Grant Information

DETECTION, IDENTIFICATION AND GENETIC ANALYSIS OF ¿CANDIDATUS LIBERIBACTER ASIATICUS¿, CITRUS HONGLONGBING BACTERIUM

Sponsoring Institution Agricultural Research Service/USDA
Status COMPLETE
Funding Source USDA INHOUSE
Reporting Frequency Annual
Project Director LIN H
Accession Number 423712
Project Number 5302-22000-010-18R
Dates 2011-10-01 - 2012-09-30
Recipient Organization AGRICULTURAL RESEARCH SERVICE

PARLIER,CA 93648
Keywords asiaticus
candidatus
genotyping
liberibacter
microsatellite
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. Conduct multi-locus microsatellite genotyping for Las strains from HLB-affected planta and psyllid samples collected from various geographic locations.
  2. Develop a comprehensive Las genotyping databases for identification and tracking the movement of Las isolates.
Methods (unparsed)

1. PCR-based detection and fingerprinting and fragment analyses of asiaticus isolates. 2. Construct allele frequency of genotyping data and conduct phylogenetic analysis of U.S. Las populations.

Project Timeline Tracking

Outputs

This research is in support of Objective 4 (Develop and assess strategies to manage bacterial diseases) of the in-house project. Huanglongbing (HLB) is one of the most destructive diseases of citrus. Since the first U.S. report of HLB in 2005, the disease has been observed in most citrus growing counties in Florida. To date, the insect vector, Asian citrus psyllid (ACP), has invaded and become established in California and Texas. Recently, HLB diseased citrus was reported in Texas and California. Reliable detection of HLB-associated bacteria is critical for development and implementation of strategies to eradicate new occurrences at an early stage. The goal of the project is to develop an HLB detection system for the identification and genetic determination of the source of invasions. Using multilocus DNA markers developed previously, a worldwide genotyping database for Candidatus Liberibacter species (presumptive causal agent of HLB) has been developed. Using this genotyping system, HLB-associated Liberibacter spp. in California and Texas were characterized. Genotype analysis revealed that Liberibacter strains identified in California were related to Southeast Asian groups. Strains identified in Texas matched genotypes from Florida and Mexico. The multilocus genotyping system is a useful tool for tracking spread of HLB-associated Liberibacter species and provides valuable information for development of effective control measures. To explore additional genome-based markers, the complete genome sequences of a Chinese strain of �Candidatus Liberibacter asiaticus� and a Brazilian strain of �Candidatus Liberibacter americanus� were determined. Research progress was reported quarterly to APHIS and results were presented at local and national scientific and nonscientific meetings.