L. asiaticus’ has provided information on the metabolic features
of this bacterium and key insights into HLB pathogenesis [11]. In addition, the genome sequence has facilitated the development of DNA markers for genetic analysis; these molecular genetic markers are critical for understanding the genetic diversity of global populations and the epidemiology of HLB. DNA markers have been used for characterization selleck products of microbial populations associated with plant diseases, including RAPDs, SNPs, MLST and SSRs (microsatellites) [12–15]. Molecular genetic markers not only aid in the general characterization of a given population, but can help identify the source of an introduced pathogen [16]. Among Pitavastatin the three HLB-associated Liberibacter species, ‘Ca. L. asiaticus’
is the most widespread and is responsible for increasing economic losses of citrus industries. Much attention has been drawn by researchers in the last few years to the importance of understanding the epidemiology and ecology of the disease associated with ‘Ca. L. asiaticus’. ‘Ca. L. asiaticus’ isolates were characterized in some previous studies; most of these studies focused on the Asian continent and utilized LCZ696 conserved genes as genetic markers. For example, southeast Asian isolates were characterized by sequencing the 16S rDNA and 16S/23S regions, omp, the rpl gene cluster, and the bacteriophage-type DNA polymerase [17]. The 16S rDNA was employed for understanding genetic diversity of ‘Ca. L. asiaticus’ in India [18] and a prophage gene was used to reveal variations in China [19]. However, genetic variation within conserved genes has limited discriminatory power to differentiate closely-related isolates within populations. Microsatellite DNA markers associated with hypervariable
Non-specific serine/threonine protein kinase sequence regions can provide sufficient resolution for differentiating closely-related isolates and for tracking genotypes of interest; additionally, these markers may help identify the source of invasive strains. Recently, similar types of markers have been used for differentiating ‘Ca. L. asiaticus’ in Japan [20]. Chen et al. [21] studied populations from Guangdong province in China and Florida in the United States. However, the single variable locus used in that study provided limited characterization of ‘Ca. L. asiaticus’ genetic diversity. Here, we report a panel of seven polymorphic microsatellite markers for conducting genetic analyses of ‘Ca. L. asiaticus’ isolates from Asia (India, China, Cambodia, Vietnam, Thailand, Taiwan, and Japan), North America (Florida, USA) and South America (São Paulo, Brazil). The microsatellite profile for each isolate was compared with all members of the sample set to make predictions on the possible origin and dissemination of HLB in Florida. Results PCR amplification and characteristic of microsatellite loci A total of 287 ‘Ca. L.