Rapid detection and quantification of Mycosphaerella graminicola in wheat using PCR and RT-PCR assays
Mycosphaerella graminicola is an economically important fungal disease in wheat. In this study, three PCR-based diagnostic assays were developed to qualitatively or quantitatively detect this pathogen in wheat using the four highly specific primer sets ST-rRNA F/R, ST-act F/R, R5870-1F/R5870-1R and R5870-1F/R5870-2R. To simplify the process of DNA or RNA extraction, three different procedures were improved. Their PCR conditions were optimized. Real-time PCR was successfully used to monitor the disease development in inoculated plants and naturally infected F, F1 and F2 leaves (F2 = third leaf from top to F = flag leaf) during the epidemic period. M. graminicola DNA could be detected on the inoculation day, and a clear growth tendency was obtained during the disease development. The DNA amounts were significantly correlated with the disease indice and the number of pycnidia. The efficacy of two fungicide treatments (Input and Fandango) on M. graminicola leaf blotch in different leaf positions were assessed using real-time PCR. Both treatments revealed high efficacy against M. graminicola leaf blotch. The Input treatment had better efficacy than the Fandango treatment. Three specific primer sets were successfully used for the RT-PCR assay. It was applied to follow the disease development in inoculated plants and in naturally infected F1 leaves using the primer set E1/STSP2R.