Citrus greening disease (HLB) on Citrus reticulata (Mandarin) caused by Candidatus Liberibacter asiaticus in Bangladesh

Citrus greening or Huanglongbing (HLB) is one of the most severe diseases of citrus worldwide and no cure is available at present. Currently molecular techniques based on polymerase chain reaction (PCR) are mainly used for the identification of HLB disease. The aim of this study was to identify the causal pathogen of citrus greening disease in Bangladesh. A total of eight mandarin orange leaf samples from three citrus growing areas viz. Moulvibazar, Sylhet and Khagrachari were collected on the basis of visual investigation demonstrating blotchy mottle symptoms. The genomic DNA was extracted from midribs of each leaf sample and subjected to the PCR. Species specific primers A2/J5 was used to amplify a partial sequence of β-operon (rplKAJL-rpoBC operon) of ribosomal protein gene. An amplicon size of 703 bp specific to the Candidatus Liberibacter asiaticus confirmed its presence. BLAST homology search with the sequenced data showed 99% identity with the sequence database of Candidatus Liberibacter asiaticus deposited in GenBank. These results confirmed the prevalence of Candidatus Liberibacter asiaticus causing citrus greening in Bangladesh. •Citrus greening disease was identified.•Genomic DNA was extracted from midribs of each leaf sample.•A partial sequence of β-operon (rplKAJL-rpoBC operon) of ribosomal protein gene was detected.•An amplicon size of 703 bp specific to the Candidatus Liberibacter asiaticus (Las) confirmed its presence.•BLAST homology search with the sequenced data showed 99% identity with sequences of the Las deposited in GenBank.