Development of Loop-Mediated Isothermal Amplification for Detection ofLeifsonia xylisubsp.xyliin Sugarcane

Ratoon stunt, caused by the xylem-limited coryneform bacteriumLeifsonia xylisubsp.xyli(Lxx), is a deep bacteriosis and prevalent in most of sugarcane-producing countries. Based on loop-mediated isothermal amplification (LAMP), we developed a method for detectingLxx. The major advantages of the LAMP method are visual judgment by color and time saving with only 60 min for identification ofLxxand without the need for costly PCR apparatus and gel scanner. In the present study, positive and negative samples detected by the LAMP method were clearly distinguishable. When total DNA extracted from internode juice was used as the template, the sensitivity of LAMP was 10 times higher than that of the conventional PCR detection. The LAMP assay is a highly specific, rapid, and sensitive method for the diagnosis of ratoon stunt caused byLxxin sugarcane. This is the first report of LAMP-based assay for the detection ofLxxin sugarcane.

Actinomyces hominis sp. nov., isolated from a wound swab

A coryneform bacterium (strain 1094T) was isolated from a wound swab taken from an 89-year-old female patient. Chemotaxonomic investigations suggested that this bacterium was related to the genera Actinomyces, Arcanobacterium and Actinobaculum. Phylogenetic analysis of 16S rRNA gene sequences showed that strain 1094T was most closely related to Actinomyces europaeus CCUG 32789 AT (94.3 % similarity). Phenotypically, the isolate could be separated from its closest phylogenetic neighbours on the basis of being positive for catalase, CAMP reaction, acid phosphatase, N-acetyl-β-glucosaminidase and raffinose fermentation. Based on the data presented, it is proposed that strain 1094T should be classified in a novel species, Actinomyces hominis sp. nov. The type strain is 1094T (=CCUG 57540T =DSM 22168T).