The role of rhizosphere microbiota in the resistance of tomato plant against soil-borne Fusarium wilt disease (FWD) remains unclear. Here, we showed that the FWD incidence was ...significantly negatively correlated with the diversity of both rhizosphere bacterial and fungal communities. Using the microbiological culturomic approach, we selected 205 unique strains to construct different synthetic communities (SynComs), which were inoculated into germ-free tomato seedlings, and their roles in suppressing FWD were monitored using omics approach. Cross-kingdom (fungi and bacteria) SynComs were most effective in suppressing FWD than those of Fungal or Bacterial SynComs alone. This effect was underpinned by a combination of molecular mechanisms related to plant immunity and microbial interactions contributed by the bacterial and fungal communities. This study provides new insight into the dynamics of microbiota in pathogen suppression and host immunity interactions. Also, the formulation and manipulation of SynComs for functional complementation constitute a beneficial strategy in controlling soil-borne disease.
Abstract
Background
The plant microbiome is an integral part of the host and increasingly recognized as playing fundamental roles in plant growth and health. Increasing evidence indicates that plant ...rhizosphere recruits beneficial microbes to the plant to suppress soil-borne pathogens. However, the ecological processes that govern plant microbiome assembly and functions in the below- and aboveground compartments under pathogen invasion are not fully understood. Here, we studied the bacterial and fungal communities associated with 12 compartments (e.g., soils, roots, stems, and fruits) of chili pepper (
Capsicum annuum
L.) using amplicons (16S and ITS) and metagenomics approaches at the main pepper production sites in China and investigated how
Fusarium
wilt disease (FWD) affects the assembly, co-occurrence patterns, and ecological functions of plant-associated microbiomes.
Results
The amplicon data analyses revealed that FWD affected less on the microbiome of pepper reproductive organs (fruit) than vegetative organs (root and stem), with the strongest impact on the upper stem epidermis. Fungal intra-kingdom networks were less stable and their communities were more sensitive to FWD than the bacterial communities. The analysis of microbial interkingdom network further indicated that FWD destabilized the network and induced the ecological importance of fungal taxa. Although the diseased plants were more susceptible to colonization by other pathogenic fungi, their below- and aboveground compartments can also recruit potential beneficial bacteria. Some of the beneficial bacterial taxa enriched in the diseased plants were also identified as core taxa for plant microbiomes and hub taxa in networks. On the other hand, metagenomic analysis revealed significant enrichment of several functional genes involved in detoxification, biofilm formation, and plant-microbiome signaling pathways (i.e., chemotaxis) in the diseased plants.
Conclusions
Together, we demonstrate that a diseased plant could recruit beneficial bacteria and mitigate the changes in reproductive organ microbiome to facilitate host or its offspring survival. The host plants may attract the beneficial microbes through the modulation of plant-microbiome signaling pathways. These findings significantly advance our understanding on plant-microbiome interactions and could provide fundamental and important data for harnessing the plant microbiome in sustainable agriculture.
Mentoring skills are valuable assets for academic medicine and allied health faculty, who influence and help shape the careers of the next generation of healthcare providers. Mentors are role models ...who also act as guides for students’ personal and professional development over time. Mentors can be instrumental in conveying explicit academic knowledge required to master curriculum content. Importantly, they can enhance implicit knowledge about the “hidden curriculum” of professionalism, ethics, values, and the art of medicine not learned from texts. In many cases, mentors also provide emotional support and encouragement. It must be noted that to be an effective mentor, one must engage in ongoing learning in order to strengthen and further mentoring skills. Thus, learning communities can provide support, education, and personal development for the mentor. The relationship benefits mentors as well through greater productivity, career satisfaction, and personal gratification. Maximizing the satisfaction and productivity of such relationships entails self-awareness, focus, mutual respect, and explicit communication about the relationship. In this article, the authors describe the development of optimal mentoring relationships, emphasizing the importance of different approaches to mentorship, roles of the mentors and mentees, mentor and mentee benefits, interprofessional mentorships for teams, gender and mentorship, and culture and mentorship.
This study is one of the very few investigating the dioxin body burden of a group of child-bearing-aged women at an electronic waste (e-waste) recycling site (Taizhou, Zhejiang Province) (24 ± 2.83 ...years of age, 40% were primiparae) and a reference site (Lin'an city, Zhejiang Province, about 245 km away from Taizhou) (24 ± 2.35 years of age, 100% were primiparae) in China. Five sets of samples (each set consisted of human milk, placenta, and hair) were collected from each site. Body burdens of people from the e-waste processing site (human milk, 21.02 ± 13.81 pg WHO-TEQ1998/g fat (World Health Organization toxic equivalency 1998); placenta, 31.15 ± 15.67 pg WHO-TEQ1998/g fat; hair, 33.82 ± 17.74 pg WHO-TEQ1998/g dry wt) showed significantly higher levels of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs) than those from the reference site (human milk, 9.35 ± 7.39 pg WHO-TEQ1998/g fat; placenta, 11.91 ± 7.05 pg WHO-TEQ1998/g fat; hair, 5.59 ± 4.36 pg WHO-TEQ1998/g dry wt) and were comparatively higher than other studies. The difference between the two sites was due to e-waste recycling operations, for example, open burning, which led to high background levels. Moreover, mothers from the e-waste recycling site consumed more foods of animal origin. The estimated daily intake of PCDD/Fs within 6 months by breast-fed infants from the e-waste processing site was 2 times higher than that from the reference site. Both values exceeded the WHO tolerable daily intake for adults by at least 25 and 11 times, respectively. Our results implicated that e-waste recycling operations cause prominent PCDD/F levels in the environment and in humans. The elevated body burden may have health implications for the next generation.
