Molecular Detection of Magnaporthe oryzae from Rice Seeds

Rice blast disease caused by the fungus Magnaporthe oryzae is one of the most devastating diseases of rice worldwide. Blast pathogen infects all stages of rice causing leaf, collar, neck, and panicle blast symptoms. Seedlings infested by M. oryzae serve as an inoculum source, which gradually causes the disease symptoms on rice leaves. Hence, for the blast disease management, it is crucial to detect the pathogen in rice seeds, particularly at the presymptomatic stage. Early pathogen diagnosis enhances the accuracy and timing of fungicide applications, thereby improving their efficiency. Moreover, detection of infested seeds is important for the quarantine purposes to ensure the flow of quality rice seeds to the market. In this chapter, a PCR-based assay is described to detect the blast pathogen from rice seeds. The ability of this molecular method in reliably detecting pathogens can prevent the spread of blast disease because of its increased sensitivity and the reduction of diagnostic time.