イネ白葉枯病菌繊維状ファージXfおよびXf2のDNA塩基組成は極めて類似している。それら両ファージの複製型DNA (RFI-DNA)を各種の制限酵素によって切断し,DNA断片の泳動パターンを比較し,両者の類縁の程度を検討した。RFI-DNAはファージ感染菌の溶菌液からエタノール沈殿により調製した。得られたRFIはイネ白葉枯病菌に対し感染性を有していた。Xf-RFIおよびXf2-RFIの分子量はアガロースゲル電気泳動の相対移動度より,それぞれ4.5×106および4.7×106ダルトンと推定された。両ファージのRF-Iを制限酵素Hpa II, Hha I, Hind II, Hae III, Alu Iで処理し,ポリアクリルアミドゲル電気泳動にかけた結果,得られた切断パターンには同一の泳動度を示す断片は極めて少なく,XfおよびXf2はかなり異なったファージであることが明らかとなった。
The effect of temperature on the inactivation of radish yellows pathogen (Fusarium oxysporum f. sp. raphani) during anaerobic fermentation of radish residues was examined. The debrises of diseased radish roots were anaerobically fermented under the different temperatures, by sealing up in plastic-film bags. Either at varying or constant temperature in the range from 10 to 30C, the higher the temperature, the faster the inactivation of the pathogen progressed. Inactivation of the pathogen occurred obviously with the progress of fermentation.
A virus was isolated from spinach plants showing rugose symptom in Saitama prefecture. The virus was readily transmitted by sap inoculation and by aphid, but not through seed of spinach. The virus had similar host range to CMV-P, although it did not produce any symptoms on tomato and cucumber. The virus was spherical particles, 30nm in diameter, and was serologically indistinguishable from CMV-P. Electrophoresis of RNA of the virus revealed four component showing minor differences in mobility from the components of CMV-Y and CMV-P. We propose the name of the virus, CMV-SR.
In 1982, a disease of strawberry plant, showing the symptoms of stunting and witches' broom, was observed in Shizuoka city. Electron microscopy revealed the presence of mycoplasmalike organisms (MLOs) in the sieve tubes of the diseased plants. Macrosteles orientalis, and Macrosteles fascifrons were found to transmit the disease to healthy plants. Of 29 species plants in 14 families, which were inoculated by the infectious M. orientalis, 26 species plants in 12 families were infected with the MLO. The strawberry witches' broom had a wide host range similar to those of sickle hare's ear yellows.
Rice sheath blight fungus, Rhizoctonia solani (IA), was isolated at the rate of 100% from the mature rice plants having many sheath blight lesions. However, from the diseased samples of sheath blight like lesions, Sclerotium oryzae-sativae was isolated at the rate of 70%. High isolation rate of S. hydrophilum was observed in the plants with many sheath blight lesions, but R. oryzae was detected more often in the plants with sheath blight like lesions. S. hydrophilum and S. oryzae-sativae were frequently isolated from lesions near the basal parts of the plants.