Pathogenicity shown in three distinct Magnaporthe oryzae isolates

Abstract

To further understand the pathogenesis of blast disease in rice, three isolates of Magnaporthe were examined in this work. Under controlled laboratory conditions, M. oryzae 6808 and M. oryzae ch1 isolates generated appressoria and macroconidia with pyriform shapes. In the same environment, M. oryzae 6926 did not develop appressoria but did produce crescent-shaped microconidia. All three of the Magnaporthe isolates tested positive in the pathogen inoculation assay, but to different degrees. Different cultivars of paddy lines showed varying degrees of disease severity as a result of pathogen isolates producing spindle-shaped lesions with necrotic margins. In rice lines, both forms of sporulation increased the frequency and severity of illness. A lot of research has focused on the process of pyriform macroconidia entering a suitable host plant and developing appressoria. In order for crescent-shaped microconidia to infect plants that are a good fit, they will need to find another way to enter host cells. Both macroconidia and microconidia were shown to produce pathogenicity in rice. The role of microconidial infection in the progression of blast illness requires more research.