Biological nitrogen fixation in maize: optimizing nitrogenase expression in a root-associated diazotroph

Bloch, Sarah E.; Clark, Rosemary; Gottlieb, Shayin S; Wood, L. K.; Shah, Neal; Mak, San-Ming; Lorigan, James G.; Johnson, Jenny; Davis-Richardson, Austin G.; Williams, Lorena; McKellar, Megan; Soriano, Dominic; Petersen, Max; Horton, Alana; Smith, Olivia; Wu, Leslie; Tung, Emily; Broglie, Richard; Tamsir, Alvin; Temme, Karsten

doi:10.1093/jxb/eraa176

Cited by 58 publications

(46 citation statements)

References 53 publications

(64 reference statements)

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“…These cases benefit from plasmids stabilized with additional systems (Easter et al , ; Prell et al , ; Fedorec et al , ). When cells have to be maintained over long periods in a competitive environment, for example, in the microbiota in the human gut or in soil in agriculture, then it is important to reduce the resource utilization(Klumpp et al , ; Liao et al , ; Riglar et al , ; Ceroni et al , ; Bloch et al , ). Similarly, in bio‐production applications that are sensitive to titers and yields from feedstock, the circuit needs to have essentially no growth impact and minimal draw on carbon or energy resources.…”

Section: Discussionmentioning

confidence: 99%

P recision design of stable genetic circuits carried in highly‐insulated E. coli genomic landing pads

Park

Borujeni

Gorochowski

et al. 2020

Molecular Systems Biology

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Genetic circuits have many applications, from guiding living therapeutics to ordering process in a bioreactor, but to be useful they have to be genetically stable and not hinder the host. Encoding circuits in the genome reduces burden, but this decreases performance and can interfere with native transcription. We have designed genomic landing pads in Escherichia coli at high‐expression sites, flanked by ultrastrong double terminators. DNA payloads >8 kb are targeted to the landing pads using phage integrases. One landing pad is dedicated to carrying a sensor array, and two are used to carry genetic circuits. NOT/NOR gates based on repressors are optimized for the genome and characterized in the landing pads. These data are used, in conjunction with design automation software (Cello 2.0), to design circuits that perform quantitatively as predicted. These circuits require fourfold less RNA polymerase than when carried on a plasmid and are stable for weeks in a recA+ strain without selection. This approach enables the design of synthetic regulatory networks to guide cells in environments or for applications where plasmid use is infeasible.

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Section: Discussionmentioning

confidence: 99%

P recision design of stable genetic circuits carried in highly‐insulated E. coli genomic landing pads

Park

Borujeni

Gorochowski

et al. 2020

Molecular Systems Biology

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“…The further scope of nitrogen fixation through aerial roots in cereals has been discussed in detail [ 181 ]. The other novel strains with optimized nitrogenase expression are continuously sought and discovered [ 182 ]. Genetic engineering of non-nodulating microbes to expand nitrogen fixation in cereal crops presents another opportunity to meet the nitrogen demand through a symbiotic process.…”

Section: Nitrogen Fixation In Cerealsmentioning

confidence: 99%

Molecular Biology in the Improvement of Biological Nitrogen Fixation by Rhizobia and Extending the Scope to Cereals

2021

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The contribution of biological nitrogen fixation to the total N requirement of food and feed crops diminished in importance with the advent of synthetic N fertilizers, which fueled the “green revolution”. Despite being environmentally unfriendly, the synthetic versions gained prominence primarily due to their low cost, and the fact that most important staple crops never evolved symbiotic associations with bacteria. In the recent past, advances in our knowledge of symbiosis and nitrogen fixation and the development and application of recombinant DNA technology have created opportunities that could help increase the share of symbiotically-driven nitrogen in global consumption. With the availability of molecular biology tools, rapid improvements in symbiotic characteristics of rhizobial strains became possible. Further, the technology allowed probing the possibility of establishing a symbiotic dialogue between rhizobia and cereals. Because the evolutionary process did not forge a symbiotic relationship with the latter, the potential of molecular manipulations has been tested to incorporate a functional mechanism of nitrogen reduction independent of microbes. In this review, we discuss various strategies applied to improve rhizobial strains for higher nitrogen fixation efficiency, more competitiveness and enhanced fitness under unfavorable environments. The challenges and progress made towards nitrogen self-sufficiency of cereals are also reviewed. An approach to integrate the genetically modified elite rhizobia strains in crop production systems is highlighted.

