Detection of genetic diversity among Indian strains of _Xanthomonas campestris_ pv. _mangiferaeindicae_ using PCR-RAPD

Abstract

The randomly amplified polymorphic DNA (RAPD) technique was used to investigate the genetic diversity in 6 strains of _Xanthomonas campestris_ pv. _mangiferaeindicae_ (_Xcmi_), the causal pathogen of mango bacterial canker disease (MBCD). The RAPD analysis was also intended to identify molecular markers, specific to the species to develop PCR-based markers for detection of _Xcmi_ in mango field and planting materials. Twenty RAPD primers (CP 1-CP 20) were evaluated to establish molecular characters and genetic variability in the genome of _Xcmi_. Among these, only 4 were found efficient for development of reproducible banding pattern. It has been observed that the largest and smallest amplified RAPD products were of 2.036 and 0.201 kbp. A total of 136 bands were scored against 6 strains of _Xcmi_. There was 7.66 per cent polymorphism in individual isolates which indicates significant polymorphism among the evaluated strains, with mean difference of 0.33 (_Xcmi_ 2 vs. _Xcmi_ 8) and 0.29 (_Xcmi_ 10 vs. _Xcmi_ 12). However, the single linkage euclidean distances were statistically significant (P>0.05), i.e., 0.58. The markers CP 5, 10, 16 and 19 were amplified in all the strains with polymorphic alleles, which indicates that these markers could be used for rapid detection of genetic variability in _Xcmi_ strains