Changes of the microbial community in kiwifruit during storage after postharvest application of Wickerhamomyces anomalus.

High-throughput sequencing techniques can provide important information for understanding the interaction between exogenous microbial agents and fruit microbial communities, and explain how it controls postharvest fungal diseases. In this study, we found that Wickerhamomyces anomalus could control the postharvest disease of kiwifruit. Meanwhile, high-throughput sequencing technology results showed that the composition and structure changes of the fungal community in microbial flora were significantly greater than those of bacteria after W. anomalus treated. W. anomalus could colonize inside the fruit and regulate the community composition of bacteria to reduce the abundance of pathogens and eventually maintain the healthy state of the fruit. The dominant genus in the microbiota of kiwifruit after application of W. anomalus showed an increased ability to interact. Some fungi or bacteria are positively associated with yeast in the epiphytic and endophytic sample communities, guiding the synthesis of compound biocontrol strains for kiwifruit postharvest diseases.

Analysis of Bacterial Communities on North Sea Macroalgae and Characterization of the Isolated Planctomycetes Adhaeretor mobilis gen. nov., sp. nov., Roseimaritima multifibrata sp. nov., Rosistilla ulvae sp. nov. and Rubripirellula lacrimiformis sp. nov.

Planctomycetes are bacteria that were long thought to be unculturable, of low abundance, and therefore neglectable in the environment. This view changed in recent years, after it was shown that members of the phylum Planctomycetes can be abundant in many aquatic environments, e.g., in the epiphytic communities on macroalgae surfaces. Here, we analyzed three different macroalgae from the North Sea and show that Planctomycetes is the most abundant bacterial phylum on the alga Fucus sp., while it represents a minor fraction of the surface-associated bacterial community of Ulva sp. and Laminaria sp. Especially dominant within the phylum Planctomycetes were Blastopirellula sp., followed by Rhodopirellula sp., Rubripirellula sp., as well as other Pirellulaceae and Lacipirellulaceae, but also members of the OM190 lineage. Motivated by the observed abundance, we isolated four novel planctomycetal strains to expand the collection of species available as axenic cultures since access to different strains is a prerequisite to investigate the success of planctomycetes in marine environments. The isolated strains constitute four novel species belonging to one novel and three previously described genera in the order Pirellulales, class Planctomycetia, phylum Planctomycetes.

Plant Microbiome and Its Link to Plant Health: Host Species, Organs and Pseudomonas syringae pv. actinidiae Infection Shaping Bacterial Phyllosphere Communities of Kiwifruit Plants.

Pseudomonas syringae pv. actinidiae (Psa) is the causal agent of the bacterial canker, the most devastating disease of kiwifruit vines. Before entering the host tissues, this pathogen has an epiphytic growth phase on kiwifruit flowers and leaves, thus the ecological interactions within epiphytic bacterial community may greatly influence the onset of the infection process. The bacterial community associated to the two most important cultivated kiwifruit species, Actinidia chinensis and Actinidia deliciosa, was described both on flowers and leaves using Illumina massive parallel sequencing of the V3 and V4 variable regions of the 16S rRNA gene. In addition, the effect of plant infection by Psa on the epiphytic bacterial community structure and biodiversity was investigated. Psa infection affected the phyllosphere microbiome structures in both species, however, its impact was more pronounced on A. deliciosa leaves, where a drastic drop in microbial biodiversity was observed. Furthermore, we also showed that Psa was always present in syndemic association with Pseudomonas syringae pv. syringae and Pseudomonas viridiflava, two other kiwifruit pathogens, suggesting the establishment of a pathogenic consortium leading to a higher pathogenesis capacity. Finally, the analyses of the dynamics of bacterial populations provided useful information for the screening and selection of potential biocontrol agents against Psa.

Feeding electivity of two epiphytic chironomids in a subtropical lake.

Feeding electivity of two epiphytic orthoclad chironomid species, Psectrocladius sp. and Thienemanniella cf. fusca, was investigated using gut content analysis of larvae collected from Typha stems in Lake Padgett, Florida. Electivity values, computed using Strauss's Food Selection Index, were strongly positive for Cosmarium and negative for Oedogonium and Bulbochaete. Diatoms either were avoided or grazed in proportion to their abundance in the environment. Patterns of electivity were similar for both chrionomid species during all seasons studied. Pairwise food preference experiments were conducted in the laboratory using the algal species, Cosmarium impressulum, Navicula pelliculosa, Selenastrum capricornuatum, Oedogonium cardiacum, and Synedra sp. Preferences were hierarchical and consistent for both larval genera. Preference ranking for the algae offered were Cosmarium≥Synedra>Navicula>Oedogonium>Selenastrum. Larvae seemed to be feeding electively based upon algal genus, size, position in the epiphytic community, and possibly extracellular chemistry.