The Determination of the Genetic Diversity and Relative Aggressiveness among Ten Isolates of Ralstonia solanacearum in Trinidad: Results from a Pilot Study

Abstract

Bacterial wilt caused by Ralstonia solanacearum is a major plant disease in the tropical and sub-tropical regions of the world. Ralstonia solanacearum is a soil borne pathogen and is well noted for its considerably wide host range and it’s worldwide distribution. The pathogen exists as an array of biotypes with varying cultural, physiological and pathogenic traits, (Buddenhagen and Kelman, 1964). Traditionally, the pathogen is classified into 5 biovars based on the utilization of certain sugars and sugar alcohols and into three races based on host range. Both methods subdivide the pathogen into two large genetically diverse groups. The use of molecular methods to assess the genetic diversity of Ralstonia solanacearum has resulted in a greater understanding of the pathogen. The species has been separated into two divisions based on restriction fragment length polymorphism (RFLP) data, division 1 consisting of biovars 3, 4 and 5, and division 2 consisting of biovars 1,2 and N2, (Cook et al, 1989, 1991). However, these two divisions also contain large numbers of genetically diverse strains. Other molecular techniques have provided a greater understanding of the infraspecific groupings of the pathogen.