1a. Objectives (from AD-416):
1. Cultivation of "Ca. L. solanacearum" through in vitro and in planta approaches. 2. Morphological, physiological and genetic characterization of "Ca. L. solanacearum".
1b. Approach (from AD-416):
1. Identify and obtain "Ca. L. solanacearum" infected potato materials from fields in California. Maintain the infected potato in greenhouse. 2. Through grafting, transer the bacterium to different types of plants and evaluate their capacity to host the bacterium. 3. Variate in planta cultivation conditions to optimize bacterial growth. 4. Develop tissue culture, insect cell culture and in vitro culture methods for "Ca. L. solanacearum. 5. Use PCR and electron microscope to monitor the bacterial growth.
3. Progress Report:
This research is in support of Objective 1.B. (Genome sequence analyses of plant pathogens) of the in-house project. Recent research on “Candidatus Liberibacter solanacearum”, the putative pathogen of potato zebra chip disease, indicated that the bacterium consisted of at least two genetic types in the U.S. that could be related to variation in disease development. This research focused on developing polymerase chain reaction (PCR) assays for specific detection of each bacterial genetic type. Sequences of a gene of the zebra chip bacterium were analyzed and differences among types were identified. Two PCR primer sets were designed according to the sequence differences. PCR specificity was confirmed by samples collected from diseased-plants. The developed PCR assays provide a quick and sensitive solution for differentiation of pathogen variants which is critical for further biological evaluation of the zebra chip bacterium and also for disease management.