After tomato plants were inoculated with an attenuated isolate CM95 of Cucumber mosaic virus (CMV), a promising biocontrol agent for CMV, either the number or weight of marketable fruits was reduced when a basal level of fertilizer was added to rock wool or soil culture in aphid-proof plastic houses. However, increasing the amount of fertilizer when applied as a solution or side dressing hardly reduced yield while significantly increasing vitamin C in tomato fruits.
紫外線で検出可能な放線菌の二次代謝産物を指標としたジャガイモそうか病菌の簡易迅速識別を試みた.Bennett寒天平板培地で3種のジャガイモそうか病菌Streptomyces scabies, S. acidiscabies, S. turgidiscabiesをそれぞれ25°Cで5日間培養後,菌叢を寒天ごと3∼5mm角に切り出し,ガラス製管瓶中で有機溶媒により二次代謝産物の抽出を行った.抽出溶媒として用いたメタノール-ジエチルエーテル(2:1, v/v),メタノール,アセトニトリルのなかでは,精度,簡便さ,迅速性の点でアセトニトリルが最も適していた.アセトニトリル抽出物をシリカゲル薄層プレートにスポットし,クロロフォルム-メタノール-アセトン-酢酸-水(55:20:4:4:2, v/v)を用い,25°C, 90分間展開後,暗所において紫外線(波長365nm)を照射して観察した.得られたスポットパターンから3種のジャガイモそうか病菌は明確に識別され,本法はジャガイモそうか病菌の簡易迅速識別法として有用であることが示された.
The method of Goto and Yamanaka (1968) was modified to improve efficiency when differentiating of Pyricularia grisea races. Three seeds of one of each of 12 Japanese differential rice varieties were sown in a 3-cm square cell of a 12-cell tray (3×4 cell) and treated immediately with 10ml of 2.5μg/ml uniconazole (a plant growth regulator) to yield dwarf seedlings. The seedlings (5-leaf stage) were then inoculated with one of 23 blast isolates (6 races), and covered with plastic cases to prevent contamination from the other isolates. The blast races identified by the method were consistent with those identified with the method of Goto and Yamanaka. With the use of dwarf seedlings and protection cases, many blast isolates can be identified at the same time.
Ustilaginoidea virens, which causes false smut of rice, on panicles of rice cultivar Toride 1 cultivated in the field was detected before and after heading using a nested-PCR technique with a two-species-specific primer set. The fungus was detected in rice panicles in both inoculated and noninoculated plots at the booting stage, although the frequency of the detection tended to be less than that detected at first and full heading. This technique is effective for detecting the fungus, and the panicles were found to be infected with the fungus before heading.
A new bacterial wilt was found on balsam pear (Momordica charantia L.) in Okinawa, Japan in October 1999. The causal bacterium was identified by its bacteriological characteristics as Ralstonia solanacearum, and the name “bacterial wilt” was proposed for the disease.