Bacillus spp. produce a broad spectrum of lipopeptide biosurfactants, among which surfactin, iturin and fengycin are widely studied families. The goals of this study were to characterize the biosurfactant activity of Bacillus spp. and to investigate their motility and biofilm formation capabilities. In addition, we extracted lipopeptides from these bacteria to assess their antifungal activities and analyzed these products by mass spectrometry (MS). B. amyloliquefaciens FZB42, Bacillus sp. NH 217 and B. subtilis NH-100 exhibited excellent biosurfactant and surface spreading activities, whereas B. atrophaeus 176s and Paenibacillus polymyxa C1225 showed moderate activity, and B. subtilis 168 showed no activity. Strains FZB42, NH-100, NH-217, 176s and CC125 exhibited excellent biofilm formation capabilities. Lipopeptide extracts displayed good antifungal activity against various phytopathogens and their associated diseases, such as Fusarium moniliforme (rice bakanae disease), Fusarium oxysporum (root rot), Fusarium solani (root rot) and Trichoderma atroviride (ear rot and root rot). Lipopeptide extracts of these strains also showed hemolytic activity, demonstrating their strong potential to produce surfactants. LCMS-ESI analyses identified the presence of surfactin, iturin and fengycin in the extracts of Bacillus strains. Thus, the strains assayed in this study show potential as biocontrol agents against various Fusarium and Trichoderma species.

Streptomycetes, typical soil dwellers, can be detected as common colonizers of human bodies, especially the skin, the respiratory tract, the guts and the genital tract using molecular techniques. However, their clinical manifestations and isolations are rare. Recently they were discussed as possible "coaches" of the human immune system in connection with certain immune disorders and cancer. This work aimed for the characterization and evaluation of genetic adaptations of a human-associated strain Streptomyces sp. TR1341. The strain was isolated from sputum of a senior male patient with a history of lung and kidney TB, recurrent respiratory infections and COPD. It manifested remarkably broad biological activities (antibacterial, antifungal, betahemolytic, etc.). We found that, by producing specific secondary metabolites, it is able to modulate host immune responses and the niche itself, which increase its chances for long-term survival in the human tissue. The work shows possible adaptations or predispositions of formerly soil microorganism to survive in human tissue successfully. The strain produces two structural groups of cytotoxic compounds: 28-carbon cytolytic polyenes of the filipin type and actinomycin X2. Additionally, we summarize and present data about streptomycete-related human infections known so far.

Background and Aims Laboratory and greenhouse experiments have shown that root-associated bacteria have beneficial effects on grapevine growth; however, these effects have not been tested in the field. Here, we aimed to demonstrate whether bacteria of different geographical origins derived from different crop plants can colonize grapevine to gain a beneficial outcome for the plant leading to promote growth at the field scale. Methods To link the ecological functions of bacteria to the promotion of plant growth, we sorted fifteen bacterial strains from a larger isolate collection to study in vitro Plant Growth Promoting (PGP) traits. We analysed the ability of these strains to colonise the root tissues of grapevine and Arabidopsis using greenfluorescent-protein-labelled strain derivatives and a cultivation independent approach. We assessed the ability of two subsets randomly chosen from the 15 selected strains to promote grapevine growth in two field-scale experiments in north and central Italy over two years. Parameters of plant vigour were measured during the vegetative season in de novo grafted vine cuttings and adult productive plants inoculated with the bacterial strains. Results Beneficial bacteria rapidly and intimately colonized the rhizoplane and the root system of grapevine. In the field, plants inoculated with bacteria isolated from grapevine roots out-performed untreated plants. In both the tested vineyards, bacteria-promotion effects largely rely in the formation of an extended epigeal system endowed of longer shoots with larger diameters and more nodes than non-inoculated plants.Conclusions PGP bacteria isolated in the laboratory can be successfully used to promote growth of grapevines in the field. The resulting larger canopy potentially increased the photosynthetic surface of the grapevine, promoting growth.

