Detection, quantification and characterization of Erwinia carotovora ssp. carotovora contaminating pepper seeds

Abstract

Erwinia carotovora ssp. carotovora (Ecc) was isolated from commercial pepper (Capsicum annuum) seed lots and identified according to biochemical and pathogenicity tests, cellular fatty acid composition, and PCR reaction with primers based on the pel gene sequence. RAPD-PCR analysis using nine arbitrary primers showed similarity between Ecc isolates obtained from pepper. Ecc isolates from pepper, tomato, potato and cabbage formed four distinct groups, according to the original host. A natural Ecc population higher than 100 CFU g-1 seed significantly affected seed germination. A significant correlation between the level of Ecc on the seeds and the percentage of diseased seedlings was also observed. Surface sterilization of the seeds with sodium hypochlorite eliminated the pathogen, indicating that the bacteria were located on the surface of the seeds. Contaminated pepper seeds can be a primary and important source of inoculum.