Deoxyribonucleic Acid Relatedness Among Erwiniae and Other Enterobacteria: II. Corn Stalk Rot Bacterium and Pectobacterium chrysanthemi

Abstract

Relatedness of pectobacteria pathogenic to corn, grass, and sugar cane, and of isolates of Pectobacterium chrysanthemi pathogenic for chrysanthemum, dahlia, and dieffenbachia was determined by deoxyribonucleic acid (DNA) reassociation. Heterologous DNA preparations were allowed to reassociate. Thermal elution chromatography was used to separate reassociated nucleotide sequences from unreacted sequences and to determine the thermal stability of related sequences. DNA relatedness data indicate that corn stalk rot bacteria and strains pathogenic on grass are highly interrelated. Furthermore, strains of both types are distinct from Pectobacterium carotovorum and are most closely related to P. chrysanthemi. P. chrysanthemi strains fall into two relatedness groups, one of which contains isolates from chrysanthemum and guayule and the other isolates from dahlia or dieffenbachia. A sugar cane pathogen is 65% related to both the corn stalk rot bacteria and to strains of P. chrysanthemi. It is suggested that all of these organisms be considered as P. chrysanthemi and that the corn stalk rot and grass isolates be designated P. chrysanthemi pathovar zeae.