The objective of this work was to identify Brazilian isolates of Ralstonia solanacearum according to phylotypes and sequevars, to determine their genetic diversity, to associate the pathogen genetic structure with its taxonomy and geographical origin, and to identify a specific molecular marker to diagnose banana moko disease. A group of 33 isolates of R. solanacearum, from the collection of Embrapa Tabuleiros Costeiros, collected from different plant hosts, was characterized using the repetitive extragenic palindromic sequence-based PCR (rep-PCR) and RAPD. From this group, 19 belonged to the pathogen race 2 and 14 to the race 1, and 15 isolates were associated with banana crop. Phylotypes and sequevars were characterized and determined by Multiplex PCR. It was verified that the isolates belonged to phylotypes II (82%) and III (12%). All isolates from banana plants belonged to phylotype II. The RAPD technique was efficient in grouping these isolates according to their geographical origin; however, it requires a large number of molecular markers. It was possible to establish the relationships among the isolates by rep-PCR. The enterobacterial repetitive intergenic consensus primer (ERIC) made it possible to separate the isolates according to the race, and the REP primer allowed for the discrimination among phylotypes.These were the two mostinformative analyses.
Musa; molecular marker; banana moko disease; bacterial wilt; rep-PCR; genetic variability
