New Strains of Candidatus Liberibacter asiaticus in Citrus Plants in Bali

Abstract

Candidatus Liberibacter asiaticus is the most widely known bacteria causing citrus greening (Huanglongbing) from three species of Candidatus Liberibacter. This study was conducted to ascertain the phylogenetic relationship between Can. Liberibacter asiaticus Indian isolates which have a higher diversity in 16S rDNA with Asian isolates in general. An citrus leaves samples with CVPD disease symptoms were collected from several locations in Bali. Detection of Can. L. asiaticus in the sample was performed by PCR using a 16S rDNA-specific primer F: 0I1 and R: 0I2c. Based on the DNA amplification results, six samples taken from Citrus nobilis reacted positively, and each one taken from C. amblycarpa, C. aurantium and C. grandis were also reacted positively. DNA of nine positive samples were purified and sequenced. The sequencing results showed a close relationship between C. nobilis samples with C. aurantium at a distance of 0.000, but the relationship is relatively far away with the other seven samples and with strains of Poona India, L. africanum strains of Nelspruit South Africa and nine isolates Can. L. asiaticus accessed from GenBank NCBI is with a distance of 0.600-0.603. Two samples (JBC1311 and JBC1351) are different from Indian Poona strain in Purine base positions with Pyrimidine, and Pyrimidine base positions with Purines in the 16S rDNA sequence. Based on these results, one sample each taken from Citrus nobilis JBC1311) and C. aurantium (JBC1351) are considered as new strains and different from other strains occurred in Bali, and also different from the strains of Poona (India) and the strain of Nelpruit (South Africa), while 7 (seven) other samples are the same strains.

Keywords: Citrus greening ,CVPD, Candidatus Liberibacter asiaticus, 16S rDNA