Seven toxic substances to rice seedlings were isolated from the cultured cell suspension of X. campestris pv. oryzae and they were identified as 3-methylthiopropionic acid, trans-3-methylthioacrylic acid, phenylacetic acid, isovaleric acid, tiglic acid, succinic acid and fumaric acid by means of UV-, IR-, NMR- and Mass-spectroscopy and of elementary analysis.
Mosaic plants of perilla were collected in Tokyo and Saitama prefecture. Virus particles detected in the diseased leaves were flexuous rods, about 13×760nm, with a helical symmetry of 3.4nm pitch. In ultrathin sections of the diseased leaves, the virus particles and cytoplasmic inclusions such as pinwheels and bundles were observed in the cytoplasm of virus-infected cells. By sap inoculation, the virus produced chlorotic local lesions on Chenopodium amaranticolor, C. quinoa, Gomphrena globosa, and Vicia faba, while it produced systemic mottling on Perilla frutescens var. acuta. The virus was also transmitted in a non-persistent manner by Myzus persicae (Sulz.). The virus was tentatively named perilla mottle virus.
One isolate (Naga 64-8) among rice blast fungi (Pyricularia oryzae Cavara) isolated in Japan formed a very few susceptible lesions on Milyang 23 and Yushin of the Tongil variety group of Korean rice. All the reisolates from their lesions were severely pathogenic against the two Tongil varieties. On the other hand, reisolates from the lesions on Japanease rice varieties inoulated by the isolate of Naga 64-8 and those from the spores of the isolate on an oat-meal decoction agar medium contained both the pathogenic and the nonpathogenic isolates against the Tongil varieties. All their isolates showed the same reactions to the Japanease differentials as the isolate of Naga 64-8. The above results showed that the mother isolate of Naga 64-8 (033) contained two types of spores differing in pathogenicity against the Tongil varieties. Thus, we presumed that the isolate pathogenic against the Tongil varieties might sort out during successive culturing of the fungus by mutation.