qPCR-based detection of Colletotrichum truncatum in soybean seeds

Soybean seed infected with Colletotrichum truncatum is an important source of primary inoculum for anthracnose epidemics. Based on differences in the GAPDH gene sequences of Colletotrichum species, one pair of species-specific primers, CtruncF1/CtruncR1, was designed to accurately detect C. truncatum in soybean seed samples. The primers amplified only a single PCR band of 211 bp from C. 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/μL of C. truncatum DNA 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.