Growth of Ralstonia solanacearum strain OE1-1 in roots after invasion is required for virulence. An Arg740Cys substitution in sigma(70) of OE1-1 resulted in loss of in planta growth and virulence. The negative dominance of mutant sigma(70) over the wild-type protein suggested that the amino acid substitution may affect the in planta growth of OE1-1, leading to a lack of virulence.
