VIEW ARTICLE

Cytology and Histology

Scanning Electron Microscopy of the Infection Process of Rhizoctonia solani in Leaf Sheaths of Rice Plants. Kazuho Matsuura, Research Laboratories, Agricultural Chemicals Division, Takeda Chemical Industries Ltd., Kyoto 606, Japan; Phytopathology 76:811-814. Accepted for publication 7 January 1986. Copyright 1986 The American Phytopathological Society. DOI: 10.1094/Phyto-76-811.

Rhizoctonia solani, the causal fungus of sheath blight of rice plants, penetrates plants through the inner surfaces of leaf sheaths. The infection process of an isolate of R. solani was studied on the inner surfaces of leaf sheaths of rice plants. Hyphae from the inoculum grew upward and produced numerous side branches at the site 5-6 mm from the growing tips of mycelia. The side branches continued to proliferate in a localized area and resulted in infection cushions, which were closely appressed to the epidermis with mucilagelike material. Penetration from infection cushions was effected by slender infection pegs that developed from flattened cells at the base of the cushion. Numerous penetration pegs and pores were observed beneath the cushions. Multiple invasion from the epidermal cell lumen was observed. At the penetration site on the epidermis, the peg became slender, but it swelled and resumed normal diameter when it reached the cell lumen. The edges of the penetration pores on the epidermis were smooth.