1a. Objectives (from AD-416)
Culture ZC Liberibacter bacterium and confirm its pathogenicity.
1b. Approach (from AD-416)
The first step is to establish an in planta culture of Liberibacter. For in vitro culture, standard procedure for cultivation of fastidious prokaryotes will be followed. Liber A medium will be used as a starting point for cultivation. Growth of Liberibacter will be monitored by standard microbiological methods and by PCR detection. If Liberibacter are detected by PCR, various cultivation conditions and media compositions will be optimized for bacterial growth. Bacteria will be triple-cloned to obtain pure cultures. Transmission electron microscopy will be used for morphological characterization. Documents Reimbursable shared NIFA Agreement with Texas AgriLife Research.Log 41211.
3. Progress Report
This research is in support of Objective 1.A [Determine the epidemiology of exotic, emerging, re-emerging, and invasive diseases in California, including (but not necessarily limited to) Xf-caused diseases of horticultural, agronomic, and ornamental crops -- Identify naturally-occurring hosts of Xf and sharpshooter insect vectors as potential sources of inocula for infection of cultivated horticultural and agronomic crops] of the in-house project with the goal to investigate the pathogenicity of a newly found invasive bacterium, “Ca. L. solanacearum”. The importance of studying this bacterium is that it is a putative pathogen of potato Zebra Chip disease and the bacterium is phylogenetically related to “Ca. L. spp.” associated with citrus Huanglongbing. APHIS permits were obtained to receive potato samples from Texas and Washington. A batch of potato tissue culture with “Ca. L. solanacearum” has been received from Washington and the cultures were maintained in a secure growth chamber. Plant derived from ZC-affected potato plants grew very slowly or were stunted. We identified a location in California where ZC potatoes were found. Using these potatoes, we detected “Ca. L. solanacearum”, although titers were low. Other bacteria were also found in potato tubers. We documented that increased ZC symptoms (therefore more “Ca. L. solanacearum”), equate with lower sprouting/emergence rates.