Collecting and preserving plant DNA for huanglongbing diagnosis in citrus samples from China

Accurate and sensitive detection of Citrus Huanglongbing associated ‘Ca. Liberibacter’species, not currently reported in the European and Mediterranean area, is an imperative need to define certification programs, to prevent introduction of the bacteria and/or their vectors in the unaffected areas, and to delineate efficient management strategies in those areas where the disease has spread. In this study, we compared different citrus sample preparation procedures for PCR based detection methods of ‘Candidatus Liberibacter asiaticus’, in order to find out the best a way to transport and preserve samples of Shatangju mandarin and fingered citron obtained during a survey in citrus orchards in Guangdong in 2012. Results show that silica gel dehydrated midrib and bark citrus samples are amenable for DNA extraction and further processing by PCR and real-time PCR. FTA plant collecting card were useful for easily collect DNA samples in the field and processing by real-time PCR although at a lower concentration than extracted DNAs.