Abstract An immuno-capture PCR (IC-PCR) method for detection of Acidovorax avenae subsp. citrulli, a pathogen of bacterial fruit blotch of watermelon, has been established by combination of the ISE method with classical PCR and compared with the direct PCR method and growth-checking method. The results showed that all the strains of A. avenae subsp. citrulli tested produced 360bp specific fragments by the IC-PCR and direct PCR method, while others strains of 10 different genera showed negative PCR result. The minimum detection concentration for the IC-PCR and direct PCR method was about 50-102cfu/ml and 104cfu/ml, respectively. The sensitivity of the former is 100 times higher than that of later. Detection of 7 batches of different melon seeds from the markets by IC-PCR showed that 1 cantaloupe variety, 2 honey melon varieties and 2 watermelon varieties of seeds carried the pathogen which almost matched with the result of the growth-checking of the melon seeds. It indicates that the IC-PCR is accurate, sensitive, rapid and low cost.
