Appressorium-mediated penetration of Magnaporthe oryzae and Colletotrichum orbiculare into surface-cross-linked agar media.

Many phytopathogenic fungi form appressoria on some artificial substances. However, it is difficult to induce appressorium-mediated penetration into artificial substances. In the present study, novel artificial agar media were developed to investigate the in vitro penetration process of phytopathogenic fungi. The media contained sodium carboxymethyl cellulose or sodium alginate, and the surfaces were subjected to ionic cross-linking using trivalent metal ions. The hemibiotrophic phytopathogenic fungi, rice blast fungus and cucurbit anthracnose fungus, formed appressoria and penetrated into the surface cross-linked artificial agar media from the base of appressoria. These artificial media appeared to induce fungal infection behaviour that occurred on host plants.