Non-alcoholic fatty liver disease (NAFLD) is a severe liver disease that is increasing in prevalence with the worldwide epidemic of obesity and its related insulin-resistance state. A ‘two-hit’ ...mechanism has been proposed; however, the complete physiopathogenesis remains incompletely understood. Evidence for the role of the gut microbiota in energy storage and the subsequent development of obesity and some of its related diseases is now well established. More recently, a new role of gut microbiota has emerged in NAFLD. The gut microbiota is involved in gut permeability, low-grade inflammation and immune balance, it modulates dietary choline metabolism, regulates bile acid metabolism and produces endogenous ethanol. All of these factors are molecular mechanisms by which the microbiota can induce NAFLD or its progression toward overt non-alcoholic steatohepatitis.
To determine whether the supplementation of parenteral nutrition with ω-3 fatty acids confers treatment benefits to critically ill adult patients.
We performed computerized searches for relevant ...articles from 1996 to June 2011 on MEDLINE, EMBASE, and the Cochrane register of controlled trials and abstracts of scientific meetings from 2005 to 2011.
Randomized controlled trials of ω-3 fatty acid supplemented parenteral nutrition in critically ill adult patients admitted to the intensive therapy unit, given in addition to their routine care, compared with parenteral nutrition without ω-3 fatty acid supplementation.
Five fully published trials and three trials published in abstract form with 391 participants have been included. Overall trial quality was poor. Mortality data were pooled from eight studies with 391 participants. No differences were found with a risk ratio for death of 0.83 (95% confidence interval 0.57, 1.20; p = 0.32). Data for infectious complications were available from five studies with 337 participants. No differences were found, with a risk ratio for infection of 0.78 (95% confidence interval 0.43, 1.41; p = 0.41). Data for intensive therapy unit and hospital length of stay were available from six and three studies with 305 and 117 participants, respectively. With respect to intensive therapy unit length of stay, no differences were observed with a mean difference of 0.57 days in favor of the ω-3 fatty acid group (95% confidence interval -5.05, 3.90; p = 0.80). A significant reduction in hospital length of stay of 9.49 days (95% confidence interval -16.51, -2.47; p = 0.008) was observed for those receiving ω-3 fatty acid supplemented parenteral nutrition, but results were strongly influenced by one small study.
On the basis of this systematic review, it can be concluded that ω-3 fatty acid supplementation of parenteral nutrition does not improve mortality, infectious complications, and intensive therapy unit length of stay in comparison with standard parenteral nutrition. Although ω-3 fatty acids appear to reduce hospital length of stay, the poor methodology of the included studies and the absence of other outcome improvements mean they cannot be presently recommended.
In western North America, the current outbreak of the mountain pine beetle (MPB) and its microbial associates has destroyed wide areas of lodgepole pine forest, including more than 16 million ...hectares in British Columbia. Grosmannia clavigera (Gc), a critical component of the outbreak, is a symbiont of the MPB and a pathogen of pine trees. To better understand the interactions between Gc, MPB, and lodgepole pine hosts, we sequenced the ~30-Mb Gc genome and assembled it into 18 supercontigs. We predict 8,314 protein-coding genes, and support the gene models with proteome, expressed sequence tag, and RNA-seq data. We establish that Gc is heterothallic, and report evidence for repeat-induced point mutation. We report insights, from genome and transcriptome analyses, into how Gc tolerates conifer-defense chemicals, including oleoresin terpenoids, as they colonize a host tree. RNA-seq data indicate that terpenoids induce a substantial antimicrobial stress in Gc, and suggest that the fungus may detoxify these chemicals by using them as a carbon source. Terpenoid treatment strongly activated a ~100-kb region of the Gc genome that contains a set of genes that may be important for detoxification of these host-defense chemicals. This work is a major step toward understanding the biological interactions between the tripartite MPB/fungus/forest system.
Soil and plant‐associated protistan communities play a key role in shaping bacterial and fungal communities, primarily through their function as top‐down predators. However, our understanding of how ...pathogen invasion influences these protistan communities and their relationships with bacterial and fungal communities remains limited. Here, we studied the protistan communities along the soil–plant continuum of healthy chilli peppers and those affected by Fusarium wilt disease (FWD), and integrated bacterial and fungal community data from our previous research. Our research showed that FWD was associated with a significant enrichment of phagotrophic protists in roots, and also increased the proportion and connectivity of these protists (especially Cercozoa and Ciliophora) in both intra‐ and inter‐kingdom networks. Furthermore, the microbiome of diseased plants not only showed a higher relative abundance of functional genes related to bacterial anti‐predator responses than healthy plants, but also contained a greater abundance of metagenome‐assembled genomes with functional traits involved in this response. The increased microbial inter‐kingdom associations between bacteria and protists, coupled with the notable bacterial anti‐predator feedback in the microbiome of diseased plants, suggest that FWD may catalyse the associations between protists and their microbial prey. These findings highlight the potential role of predatory protists in influencing microbial assembly and functionality through top‐down forces under pathogenic stress.
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