Bacterial Dispersers along Preferential Flow Paths of a Clay Till Depth Profile

Synergistic effects of organic carbon and silica in preserving structural stability of drying soils

Predicted climate warming and prolonged droughts pose a threat to the soil structure as organic carbon losses weaken the stability of soil aggregates. Well-structured soils are important for storage and movement of water, solutes, and air, the development of plant roots, as habitat for soil organisms, and the microbial activity. Structural stability is measured in terms of hydro-mechanical properties. This study compares effects of amorphous silica with those of organic carbon on stability parameters during drying of aggregates from relatively finer- and coarser-textured soils. Silica amendment enhanced the positive effect of organic carbon on structural stability in terms of the tensile strength. Synergistic effects between silica and organic carbon in soil colloids appear to dynamically alter aggregate density and friability (i.e., ability to crumble) during drying. Silica together with organic carbon could help soil management to reduce negative effects of predicted prolonged droughts on soil structure and stability.

Analysis of microbial community diversity of muscadine grape skins

Microorganisms in grape skins play vital roles in grapevine health, productivity, wine quality and organoleptic properties. To investigate microbial diversity of muscadine grape skins, 16S and ITS sequences of 30 samples from six muscadine (Muscadinia rotundifolia Michx.) cultivars grown in Guangxi, China, were sequenced using Illumina Novaseq platform. A total of 7,317 bacterial operational taxonomic units (OTUs) and 1,611 fungal OTUs were obtained, and clustered into 38 bacterial and 7 known fungal phyla. The dominant bacterial phyla were Proteobacteria, Firmicutes, Bacteroidetes, Planctomycetes, Actinobacteria, Verrucomicrobia, Acidobacteria, and Patescibacteria, and the dominant genera were Lelliottia, Prevotella_9, Escherichia-Shigella, Lactobacillus, Pseudomonas, Akkermansia, Faecalibacterium, Rahnella, and Acinetobacter. For fungi, the dominant phyla were Ascomycota, Basidiomycota, and Mortierellomycota, and the dominant genera were Acaromyces, Uwebraunia, Penicillium, Zygosporium, Ilyonectria, Aspergillus, Neodevriesia, Strelitziana, Mortierella, and Fusarium. Alpha diversity analysis and Kruskal-Wallis H test demonstrated that microbial diversity and composition were affected by the cultivar. The Pearson correlation analysis of species revealed complex interactions among microbes. PICRUSt2 predicted that the metabolism of carbohydrates, cofactors, vitamins, amino acids, terpenoids, polyketides, lipids and biosynthesis of other secondary metabolites were abundant. These results contribute to understanding the uniqueness of muscadine grapes and the links among microorganisms in grape skins.

Can dispersal be leveraged to improve microbial inoculant success?

Microorganisms have long been isolated from soils to develop microbial inoculants, with the goal of spiking them into new soils to augment target functions. However, establishment can be sporadic, and we assume that inoculants simply arrive at their destination. Here, we posit a need for integrating dispersal into inoculant development and deployment. We argue that consideration for an inoculant's dispersal ability, whether via active (e.g., chemotaxis) or passive (e.g., attachment to other organisms) means, and including methods of deployment that allow multiple establishment attempts could help increase the predictability of inoculant success. Dispersal can influence many key aspects of in-field survival, including the ability to escape stressors, seek favorable colonization sites, facilitate multiple establishment attempts, and engage in multikingdom interactions.