qPCR-based detection ofColletotrichum truncatumin soybean seeds

Soybean seed infected withColletotrichum truncatumis an important source of primary inoculum for anthracnose epidemics. Based on differences in theGAPDHgene sequences ofColletotrichumspecies, one pair of species-specific primers, CtruncF1/CtruncR1, was designed to accurately detectC. truncatumin soybean seed samples. The primers amplified only a single PCR band of 211 bp fromC. truncatum. SYBR Green qPCR using these primers enabled the detection of DNA of the target fungus in inoculated soybean seeds and in naturally infested seeds. The sensitivity of the method was 0.000253 ng/mu L ofC. truncatumDNA template, with an efficiency of 1.78 and a Ct of 30.09. These species-specific primers may be useful for certification of soybean seeds aimed at avoiding introduction of the pathogen into soybean-producing regions.