Correction: Qualitative analysis of biosurfactants from Bacillus species exhibiting antifungal activity.

[This corrects the article DOI: 10.1371/journal.pone.0198107.]

Seasonal wild dance of dual endosymbionts in the pear psyllid Cacopsylla pyricola (Hemiptera: Psylloidea)

Abstract Most sap-feeding insects maintain obligate relationships with endosymbiotic bacteria that provide their hosts with essential nutrients. However, knowledge about the dynamics of endosymbiont titers across seasons in natural host populations is scarce. Here, we used quantitative PCR to investigate the seasonal dynamics of the dual endosymbionts “Candidatus Carsonella ruddii” and “Ca. Psyllophila symbiotica” in a natural population of the pear psyllid Cacopsylla pyricola (Hemiptera: Psylloidea: Psyllidae). Psyllid individuals were collected across an entire year, covering both summer and overwintering generations. Immatures harboured the highest titers of both endosymbionts, while the lowest endosymbiont density was observed in males. The density of Carsonella remained high and relatively stable across the vegetative period of the pear trees, but significantly dropped during the non-vegetative period, overlapping with C. pyricola’s reproductive diapause. In contrast, the titer of Psyllophila was consistently higher than Carsonella’s and exhibited fluctuations throughout the sampling year, which might be related to host age. Despite a tightly integrated metabolic complementarity between Carsonella and Psyllophila, our findings highlight differences in their density dynamics throughout the year, that might be linked to their metabolic roles at different life stages of the host

Comparative genome sequencing reveals insights into the dynamics of Wolbachia in native and invasive cherry fruit flies

Wolbachia is a maternally inherited obligate endosymbiont that can induce a wide spectrum of effects in its host, ranging from mutualism to reproductive parasitism. At the genomic level, recombination within and between strains, transposable elements, and horizontal transfer of strains between host species make Wolbachia an evolutionarily dynamic bacterial system. The invasive cherry fruit fly Rhagoletis cingulata arrived in Europe from North America similar to 40 years ago, where it now co-occurs with the native cherry pest R. cerasi. This shared distribution has been proposed to have led to the horizontal transfer of different Wolbachia strains between the two species. To better understand transmission dynamics, we performed a comparative genome study of the strain wCin2 in its native United States and invasive European populations of R. cingulata with wCer2 in European R. cerasi. Previous multilocus sequence genotyping (MLST) of six genes implied that the source of wCer2 in R. cerasi was wCin2 from R. cingulata. However, we report genomic evidence discounting the recent horizontal transfer hypothesis for the origin of wCer2. Despite near identical sequences for the MLST markers, substantial sequence differences for other loci were found between wCer2 and wCin2, as well as structural rearrangements, and differences in prophage, repetitive element, gene content, and cytoplasmic incompatibility inducing genes. Our study highlights the need for whole-genome sequencing rather than relying on MLST markers for resolving Wolbachia strains and assessing their evolutionary dynamics

Qualitative analysis of biosurfactants from <i>Bacillus</i> species exhibiting antifungal activity

<div><p><i>Bacillus</i> 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 <i>Bacillus</i> 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). <i>B</i>. <i>amyloliquefaciens</i> FZB42, <i>Bacillus</i> sp. NH 217 and <i>B</i>. <i>subtilis</i> NH-100 exhibited excellent biosurfactant and surface spreading activities, whereas <i>B</i>. <i>atrophaeus</i> 176s and <i>Paenibacillus polymyxa</i> C1225 showed moderate activity, and <i>B</i>. <i>subtilis</i> 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 <i>Fusarium moniliforme</i> (rice bakanae disease), <i>Fusarium oxysporum</i> (root rot), <i>Fusarium solani</i> (root rot) and <i>Trichoderma atroviride</i> (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 <i>Bacillus</i> strains. Thus, the strains assayed in this study show potential as biocontrol agents against various <i>Fusarium</i> and <i>Trichoderma</i> species.</p></div

Biosurfactant properties of lipopeptide-producing <i>Bacillus</i> species.

<p>Biosurfactant properties of lipopeptide-producing <i>Bacillus</i> species.</p

Biosurfactant activity of lipopeptide-producing <i>Bacillus</i> species at different time intervals.

<p>Bars indicate the standard error from three replicates. All treatments are significantly different from each other according to the analysis of variance (p < 0.05). Experiments were repeated in triplicate with three replicates. <i>Bacillus</i> strains were grown in the optimum medium for lipopeptide production at 28°C. The surface tension of the water was 72 mN m^-1.</p

MS-ESI scan of lipopeptides produced by <i>B</i>.<i>subtilis</i> NH-100.

<p>MS-ESI scan of lipopeptides produced by <i>B</i>.<i>subtilis</i> NH-100.</p

Additional file 1: of Complete genome sequence of the heavy metal resistant bacterium Agromyces aureus AR33T and comparison with related Actinobacteria

Table S1. Primers used for gap closing. Figure S1. Bidirectional best hit analysis performed in RAST. Figure S2. Blast Dot Plot of Agromyces aureus AR33 versus Agromyces sp. Leaf222 calculated in RAST. Figure S3. Heat map showing similarities between whole genomes of A. aureus AR33 , other Agromyces spp. and related members of the same family and phylum. (PDF 277 kb