Organic Connection of Holobiont Components and the Essential Roles of Core Microbes in the Holobiont Formation of Feral Brassica napus

Abstract

Brassica napus (Rapeseed) is an econfomically important oil-producing crop. The microbial interactions in the plant holobiont are fundamental to the understanding of plant growth and health. To investigate the microbial dynamics in the holobiont of feral B. napus, a total of 215 holobiont samples, comprised of bulk soil, primary root, lateral root, dead leaf, caulosphere, basal leaf, apical leaf, carposphere, and anthosphere, were collected from five different grassland sites in South Korea. The soil properties differed in different sampling sites, but prokaryotic communities were segregated according to plant holobiont components. The structures of the site-specific SparCC networks were similar across the regions. Recurrent patterns were found in the plant holobionts in the recurrent network. Ralstonia sp., Massilia sp., and Rhizobium clusters were observed consistently and were identified as core taxa in the phyllosphere, dead leaf microbiome, and rhizosphere, respectively. Arthropod-related microbes, such as Wolbachia sp., Gilliamella sp., and Corynebacteriales amplicon sequence variants, were found in the anthosphere. PICRUSt2 analysis revealed that microbes also possessed specific functions related to holobiont components, such as functions related to degradation pathways in the dead leaf microbiome. Structural equation modeling analysis showed the organic connections among holobiont components and the essential roles of the core microbes in the holobiont formations in natural ecosystem. Microbes coexisting in a specific plant showed relatively stable community structures, even though the regions and soil characteristics were different. Microbes in each plant component were organically connected to form their own plant holobiont. In addition, plant-related microbes, especially core microbes in each holobiont, showed recurrent interaction patterns that are essential to an understanding of the survival and coexistence of plant microbes in natural ecosystems.

Effectiveness of a Priority Management Scheme of Living Modified Organism Re-Collection Areas in Natural Environments of South Korea

“…As shown in Figure 1, the MOE and NIE surveyed unintentionally released LMOs in natural environments from 2009 to 2013 and analyzed the LMO collection sites to develop a suitable management system. A total of 113 LMOs were detected at 65 sites, and 52 LMOs were re-collected at the same sites (25). This result indicates that LMO spillage may likely occur in areas where they have previously been detected, and that intensive surveys and management of LMO re-collection sites are necessary.…”

“…In line with the One Health concept, the root exudates of LMO plants, which contain engineered proteins, may have either positive or negative effects on the health of soil microorganisms in natural environments. Then, soil microbiomes may play a crucial role in the overall health of other ecosystem components, including plants and animals [22][23][24][25][26]. Therefore, this paper aims to highlight the significance of a new priority management system for One Health by mitigating the potential risks associated with LMO spillage in the natural ecosystem.…”

Tillandsia landbeckii phyllosphere and laimosphere as refugia for bacterial life in a hyperarid desert environment

“…Likewise, several of the dominant genera (> 10% relative abundance in a phyllosphere sample; Figure S3) are well-known phyllosphere colonizers. This applies to all dominant Gammaproteobacteria, i.e., Pseudomonas, Massilia, and Ralstonia, as well as Hymenobacter (class Bacteroidia), which have all been reported to occur prominently or as part of a phyllosphere core microbiota on other plants (e.g., [14,51,[60][61][62][63][64][65][66]). Similarly, dominant genera within the class Actinobacteria, i.e., Modestobacter and Kineococcus, are known as phyllosphere colonizers [51,61].…”

“…Similarly, the genera Wolbachia and "Candidatus Uzinura" occurred dominantly in the phyllosphere of some T. landbeckii individuals. These organisms are known as endosymbionts from plant(-sap) feeding arthropods and may use plants as intermediate hosts, being possibly transferred to plant tissue upon insect feeding [60,[76][77][78]. This is supported by a rather inconsistent occurrence of these taxa on plant individuals within and between the study sites, which is a logical consequence of selective (e.g., related to plant fitness) or stochastic insect attacks of plant individuals.…”

“…The most abundant ASV (ASV406, 32.9% mean relative abundance) in the phyllosphere was representing Ralstonia and had a log 2 fold change of 2.5 in comparison to the laimosphere. Ralstonia has been reported as dominant or consistent phyllosphere colonizer in some other studies [60,63,79]. The genus contains some serious soil-born plant pathogens (Ralstonia solanacearum, Ralstonia syzygii, Ralstonia pseudosolanacearum) causing bacterial wilt [80], but is not yet known as pathogen of Bromeliaceae.…”