Metabolic engineers endeavor to create a bio-based manufacturing industry using microbes to produce fuels, chemicals, and medicines. Plant natural products (PNPs) are historically challenging to ...produce and are ubiquitous in medicines, flavors, and fragrances. Engineering PNP pathways into new hosts requires finding or modifying a suitable host to accommodate the pathway, planning and implementing a biosynthetic route to the compound, and discovering or engineering enzymes for missing steps. In this review, we describe recent developments in metabolic engineering at the level of host, pathway, and enzyme, and discuss how the field is approaching ever more complex biosynthetic opportunities.
Beneficial interactions between plant roots and rhizosphere microorganisms are pivotal for plant fitness. Nevertheless, the molecular mechanisms controlling the feedback between root architecture and ...microbial community structure remain elusive in maize. Here, we demonstrate that transcriptomic gradients along the longitudinal root axis associate with specific shifts in rhizosphere microbial diversity. Moreover, we have established that root-derived flavones predominantly promote the enrichment of bacteria of the taxa Oxalobacteraceae in the rhizosphere, which in turn promote maize growth and nitrogen acquisition. Genetic experiments demonstrate that LRT1-mediated lateral root development coordinates the interactions of the root system with flavone-dependent Oxalobacteraceae under nitrogen deprivation. In summary, these experiments reveal the genetic basis of the reciprocal interactions between root architecture and the composition and diversity of specific microbial taxa in the rhizosphere resulting in improved plant performance. These findings may open new avenues towards the breeding of high-yielding and nutrient-efficient crops by exploiting their interaction with beneficial soil microorganisms.
Bacteria and fungi behind cheese, soy, and more share genomic traits wth domesticated plants and animals
Bacteria and fungi behind cheese, soy, and more share genomic traits wth domesticated plants ...and animals
Insect frass and exuviae to promote plant growth and health Barragán-Fonseca, Katherine Y.; Nurfikari, Azkia; van de Zande, Els M. ...
Trends in plant science,
July 2022, 2022-Jul, 2022-07-00, 20220701, Letnik:
27, Številka:
7
Journal Article
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Beneficial soil microorganisms can contribute to biocontrol of plant pests and diseases, induce systemic resistance (ISR) against attackers, and enhance crop yield. Using organic soil amendments has ...been suggested to stimulate the abundance and/or activity of beneficial indigenous microbes in the soil. Residual streams from insect farming (frass and exuviae) contain chitin and other compounds that may stimulate beneficial soil microbes that have ISR and biocontrol activity. Additionally, changes in plant phenotype that are induced by beneficial microorganisms may directly influence plant–pollinator interactions, thus affecting plant reproduction. We explore the potential of insect residual streams derived from the production of insects as food and feed to promote plant growth and health, as well as their potential benefits for sustainable agriculture.
Microbes with biocontrol or plant growth-promoting properties may reduce the use of synthetic pesticides and fertilisers and thereby support sustainable crop production.While the persistence and effectiveness of introduced single microbial agents in the field are often insufficient, organic soil amendments can serve as substrates to promote naturally occurring beneficial microbes.Insect-derived products such as exuviae and frass contain chitin and are rich in nitrogen as well as other nutrients that can improve soil quality and plant growth.Insect exuviae are colonised by potentially plant-protective or plant growth-promoting bacteria when added to soil.As the industrial production of insects for food and feed is increasing rapidly, large quantities of insect-derived products become available for soil amendment.
To determine the relationship between home disinfectant use and the prevalence of antibiotic resistance among environmental isolates of human pathogens.
Bacteria were cultured from 5 kitchen and 5 ...bathroom sites using quantitative methods. Antibiotic susceptibility was determined by standard methods. Home disinfectant use was assessed via a questionnaire.
