CANDIDATUS LIBERIBACTER ASIATICUS CAUSING CITRUS HUANGLONGBING ON CITRUS SINENSIS IN BANGLADESH

Citrus huanglongbing (greening) is one of the important diseases of citrus in Asia (Bove, 2006). The symptoms include blotchy chlorosis and/or mottling of the leaves, stunted growth, poor root growth, small, green, and malformed fruits and decline of the trees. The disease is caused by the phloem-limited unculturable fastidious bacteria Candidatus Liberibacter asiaticus (CLas), Ca. L. africanus (CLaf), and Ca. L. americanus (CLam) (Bove, 2006; Jagoueix et al., 1994). Among them CLas is the most widespread (e.g., Asia, Brazil and North America). In recent years the presence of huanglongbing was suspected in different regions of Bangladesh. To establish whether this is the case, in July, 2016 symptomatic plant samples of Citrus sinensis were collected from four citrus-growing areas of the country: Jaintapur (Sylhet), Akbarpur (Moulvibazar), Dighinala (Khagrachari) and Hathazari (Chittagong). The samples were analyzed by polymerase PCR using the ‘CLas’ specific primers A2 (5’-TATAAAGGTTGACCTTTCGAGTTT-3’) and J5 (5’-ACAAAAGCAGAAATAGCACGAACAA-3’) which amplify a partial sequence of the β-operon (rplKAJL-rpoBC operon) of ribosomal protein genes (Hocquellet et al., 1999). A product 703 bp in size specific to Ca. L. asiaticus was amplified, sequenced and deposited in GenBank (accession No. KX826950). The nucleotide sequence of the recovered CLas shared 100% sequence identity with other Ca. L. asiaticus strains from NCBI database (e.g. KC477384, KT164844, KC133065). To our knowledge this is the first molecularbased detection of Candidatus Liberibacter asiaticus infecting Citrus sinensis in Bangladesh. © 2017, Edizioni ETS. All rights reserved.