Liberibacter solanacearum' (Ca. L. solanacearum) which is vectored by the tomato/potato psyllid (TPP). The disease results in the development of blacklines in fried potato tubers which renders them commercially unacceptable. ZC has caused significant economic losses to the New Zealand potato industry, which has resulted in a need for further understanding of the biology and aetiology of this unculturable bacterium. The completion of the Ca. L. solanacearum genome in 2011 (Lin et al. 2011) determined the presence of putative bifunctional genes.
The research aimed to determine whether these annotated bifunctional genes were differentially expressed in vector (TPP) and in host potato plants. Primers were developed for the bifunctional genes of Ca. L. solanacearum and for a number of potential housekeeping/reference genes to determine differential changes in gene expression. Results showed that the bifunctional AICAR transformylase/IMP cyclohydrolase (ATIC) was the most expressed gene in TPP and plants whilst the membrane protein, SECDF, was upregulated in plants. The results suggest that these genes could play a role in Ca. L. solanacearum pathogenicity. Furthermore, these genes and the proteins they encode could potentially be novel targets for the development of antibacterials as many of the current disease management strategies target the psyllid.