Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 4/25/2006
Publication Date: 7/29/2006
Citation: Mello, A.F., Yokomi, R.K., Melcher, U., Chen, J., Fletcher, J. 2006. Assessment of Genetic Diversity in Spiroplasma citri by RAPD, rep-PCR and Bacteriophage Primers. Meeting Abstract. Phytopathology 96:S77
Technical Abstract: Spiroplasma citri causes stubborn disease in citrus. Production losses attributed to this disease in California and Arizona was significant in the 1970s but subsequently become minor until a recent re-emergence of the disease. The increased impact could be due to the presence of one or more new pathogen strains. The aim of this study was to evaluate repetitive extragenic palindromic elements (rep), random amplified polymorphic DNA (RAPD) and spiroplasma bacteriophage insertions as discriminative techniques to assess the genetic diversity among isolates and thereby evaluate the pathogen's evolutionary history and specificity to hosts and locations. Culture suspensions, or extracted and purified DNA, from ten isolates from different locations were used as PCR templates. Three rep (BOX, ERIC and REP), five RAPD and three bacteriophage primers were used in triply replicated PCR experiments. BOX was the only rep-PCR primer to produce reproducible differential band patterns in the evaluated isolates. One bacteriophage primer discriminated among the isolates, amplifying a DNA fragment unique to four isolates. One RAPD primer revealed a strain-specific band and a second primer yielded two bands that discriminated among isolates. These data suggest that there is genetic variability among populations of S. citri and that rep-BOX, one bacteriophage and some RAPD primers are useful to evaluate such diversity.