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The antimicrobial peptide michiganin A was isolated from the tomato pathogen 'Clavibacter michiganensis' subsp. 'michiganensis' for purposes of purification and characterization. Michiganin A was seen to be a type B lantibiotic and cloning and sequencing of the gene additionally revealed the sequence of the atypical prepeptide of michiganin A.

Aims: Bacterial decays of onion bulbs have serious economic consequences for growers, but the aetiologies of these diseases are often unclear. We aimed to determine the role of Rahnella, which we commonly isolated from bulbs in the United States and Norway, in onion disease. Methods and Results: Isolated bacteria were identified by sequencing of housekeeping genes and/or fatty acid methyl ester analysis. A subset of Rahnella spp. strains was also assessed by multilocus sequence analysis (MLSA); most onion strains belonged to two clades that appear closely related to R. aquatilis. All tested strains from both countries caused mild symptoms in onion bulbs but not leaves. Polymerase chain reaction primers were designed and tested against strains from known species of Rahnella. Amplicons were produced from strains of R. aquatilis, R. victoriana, R. variigena, R. inusitata and R. bruchi, and from one of the two strains of R. woolbedingensis. Conclusions: Based on binational testing, strains of Rahnella are commonly associated with onions, and they are capable of causing mild symptoms in bulbs. Significance and Impact of the Study: While Rahnella strains are commonly found within field‐grown onions and they are able to cause mild symptoms, the economic impact of Rahnella‐associated symptoms remains unclear. [ABSTRACT FROM AUTHOR]

A survey of nematodes associated with terrestrial slugs was conducted for the first time in Norway. A total of 611 terrestrial slugs were collected from 32 sample sites. Slugs were identified by means of morphological examination, dissection of genitalia and molecular analysis using mitochondrial DNA. Twelve slug species were identified, representing four different slug families. Internal nematodes were identified by means of morphological analysis and the sequencing of the 18S rRNA gene. Of the sample sites studied, 62.5% were found to be positive for nematode parasites, with 18.7% of all slugs discovered being infected. Five nematode species were identified in this study: Alloionema appendiculatum, Agfa flexilis, Angiostoma limacis, Angiostoma sp. and Phasmarhabditis hermaphrodita. Of these species, only one nematode was previously undescribed (Angiostoma sp.). This is the first record of the presence of A. appendiculatum, A. flexilis and A. limacis in Norway. [ABSTRACT FROM AUTHOR]

Streptomyces scabies causes yield losses in potato by inducing common scab ( CS) symptoms on tubers. Little information is available on global gene expression responses in CS-causing streptomycetes upon interaction with host plants. In this study, expression of 8746 genes was analysed in the type strain of S. scabies ( ATCC49173) using a custom-designed, gene-specific oligonucleotide microarray. Bacteria were grown in liquid yeast malt extract ( YME) medium and 480 genes were found to be up-regulated 24 h after supplementing the cultures with potato microtubers. Quantitative PCR analysis of eight putative or known virulence genes was consistent with the microarray data. Elevated expression of the thaxtomin synthesis gene txtA and txtR genes regulating synthesis of thaxomin A, the main pathogenicity factor of S. scabies, and production of thaxtomin A were detected in cultures containing microtubers. Unexpectedly, thaxtomin was also detected in cultures lacking microtubers, which indicated that growth in YME induces thaxtomin production in S. scabies. Many but not all microtubers incubated in the cultures of S. scabies for 48 h displayed symptoms, indicating that the microtubers were not equally susceptible even though they were produced under uniform in vitro growth conditions. These factors may have limited the differences in gene expression observed between S. scabies exposed to microtubers compared to controls. This study provides some of the first results on the transcriptome of S. scabies, a widely distributed and important potato pathogen, upon exposure to young developing potato tubers. The findings will inform future studies on interactions of CS-inducing streptomycetes with potato and means to control the disease. [ABSTRACT FROM AUTHOR]