Rapid Identification of Corynespora cassiicola by multiplex PCR

The target leaf spot, an end-of-cycle disease that can cause soybean losses of 40%, is caused by the fungus Corynespora cassiicola. The aim of this study was to devise and validate a multiplex PCR protocol for the molecular identification of C. cassiicola, in both pure cultures of isolates and plants. For the analysis, a total of 75 samples was evaluated been 57 possible fungal isolates of C. cassiicola and 18 soybean plants displaying symptoms associated with target leaf spot. Total DNA was extracted from the pure cultures of the isolates and of four symptomatic leaf discs taken from each of the plants soybean evaluated and submitted to the conventional multiplex PCR technique using two primer pairs: ITS-1/ITS-4 and GA4-F/GA4-R. The ideal conditions for multiplex PCR were adjusted. The 57 isolates identified as C. cassiicola and among the evaluated plants, 15 samples were infected. Conventional multiplex PCR is efficient at identifying Corynespora cassiicola isolates and for rapid diagnosis of infected plants.