Analysis on causes of polymorphic PCR bands in nonculturable endophytes amplification

Abstract:

[Objective] This study was to investigate the genetic nature of multiple amplicons from PCR experiments on ‘Candidatus Liberibacter asiaticus’ infected citrus samples and to provide reference for molecular biological studies of fastidious prokaryotes. [Methods] Two short tandem repeats (STR) loci in the ‘Ca. L. asiaticus’ genome were amplified by conventional PCR. PCR products were separated by PAGE. Polymorphic bands were collected, cloned, and sequenced. [Results] The primers from the two STR loci generated multiple amplicons from a single ‘Ca. L. asiaticus’ infected citrus sample. Sequence analyses showed that these amplicons could be from ‘Ca. L. asiaticus’, other bacteria and citrus host. [Conclusion] The main source of amplicon variations was due to changes of STR numbers in the targeted loci. However, amplification of host and endophytic bacterial DNA could also contribute to the multi-band phenomenon.