Grant Information

DEVELOPMENT OF SSR MARKERS FOR DETECTION, GENOTYPING, PHENOTYPING AND GENETIC DIVERSITY ASSESSMENT OF CA. LIBERIBACTER STRAINS IN FLORIDA

Sponsoring Institution Agricultural Research Service/USDA
Status COMPLETE
Funding Source USDA INHOUSE
Reporting Frequency Annual
Project Director LIN H
Accession Number 420857
Project Number 5302-22000-010-05T
Agreement Number 420857
Dates 2011-03-18 - 2013-01-31
Recipient Organization AGRICULTURAL RESEARCH SERVICE
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PARLIER,CA 93648
Keywords (ssr)
asiaticus
candidatus
genotyping
huanglongbing
liberibacter
repeat
sequence
simple
Research Effort Applied (30%)
Basic (60%)
Developmental (10%)
Classification Parameters
Knowledge AreaSubject of InvestigationField of SciencePercent
212 - Pathogens and Nematodes Affecting Plants 999 - Citrus, general/other 1040 - Molecular biology 100%
Goals / Objectives
  1. Perform genome-wide sequence analysis to identify Simple Sequence Repeat (SSR) loci.
  2. Genotyping and phenotyping of CLas strains, characterizing virulent strains, host pathogen interactions; adaptation, selection and strain - strain competition.
  3. Analyzing CLas population structures, assessing genetic diversity of CLas in Florida populations.
Methods (unparsed)

1. Complete genome gaps from current draft genome using long distance PCR and genomic walking techniques. 2. PCR and fragment analyses of asiaticus isolates collected from Florida populations. 3. Conduct molecular variance analysis to assess hierarchical structures of pathogen population in Florida.

Project Timeline Tracking

Outputs

This research is in support of objective 1 of the parent project, the goal of which is to investigate genetic diversity and population structure of bacterial pathogens of plants. Results from this study identified three major genetic lineages of 'Candidatus' Liberibacter asiaticus, the bacterial pathogen associated with citrus huanglongbing (HLB). Populations from Brazil appear to be genetically similar to east- southeast Asian populations, suggesting the possibility of a common origin. A majority of the isolates detected from Florida clustered in a separate group of unknown origin. However, several less-common sub-groups from Florida appear to be closely related to isolates from Asia. Thus, the data indicate that the recent outbreak of HLB in Florida likely occurred through multiple introductions from different sources. The molecular markers developed in this study provided adequate discriminatory power for detection, identification and population genetic studies of Las.