A survey of the toxin production by several strains of blast fungus was carried out. Among the strains tested only one strain, C 1 (THU 69-03) produced a-picolinic acid with good yield and other strains produced neither a-picolinic acid nor piricularin. On the other hand, tenuazonic acid and its Fe-chelate compound were isolated as novel blast fungus toxins from the surface culture brothes of these strains, but they could not be isolated from the shaking culture brothes. The phytotoxic effect of tenuazonic acid on rice plants in regard to varietal difference was also studied.
Cell walls were prepared from Piricularia oryzae P2. Lytic enzymes were produced when Bacillus circulans WL 12 was grown with P. oryzae cell wall as a sole source of carbon. Mode of lysis of P. oryzae cell walls was compared with the lysis of walls of Aspergillus oryzae and Neurospora crassa. Activities of j3-1--~3-glucanase, chitinase, and (3-1->6-glucanase were demonstrated in the culture filtrate. Modes of lysis of cell walls of P. oryzae P2 by a single and combined action of lytic enzymes were compared. Combination of j3-1->3-glucanase and chitinase gave the most rapid and extensive lysis.Pathogenicity of Piricularia oryzae, a group of rice blast molds, has hitherto been studied in our laboratory primarily from the stand point of toxins, piricularin and picolinic acid, produced by the pathogens (1, 2).In order to expand the scope of our work on the host-parasite interactions, we recently started our work with cytological and biochemical approaches. Naturally, first contact between the host and the pathogen takes place at the surfaces of both organisms.We consider that the studies on the surface nature of P. oryzae and also of rice plants might give us some evidence which will help in our understanding of host-parasite interactions. Our understanding on the cell walls of fungi is still meager when compared with our knowledge on the walls of yeasts and bacteria.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.