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“…Many PGP microbes have been isolated, and some are widely accepted as biofertilizers, biostimulants, and biocontrol agents (www.cropscience.bayer.com/innovations/agriculturebiologicals/a/hidden-helpers-below-ground). However, applying PGP microbes to fields for commercial adoption has had limited success [8][9][10][11][12]. This is likely because the new microbes are excluded by the more-resilient existing microbial communities [13], whose composition has been shaped over time through complex multilateral interactions with the environment [14][15][16][17][18][19][20].…”

mentioning

confidence: 99%

Microbiome Engineering: Synthetic Biology of Plant-Associated Microbiomes in Sustainable Agriculture

Wang

Yoshikuni

2021

Trends in Biotechnology

236

130

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To support an ever-increasing population, modern agriculture faces numerous challenges that pose major threats to global food and energy security. Plantassociated microbes, with their many plant growth-promoting (PGP) traits, have enormous potential in helping to solve these challenges. However, the results of their use in agriculture have been variable, probably because of poor colonization. Phytomicrobiome engineering is an emerging field of synthetic biology that may offer ways to alleviate this limitation. This review highlights recent advances in both bottom-up and top-down approaches to engineering non-model bacteria and microbiomes to promote beneficial plant-microbe interactions, as well as advances in strategies to evaluate these interactions. Biosafety, biosecurity, and biocontainment strategies to address the environmental concerns associated with field use of synthetic microbes are also discussed. Phytomicrobiome Engineering for Sustainable AgricultureThe United Nations estimates world population will be 9.8 billion people by 2050 (https:// population.un.org/wpp/). Agricultural productivity must increase by an estimated 70% to meet increasing demand for food, feed, fiber, and bioenergy (Global Agricultural Productivity Initiative: https://globalagriculturalproductivity.org/). Because arable acreage is unlikely to grow [1], meeting this demand requires achieving higher yields, currently attempted using artificial fertilizers and pesticides whose manufacture and use are not sustainable. Synthetic nitrogen (N) fertilizer production is energy-intensive [2]. Phosphorous (P) and potassium (K) fertilizers are mainly produced from finite mined resources likely to be depleted within 100 years. Pesticides with carcinogenic, developmental, and environmental risks are restricted [3,4]. More sustainable strategies to achieve ever-higher crop yield are urgently needed.Plant-associated microbes harbor enormous potential to provide economical and sustainable solutions to current agricultural challenges. Although plants provide diverse ecological niches for microbes [5,6], microbes provide plant growth-promoting (PGP) traits (see Glossary) for plants [7]. Many PGP microbes have been isolated, and some are widely accepted as biofertilizers, biostimulants, and biocontrol agents (www.cropscience.bayer.com/innovations/agriculturebiologicals/a/hidden-helpers-below-ground). However, applying PGP microbes to fields for commercial adoption has had limited success [8][9][10][11][12]. This is likely because the new microbes are excluded by the more-resilient existing microbial communities [13], whose composition has been shaped over time through complex multilateral interactions with the environment [14][15][16][17][18][19][20]. Finding new microorganisms that can sustainably support plant development, nutrition, fitness, disease control, and productivity in dynamic and stressful environments therefore depends on developing strategies to manage phytomicrobiomes [5,15,[21][22][23][24]. HighlightsMutualistic microbes associated w...

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Biological nitrogen fixation in maize: optimizing nitrogenase expression in a root-associated diazotroph

Cited by 58 publications

References 53 publications

P recision design of stable genetic circuits carried in highly‐insulated E. coli genomic landing pads

P recision design of stable genetic circuits carried in highly‐insulated E. coli genomic landing pads

Molecular Biology in the Improvement of Biological Nitrogen Fixation by Rhizobia and Extending the Scope to Cereals

Microbiome Engineering: Synthetic Biology of Plant-Associated Microbiomes in Sustainable Agriculture

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