Rep-PCR reveals a high genetic homogeneity among Ugandan isolates of Xanthomonas campestris pv musacearum

Abstract

Wilting of plants incited by a bacterium, Xanthomonas campestris pv musacearum (Xcm), was first described on Ensete (Ensete ventricosum) and later bananas (Musa species) in the highlands of Ethiopia in 1968. Although the spread outside Ethiopia remained unreported for several decades, an epidemic of the disease on banana in Uganda was observed in 2001, in the districts of Mukono and Kayunga. Since then, the disease has spread into almost three quarters of the major banana growing areas in Uganda. It has also been confirmed affecting banana plantations in the Democratic Republic of Congo (DRC) and Rwanda. Repetitive sequence based genomic fingerprinting that uses a PCRmediated amplification of DNA sequences located between specific interspersed sequences of highly conserved elements in prokaryotic genomes was used to characterize a collection of Xcm isolates from banana in Uganda. Fingerprints of bacterial isolates collected from Xcm symptom bearing banana plants grown in production fields from 10 districts including Kayunga, Masindi, Luwero, Kampala, Kiboga, Lira, Wakiso, Kibale and Nakasongola revealed similar patterns. Cluster analysis of pair wise similarity values performed using unweighted pair group method with arithmetic averages clustering technique did not generate any differences in the fingerprint patterns either. The implications of this genetic homogeneity on the origin and management of Xcm is discussed here.