detection of rice blast pathogens: expedition from petriplate to PCR tube- a mini review

Abstract

Rice blast caused by Magnaporthe oryzae (anamorph: Pyricularia oryzae) is a serious disease of rice threatening its production worldwide. The pathogen has high genomic plasticity, wide host range and rapid rate of evolution resulting in fungicidal resistance and breakdown of resistant varieties. Though integrated disease management modules have been adopted for the management of the pathogen, the disease continues to be a challenge to plant pathologists. The pathogen affects all the above-ground parts of the plant including seeds. Seeds are implicated as important overwintering source of inoculum of the pathogen and may serve as an important source of primary inoculum during the rice season. Further, the spread of pathogen to previously un- invaded areas has been found associated with the movement of the infected seeds. Therefore, use of pathogen-free healthy seeds should be an integral part of the rice blast management module, for quarantine purposes. Further, with the appearance of wheat blast as a global threat to wheat production and invasion of rice blast pathogen to previously uninvaded areas, accurate detection of M. oryzae strains is of paramount importance. Conventionally used seed testing assays are time-consuming, labor-intensive and have low sensitivity and specificity. Advances in the detection strategies of rice blast pathogen from blotter test to high throughput real time PCR is remarkable. But still, commercial application of these technologies is lacking. The review focuses on the advances in detection strategies of M. oryaze and their utility as commercial protocols.