Monoclonal antibodies (MAbs) specific to the 22-kDa coat protein (CP) of Broad bean wilt virus 2 (BBWV-2) were produced. The 22-kDa CP of the IA isolate expressed in E. coli was used to immunize mice and three independent hybridoma cell lines were screened. In western blot analyses, the MAbs (MAb3-9B, MAb5-12A and MAb6-2A) reacted to the bacterially expressed 22-kDa CP of the IA isolate and most BBWV-2 isolates, but not to some other BBWV-2 isolates and other plant viruses. In immuno-electron microscopy, MAb3-9B and MAb6-2A reacted with BBWV-2 particles to the 10-5 dilution.
In 2001, a new bacterial disease was observed on hydroponically cultured pak-choi [Brassica campestris L. (chinensis group)] in Fukushima Prefecture, Japan. Symptoms were expressed as water-soaked lesions that extended from the midrib to the tip of leaves. A causal bacterium was isolated not only from the infected tissues but also from the hydroponic solution. Stab inocula-tion of the midrib reproduced the original symptom. The symptom was also expressed after artificial inoculation of the roots, suggesting possible root infection from the bacterium in the hydroponic solution. The pathogen was identified as Xanthomonas campestris pv. campestris (Pammel 1895) Dowson 1939.
A rapid and simple procedure is described to detect the genomic RNA molecule of Cymbidium mosaic virus (CyMV). This method, named RT-LAMP, allows direct detection of RNA from infected plants without careful RNA extraction, rapid ther-mal cycling and gel electrophoresis. RT-LAMP was successfully used to detect CyMV from leaves of Phalaenopsis orchid in-fected with CyMV. A large amount of byproduct, pyrophospate ion, is produced, yielding a white precipitate of magnesium pyrophosphate in the reaction mixture. The presence or absence of this white precipitate allows easy detection of the amplifi-cation of CyMV genomic RNA without gel electrophoresis.
Mutants of Trichoderma sp. SKT-1 with tolerance to benomyl were easily induced with UV irradiation or nitrosoguanidine. Strain SKT-3 induced by UV irradiation possesses high tolerance to benomyl (MIC 1000μg/ml). Because it could be re-isolated on benomyl-containing culture media, activity of the strain could be tested in the environment, including soil and water systems. SKT-3 had suppressive activities against “Bakanae” disease and bacterial seedling blight comparable to its parent strain, SKT-1 and was compatible with benomyl-containing fungicides.
An outbreak of a new bacterial disease of flowering cabbage (Brassica oleracea var. acephala) was recorded in Hyogo (1999) and Shizuoka (2000) prefectures, which is characterized by dark brown leaf spots with gray center and yellow V-shaped lesions at the leaf margins. The pathogen was identified as Xanthomonas campestris pv. campestris (Pammel 1895) Dowson 1939. We propose the disease name as black rot of flowering cabbage.