RAPD and rep PCR-based fingerprinting of vascular bacterial pathogens of Musa spp.

Abstract

Polymerase chain reaction (PCR) amplification with random decamer primers, and primers targeted to conserved repetitive sequences were used to investigate the genetic relationship between strains of Ralstonia solanacearum that cause the 'moko' and 'bugtok' vascular wilt diseases of banana and plantain (Musa spp.). The closely related bacteria R. pickettii, Pseudomonas syzygii and the banana blood disease bacterium were also included in this study. Data from several PCR fingerprints were collated by cluster analysis and principal coordinate analysis. Random Amplified Polymorphic DNA (RAPD) analysis divided the isolates into three groups. Group 1 contained a subset of Central American R. solanacearum moko strains. Group 2 consisted of the blood disease bacterium, P. syzygii and some R. solanacearum isolates from clove trees whilst group 3 comprised South-east Asian moko and bugtok isolates as well as another subset of Central American moko strains. Fingerprinting by PCR amplification with repetitive primers (rep-PCR) produced groupings broadly concurrent with those obtained from RAPDs. Both sets of groupings supported previous subdivisions made within R. solanacearum on the basis of rRNA fingerprints and 16S rRNA sequences, and the data lend support to the renewed description of the blood disease bacterium either as a separate species or as a subspecies within R. solanacearum.