The overall total mean log10 counts (total CFU) for the kitchen and bathroom were 4.31 and 4.88, respectively. Gram-positive bacteria were more common in the bathroom (4.05) than in the kitchen (3.60), while Gram-negative bacilli were more common in the kitchen (4.23) than in the bathroom (3.86). The sink and bath drains were the most contaminated sites with 6.16-log10 of total CFU and 6.6-log10 in the kitchen and bathroom, respectively.
Households reported cleaning frequency with a variety of commercial products. Most respondents used antibacterial products (eg, soaps, surface disinfectants) in the home. Antibiotic-resistant pathogens were infrequently isolated in the homes evaluated.
Compared to pathogens causing community-acquired clinical infections in the ICARE study, pathogens isolated from households are less likely to demonstrate antibiotic resistance. In addition, no relationship between antibacterial use or frequency of cleaning or disinfection and antibiotic resistance was revealed.
...Antibiotic-resistant pathogens were infrequently isolated in the homes evaluated...No relationship between antibacterial use or frequency of cleaning or disinfection and antibiotic resistance was revealed...Total mean log10 CFU for kitchen and bathroom were 4.31 and 4.88, respectively.
Tomato variety Hawaii 7996 is resistant to the soil-borne pathogen Ralstonia solanacearum, whereas the Moneymaker variety is susceptible to the pathogen. To evaluate whether plant-associated ...microorganisms have a role in disease resistance, we analyzed the rhizosphere microbiomes of both varieties in a mesocosm experiment. Microbiome structures differed between the two cultivars. Transplantation of rhizosphere microbiota from resistant plants suppressed disease symptoms in susceptible plants. Comparative analyses of rhizosphere metagenomes from resistant and susceptible plants enabled the identification and assembly of a flavobacterial genome that was far more abundant in the resistant plant rhizosphere microbiome than in that of the susceptible plant. We cultivated this flavobacterium, named TRM1, and found that it could suppress R. solanacearum-disease development in a susceptible plant in pot experiments. Our findings reveal a role for native microbiota in protecting plants from microbial pathogens, and our approach charts a path toward the development of probiotics to ameliorate plant diseases.
Chemolitho-autotrophic microorganisms like the nitrite-oxidizing Nitrobacter winogradskyi create an environment for heterotrophic microorganisms that profit from the production of organic compounds. ...It was hypothesized that the assembly of a community of heterotrophic microorganisms around N. winogradskyi depends on the ecosystem from which the heterotrophs are picked. To test this hypothesis, pure cultures of N. winogradskyi were grown in continuously nitrite-fed bioreactors in a mineral medium free of added organic carbon that had been inoculated with diluted sewage sludge or with a suspension from a grassland soil. Samples for chemical and 16S rRNA gene amplicon analyses were taken after each volume change in the bioreactor. At the end of the enrichment runs, samples for shotgun metagenomics were also collected. Already after two volume changes, the transformations in community structure became less dynamic. The enrichment of heterotrophs from both sewage and soil was highly stochastic and yielded different dominant genera in most of the enrichment runs that were independent of the origin of the inoculum. Hence, the hypothesis had to be refuted. Notwithstanding the large variation in taxonomic community structure among the enrichments, the functional compositions of the communities were statistically not different between soil- and sludge-based enrichments.
In the process of aerobic nitrification, nitrite-oxidizing bacteria together with ammonia-oxidizing microorganisms convert mineral nitrogen from its most reduced appearance, i.e., ammonium, into its most oxidized form, i.e., nitrate. Because the form of mineral nitrogen has large environmental implications, nitrite-oxidizing bacteria such as Nitrobacter winogradskyi play a central role in the global biogeochemical nitrogen cycle. In addition to this central role, the autotrophic nitrite-oxidizing bacteria also play a fundamental role in the global carbon cycle. They form the basis of heterotrophic food webs, in which the assimilated carbon is recycled. Little is known about the heterotrophic microorganisms that participate in these food webs, let alone their assembly in different ecosystems. This study showed that the assembly of microbial food webs by N. winogradskyi was a highly stochastic process and independent of the origin of the heterotrophic microorganisms, but the functional characteristics of the different food webs were similar.
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