Simple and rapid detection of rice false smut pathogen Ustilaginoidea virens in rice seeds

A method for simple and rapid detection of Ustilaginoidea virens in rice seeds was developed based on specific polymerase chain reaction (PCR). To design the specific primers for detection of U. virens, the comparison was made on 5.8S rDNA intra- and inter-specific variations in nucleotide sequences of U. virens and other pathogens: Fusarium verticillioides, Sclerotinia sclerotiorum, Tilletia barclayana, Fusarium graminearum and Magnaporthe oryzae. A 346-bp fragment could be amplified by using the specific primers uvr-F and uvr-R in U. virens, but not in other test fungi, indicating that the designed primers were specific for the detection of U. virens. U. virens was detected in nine of the 24 tested rice samples, indicating that 37.5% of the rice samples were contaminated with the false smut pathogen. The development of the simple and rapid detection technique using specific primers will be applicable for direct identification of U. virens in rice seeds to screen large numbers of samples.