Here we report the complete sequence of the mitochondrial (mt) genome of the necrotrophic phytopathogenic fungus Sclerotinia borealis, a member of the order Helotiales of Ascomycetes. The 203,051 bp long mtDNA of S. borealis represents one of the largest sequenced fungal mt genomes. The large size is mostly determined by the presence of mobile genetic elements, which include 61 introns. Introns contain a total of 125,394 bp, are scattered throughout the genome, and are found in 12 protein-coding genes and in the ribosomal RNA genes. Most introns contain complete or truncated ORFs that are related to homing endonucleases of the LAGLIDADG and GIY-YIG families. Integrations of mobile elements are also evidenced by the presence of two regions similar to fragments of inverton-like plasmids. Although duplications of some short genome regions, resulting in the appearance of truncated extra copies of genes, did occur, we found no evidences of extensive accumulation of repeat sequences accounting for mitochondrial genome size expansion in some other fungi. Comparisons of mtDNA of S. borealis with other members of the order Helotiales reveal considerable gene order conservation and a dynamic pattern of intron acquisition and loss during evolution. Our data are consistent with the hypothesis that horizontal DNA transfer has played a significant role in the evolution and size expansion of the S. borealis mt genome.

2016-12-24T18:07:49

We review the potential for related soya species to cross-pollinate in field and greenhouse conditions. Several local soybean cultivars were fertilized successfully by pollen from wild soya. However, when the GM soybean cv. Stine 2254 RR (GTS 40-3-2) was used as a pollen 'donor' and plants of Glycine soja were the pollen 'trap', no herbicide-resistant plants were obtained during two growing seasons. Thus, natural cross-pollination between plants of the soybean species would probably be extremely rare, with a frequency below the sensitivity of this experiment. More data are needed to evaluate fully the extent of transfer of herbicide tolerance genes from widespread cultivation of soybeans to wild soya that might occur in this region.

We report here the annotated genome sequence of Xanthomonas arboricola strain 3004, isolated from barley leaves with symptoms of streak and capable of infecting other plant species. We sequenced the genome of X. arboricola strain 3004 to improve the understanding of molecular mechanisms of the pathogenesis and evolution of the genus Xanthomonas.

Soft rot caused by numerous species of Pectobacterium and Dickeya is a serious threat to the world production of potatoes. The application of bacteriophages to combat bacterial infections in medicine, agriculture, and the food industry requires the selection of comprehensively studied lytic phages and the knowledge of their infection mechanism for more rational composition of therapeutic cocktails. We present the study of two bacteriophages, infective for the Pectobacterium brasiliense strain F152. Podoviridae PP99 is a representative of the genus Zindervirus, and Myoviridae PP101 belongs to the still unclassified genomic group. The structure of O-polysaccharide of F152 was established by sugar analysis and 1D and 2D NMR spectroscopy:The recombinant tail spike protein of phage PP99, gp55, was shown to deacetylate the side chain talose residue of bacterial O-polysaccharide, thus providing the selective attachment of the phage to the cell surface. Both phages demonstrate lytic behavior, thus being prospective for therapeutic purposes.

Novel primers for rep-PCR were developed with the original software and based on 'ancient diverged periodical sequences'. Rep-PCR with these primers was applied to study genetic relationships among 51 Xanthomonas campestris strains. The strains were collected from different countries including Russia, Japan, UK, Germany and Hungary. Reference strains of three X. campestris pathovars and five other Xanthomonas species were included. Based on qualitative differences in amplification profiles, the strains were divided into four major groups. Two subgroups recognised within X. campestris population were similar to RFLP haplotypes. The third subgroup included strains of two other pathovariants and Japanese isolates of X. campestris pv. campestris while the fourth group comprised the other species of Xanthomonas. The analysis of the diversity within X. campestris resulted in the conclusion that isolates belong to distinct clonal populations (subgroups). The differences between the subgroups of X. campestris were only slightly smaller than between species of Xanthomonas. A PCR fragment about 600 bp amplified by primer KRPN2 was found in nearly all tested strains of X. campestris. SCAR primers designed for this marker produced a single specific band for strains of X. campestris, but not for other Xanthomonas, Pseudomonas and Erwinia strains tested. Application of the new primer set for rep-PCR offers a rapid, simple and reproducible method for identification of bacterial strains. The X. campestris-specific SCAR primers may be used in diagnostics of this important plant pathogen.

Phytopathogenic bacteria belonging to the Pectobacterium and Dickeya genera (soft-rot Pectobacteriaceae) are in the focus of agriculture-related microbiology because of their diversity, their substantial negative impact on the production of potatoes and vegetables, and the prospects of bacteriophage applications for disease control. Because of numerous amendments in the taxonomy of P. carotovorum, there are still a few studied sequenced strains among this species. The present work reports on the isolation and characterization of the phage infectious to the type strain of P. carotovorum. The phage Arno 160 is a lytic Podovirus representing a potential new genus of the subfamily Autographivirinae. It recognizes O-polysaccahride of the host strain and depolymerizes it in the process of infection using a rhamnosidase hydrolytic mechanism. Despite the narrow host range of this phage, it is suitable for phage control application.

Dickeya solani is a recently emerged virulent bacterial potato pathogen that poses a major threat to world agriculture. Because of increasing antibiotic resistance and growing limitations in antibiotic use, alternative antibacterials such as bacteriophages are being developed. Myoviridae bacteriophages recently re-ranked as a separate Ackermannviridae family, such as phage PP35 described in this work, are the attractive candidates for this bacterial biocontrol. PP35 has a very specific host range due to the presence of tail spike protein PP35 gp156, which can depolymerize the O-polysaccharide (OPS) of D. solani. The D. solani OPS structure, →2)-β-D-6-deoxy-D-altrose-(1→, is so far unique among soft-rot Pectobacteriaceae, though it may exist in non-virulent environmental Enterobacteriaceae. The phage tail spike depolymerase degrades the shielding polysaccharide, and launches the cell infection process. We hypothesize that non-pathogenic commensal bacteria may maintain the population of the phage in soil environment.