Detection of Acidovorax citrulli by Co-operational Polymerase Chain Reaction for Seed Health Testing of Watermelon Seed

Abstract

The bacterial fruit blotch (BFB) caused by Acidovorax citrulli is a serious pathogen for cucurbits seed production. This bacterium is a seed-borne and seed-transmitted pathogen with long-term survival in seeds. Contaminated seeds are an important source of primary inoculum for the spreading of BFB disease in seed beds. Detection technique for the pathogen which is reliable, effective, sensitive and specific is an important tool for controlling seed quality in both local and international seed trade. The Co-PCR was shown to be effective in detecting A. citrulli in the artificially inoculated watermelon seeds by seed soaking. The samples were prepared by filtering the seed soaking liquid using bacterial ltration system then extracted the bacterium DNA from the filtered remain and used as the target DNA. Results indicated that this procedure could detect A. citrulli presented at the level of 103 CFU/seed in an artificially inoculated watermelon seed stocks which had 0.05% and 0.01% infestation rates. It could also detect the bacterium in naturally infected watermelon seeds.