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Microbacterium species have been isolated from a wide range of hosts and environments, including heavy metal-contaminated sites. Here, we present a comprehensive analysis on the phylogenetic distribution and the genetic potential of 70 Microbacterium belonging to 20 different species isolated from heavy metal-contaminated and non-contaminated sites with particular attention to secondary metabolites gene clusters. The analyzed Microbacterium species are divided in three main functional clades. They share a small core genome (331 gene families covering basic functions) pointing to high genetic diversity. The most common secondary metabolite gene clusters encode pathways for the production of terpenoids, type III polyketide synthases and non-ribosomal peptide synthetases, potentially responsible of the synthesis of siderophore-like compounds. In vitro tests showed that many Microbacterium strains produce siderophores, ACC deaminase, auxins (IAA) and are able to solubilize phosphate. Microbacterium isolates from heavy metal contaminated sites are on average more resistant to heavy metals and harbor more genes related to metal homeostasis (e.g., metalloregulators). On the other hand, the ability to increase the metal mobility in a contaminated soil through the secretion of specific molecules seems to be widespread among all. Despite the widespread capacity of strains to mobilize several metals, plants inoculated with selected Microbacterium isolates showed only slightly increased iron concentrations, whereas concentrations of zinc, cadmium and lead were decreased.

A Gram-reaction-positive, motile, yellow-pigmented and rod-shaped bacterial strain, designated AR33T, was isolated from the rhizosphere of Salix caprea L. growing in a former zinc/lead mining and processing site in Austria. A polyphasic approach was applied to determine its taxonomic position. 16S rRNA gene sequence analysis, and morphological and chemotaxonomic properties showed that strain AR33T belongs to the genus Agromyces. Strain AR33T had peptidoglycan type B2γ and the major menaquinones were MK-11, MK-10 and MK-12. The main branched-chain fatty acids were anteiso-C15 : 0, anteiso-C17 : 0 and iso-C16 : 0. Strain AR33T showed catalase and oxidase activity and multiple heavy metal resistances to zinc, lead and cadmium. The DNA G+C content was 70.1 mol%. Levels of 16S rRNA gene sequence similarity with closely related recognized species of the genus Agromyces ranged between 98 and 99 %. However, DNA-DNA hybridization between strain AR33T and the type strains of three Agromyces species showed values lower than 42 % relatedness. Therefore, differential phenotypic characteristics together with DNA-DNA relatedness suggested that strain AR33T can be recognized as representing a distinct Agromyces species, for which the name Agromyces aureus sp. nov. is proposed. The type strain is AR33T (=DSM 101731T=LMG 29235T).

Wolbachia is a highly successful endosymbiont that can manipulate host reproduction to ensure efficient vertical transmission from mother to offspring (Werren et al., 2008). Cytoplasmic incompatibility (CI) is the most common form of reproductive manipulation, where crosses between uninfected females and infected males result in embryonic death of offspring. However, if an infected male

Hemipteran insects are well-known for their ancient associations with beneficial bacterial endosymbionts, particularly nutritional symbionts providing the host with essential nutrients such as amino acids or vitamins lacking from the host’s diet. Thereby, these primary endosymbionts enable the exploitation of nutrient-poor food sources such as plant sap or vertebrate blood. In turn, the strictly host-associated lifestyle strongly impacts the genome evolution of the endosymbionts, resulting in small and degraded genomes. Over time, even the essential nutritional functions can be compromised, leading to the complementation or replacement of an ancient endosymbiont by another, more functionally versatile, bacterium. Herein, we provide evidence for a dual primary endosymbiosis in several psyllid species. Using metagenome sequencing, we produced the complete genome sequences of both the primary endosymbiont ‘CandidatusCarsonella ruddii’ and an as yet uncharacterizedEnterobacteriaceaebacterium from four species of the genusCacopsylla. The latter represents a new psyllid-associated endosymbiont clade for which we propose the name ‘CandidatusPsyllophila symbiotica’. Fluorescentin situhybridisation confirmed the co-localization of both endosymbionts in the bacteriome. The metabolic repertoire ofPsyllophilais highly conserved across host species and complements the tryptophan biosynthesis pathway that is incomplete in the co-occurringCarsonella. Unlike co-primary endosymbionts in other insects, the genome ofPsyllophilais almost as small as the one ofCarsonella, indicating an ancient co-obligate endosymbiosis rather than a recent association to rescue a degrading primary endosymbiont.