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Lytic bacteriophages able to infect and killDickeyaspp. can be readily isolated from virtually allDickeyaspp.-containing environments, yet little is known about the selective pressure those viruses exert on their hosts. Here, we identified two spontaneousD. solaniIPO 2222 mutants (0.8% of all obtained mutants), DsR34 and DsR207, resistant to infection caused by lytic phage vB_Dsol_D5 (ΦD5) that expressed a reduced ability to macerate potato tuber tissues compared to the wild-type, phage-susceptibleD. solaniIPO 2222 strain. Genome sequencing revealed that genes encoding: secretion protein HlyD (mutant DsR34) and elongation factor Tu (EF-Tu) (mutant DsR207) were altered in these strains. Both mutations impacted the proteomes of cells grown in both rich and minimal media, including the abundance of the cell envelope and transmembrane transport-associated proteins. Furthermore, features essential for the ecological success of these mutants in a plant environment, including their ability to use various carbon and nitrogen sources, produce plant cell wall degrading enzymes, ability to form biofilms, siderophore production, swimming and swarming motility and virulencein plantawere assessed. Compared to the wild-type strain,D. solanistrain IPO 2222, mutants DsR34 and DsR207 had a reduced ability to macerate chicory leaves and to colonize and cause symptoms in growing potato plants. The implications of the ΦD5 resistance on driving traits affecting the ecological performance ofD. solaniare discussed.

Resistance to bacteriophage infections protects bacteria in phage-full environments, allowing them to survive and multiply in the presence of their viral predators. However, such resistance may cause direct costs for strains linked with the ecological fitness expressed as reduced competitiveness for resources or reduced virulence or both. Unfortunately, limited knowledge exists about such costs paid by phage-resistant plant pathogenic bacteria in their natural environments. This study analyzed the costs of phage resistance paid by broad host phytopathogenic pectinolytic bacterium Dickeya solani both in vitro and in potato (Solanum tuberosum L.) plants. Thirteen D. solani IPO 2222 Tn5 mutants were identified that exhibited resistance to infection caused by lytic bacteriophage vB_Dsol_D5 (ΦD5). The genes disrupted in these 13 mutants encoded proteins involved in the synthesis of the bacterial envelope components (viz. LPS, EPS and capsule). The ability of ΦD5-resistant D. solani mutants to colonize and cause symptoms on potato plants as well as other phenotypes that are known to contribute to the ecological fitness of D. solani in-plant environment, including growth rate, production of effectors, swimming and swarming motility, use of various carbon and nitrogen sources and biofilm formation were assessed. Although phage resistance did not affect most of the phenotypes of ΦD5-resistant D. solani evaluated in vitro, all phage resistant mutants were significantly compromised in their ability to survive on and colonize and cause disease symptoms in potato plants. This study is, to our knowledge, one of few to show the direct link between phage resistance and the fitness of plant pathogenic bacteria and the first one to assess phage-host associations for D. solani.

Strain P482 was isolated from a tomato rhizosphere and classified as Pseudomonas donghuensis. The P. donghuensis species was first established in 2015 and currently consists of only four strains: P482, HYST, SVBP6, and 22G5. P. donghuensis strains antagonize plant pathogens, including bacteria, fungi, and oomycetes, and, therefore, are of high interest regarding their biological control potential to combat plant diseases. The antimicrobial activity of P. donghuensis P482 is based on the production of iron-scavenging compound 7-hydroxytropolone, antifungal volatile organic compounds, and as-yet-unidentified secondary metabolites. Here, we report a complete genome resource for P. donghuensis strain P482. The genome consists of a single chromosome (5,656,185 bp) with 5,258 open reading frames (5,158 protein-coding genes, 74 transfer RNAs, 22 ribosomal RNAs, 3 noncoding RNAs, and 1 transfer-messenger RNA) and no plasmid. We believe that information on the first high-quality, complete genome of P. donghuensis will provide resources for analyses targeting the biological control potential of this species and understanding the traits essential for plant–microbe interaction. [Formula: see text] Copyright © 2021 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license .

Pectobacterium atrosepticumis a narrow host range pectinolytic plant pathogenic bacterium causing blackleg of potato (Solanum tuberosumL.) worldwide. Till present, severalP. atrosepticumgenomes have been sequenced and characterized in detail; all of these genomes have come, however, fromP. atrosepticumstrains isolates from plants grown in temperate zones, not from hosts cultivated under different climatic conditions. Herewith, we present the first complete, high-quality genome of theP. atrosepticumstrain Green1 isolated from potato plants grown under subarctic climate in Greenland. The genome ofP. atrosepticumstrain Green1 consists of one chromosome of 4,959,719 bp., with a GC content of 51% and no plasmids. The genome contains 4531 annotated features, including 4179 protein-coding genes (CDSs), 22 rRNA genes, 70 tRNA genes, 8 ncRNA genes, 2 CRISPRs and 126 pseudogenes. We believe that the information of this first, high-quality, complete, closed genome ofP. atrosepticumstrain isolated from host plant grown in subarctic agricultural region will provide resources for comparative genomic studies and for analyses targeting climatic adaptation and ecological fitness mechanisms present inP. atrosepticum.

Dickeya solani is an emerging plant pathogenic bacterium, causing disease symptoms in a variety of agriculturally relevant crop species worldwide. To date a number of D. solani genomes have been sequenced and characterized, the great majority of these genomes have however come from D. solani strains isolated from potato (Solanum tuberosum L.) and not from other plant hosts. Herewith, we present the first complete, high-quality genome of D. solani strain IPO 2019 (LMG 25990) isolated from ornamental plant Hyacinthus orientalis. The genome of D. solani strain IPO 2019 consists of one chromosome of 4,919,542 bp., with a GC content of 56.2% and no plasmids. The genome contains 4502 annotated features, 22 rRNA genes, 73 tRNA genes and 1 CRISPRS. We believe that the information of this high-quality, complete, closed genome of D. solani strain isolated from host plant different than potato (i.e. hyacinth) will provide resources for comparative genomic studies as well as for analyses targeting adaptation and ecological fitness mechanisms present in Dickeya solani species.