Exploring the pathology of zebra chip disease

Zebra chip disease of potato presents as dark stripes and streaks when a potato chip is fried. This recently-emerged disease renders potatoes commercially unacceptable and is a major problem in New Zealand and worldwide. 

The disease is caused by the bacteria Candidatus Liberibacter solanacearum, vectored by the tomato potato psyllid, which has been the primary target for disease management strategies (mainly insecticide and more recently biocontrol). However, management strategies that directly target the bacteria are required to control this plant pathogen.

Progress has been hampered by the difficulty in characterising the proteins in this organism. The proteins are not easily produced and purified in standard laboratory systems. This bacteria cannot be grown in the laboratory and previous efforts to purify active proteins have been unsuccessful. 

This study, by PhD student Jenna Gilkes, is part of a collaboration between scientists at the University of Canterbury and Plant & Food Research and aimed to develop a general method to produce and purify ‘difficult’ bacterial proteins in their native (active) state. 

This is the first time an active protein has been successfully purified from this organism. This will help future studies understand how disease is caused and will help in the development of novel antimicrobial strategies to stop this pathogen.

Support for this study was provided by Callaghan Innovation, the Marsden Fund, the Ministry of Business, Innovation and Employment, the Biomolecular Interaction Centre and Plant & Food Research.

Journal Reference:

Gilkes, J, Sheen, C, Frampton, R, Smith, G, Dobson, R 2019. The First Purification of Functional Proteins from the Unculturable, Genome-Reduced, Bottlenecked α-Proteobacterium ‘Candidatus Liberibacter solanacearum’. Phytopathology 109 (7): 1141-1148 Doi.org/10.1094/PHYTO-12-18-0486-R