Molecular detection of Candidatus liberibacter asiaticus, the causal organism of huanglongbing (Citrus greening) in Faisalabad, Pakistan for Huanglongbing management

Abstract

Huanglongbing is an extremely dangerous disease of citrus. It is caused by different species of Candidatus Liberibacter bacterium: Candidatus Liberibacter asiaticus, Candidatus Liberibacter americanus and Candidatus Liberibacter africanus. The bacterium is transmitted from one plant to other by psyllid vector and through budding/grafting of infected plant material. For the diagnosis of huanglongbing disease citrus orchards: Square 9, citrus research area Plant Pathology and Post Graduate Agriculture Research Station of the University of Agriculture, Faisalabad, Pakistan were surveyed in 2010-11. Conventional PCR was performed by using 16S rDNA primer OI1/OI2c and Liberibacter asiaticus gene (β operon) specific primer A2/J5. Leaves were used from Citrus sinensis cultivar succari for the detection of huanglongbing pathogen. Out of 30 samples collected from Post graduate Agriculture Research Station, Faisalabad, 21 (70%) belonging from seven symptomatic trees were amplified and produced amplicons of 1160bp and 703 bp from OI1/OI2c and A2/J5 primers respectively in 2011, that confirmed the presence of Candidatus Liberibacter asiaticus in the samples. The diagnosis of disease will be helpful for future huanglongbing management experiments. According to our knowledge this is the first report of huanglongbing detection at molecular level from the University of Agriculture, Faisalabad, Punjab, Pakistan.