3 0.143   CHN-D Nanning, Guangxi province 14 14 3.0 0.276   CHN-E Fuzhou, Fujian Province 7 5 2.1 0.320   CHN-F Tangshan, Yunnan Province 3 2 1.3 0.143   CHN-G Gangzhoou, Jiangxi Province 1 1 1.0 0.000

  CHN-H Guangzhou, Guangdong Province 1 1 1.0 0.000   CHN-I Hunan Province 1 1 1.0 0.000   China-overall 36 31 5.7 0.342 CAMBODIA CAM-A Pursat Province 7 6 2.4 0.341   CAM-B Battambang Province 4 4 1.9 0.304   Cambodia-overall 11 10 3.1 0.423 VIETNAM VIET Hung Yen Province, Hoa Binh Province, Hanoi 3 3 1.9 0.317 THAILAND THAI Protein Tyrosine Kinase inhibitor Unknown 1 1 1.0 0.000 TAIWAN TIW Unknown 1 1 1.0 0.000 JAPAN JPN Unknown 1 1 1.0 0.000 INDIA IND-A Anantapur District, Andhra Pradesh 7 7 2.4 0.297   IND-B Chittoor District, Wortmannin manufacturer Andhra Pradesh 6 6 2.0 0.254 MNK inhibitor   IND-C Kadapa District, Andhra Pradesh 4 4 1.9 0.250   IND-D Mahaboobnagar District, Andhra Pradesh 3 3 1.4 0.159   IND-E Nalgonda District, Andhra Pradesh 4 4 1.7 0.196   IND-F Prakasam District, Andhra Pradesh 4 3 2.4 0.540   IND-G Tirupati District, Andhra Pradesh 5 5 2.0 0.274   IND-H Kurnool District, Andhra Pradesh 1 1 1.0 0.000   IND-I Ludhiana District, Punjab 1 1 1.0 0.000   India-overall 35 34 5.4 0.360 Allele per locus: average number of alleles per locus Clone corrected data (removed repeated genotypes within a population) Genotype and genetic diversity A total of 117 genotypes (haplotypes) were identified

(Additional file 1). Haplotypes identified within the sample population were restricted to the boundaries of their country of origin. The genetic diversity observed in different countries and locations are summarized in Table 2. Isolates from China possessed the largest number of alleles (5.7 alleles per locus), followed by India (5.4 alleles per locus). Overall

haploid genetic diversities were the highest in Asian countries, followed by Brazil. The haploid genetic diversity of the Florida (USA) isolates was lowest among all the geographic groupings (Table 2). Genetic structure A UPGMA clustering analysis identified three major groups of ‘Ca. L. asiaticus’ (Figure 1). Isolates from India BCKDHB were clustered in a distinct group (group 3). Most of the isolates from China and other Asian countries, and Brazil were generally grouped in group 1. While some isolates from Florida occurred in group 1, most isolates from Florida were clustered in group 2 (Figure 1). Figure 1 UPGMA dendrogram showing the genetic relationships of ‘ Candidatus Liberibacter asiaticus’ isolates from different locations within an individual country as well as from different countries (from Asia and Americas). Clone-corrected data were used for constructing the dendrogram based on DA distance [22]. Only bootstrap values > 25% are shown. The STRUCTURE analysis based on Bayesian modeling further assessed the genetic structure of ‘Ca. L. asiaticus’. This approach utilizes statistical methods to determine the relationships among the isolates without prior population information.