EDITORIAL article Front. Plant Sci., 25 January 2024Sec. Plant Biotechnology Volume 15 - 2024 | https://doi.org/10.3389/fpls.2024.1367698

Biotechnology can provide a valuable tool to meet UN Sustainable Development Goals and U.S. initiatives to find climate solutions and improve agricultural sustainability. The literature contains hundreds of examples of crops that may serve this purpose, yet most remain un-launched due to high regulatory barriers. Recently the USDA revised its biotechnology regulations to make them more risk-proportionate, science-based, and streamlined. Here, we review some of the promising leads that may enable agriculture to contribute to UN sustainability goals. We further describe and discuss how the revised biotechnology regulation would hypothetically apply to these cases.

In keeping with the directive in Executive Order 13874 (Modernizing the Regulatory Framework for Agricultural Biotechnology Products) to adopt regulatory approaches that are proportionate to risk and avoid arbitrary distinctions across like products, the United States Department of Agriculture (USDA) revised its biotechnology regulations by promulgating the Sustainable, Ecological, Consistent, Uniform, Responsible, and Efficient (SECURE) rule. Specifically, the SECURE rule: 1) establishes exemptions for plants modified by genetic engineering where the modification could otherwise have been made through conventional breeding; 2) uses risk posed by the introduced trait to determine whether an organism is regulated, rather than relying on whether the organism was developed using a plant pest; and 3) provides a mechanism for a rapid initial review to efficiently distinguish plants developed using genetic engineering that do not pose plausible pathways to increased plant pest risk from those that do. As a result of the focused oversight on potentially riskier crops developed using genetic engineering, USDA is expected to improve the efficiency and effectiveness of its oversight program. The reduced regulatory burden is expected to promote innovation by expanding the number and diversity of developers to include smaller businesses and academics and to increase the number and variety of traits being developed through biotechnology.

In keeping with the directive in Executive Order 13874 (Modernizing the Regulatory Framework for Agricultural Biotechnology Products) to adopt regulatory approaches that are proportionate to risk and avoid arbitrary distinctions across like products, the US Department of Agriculture (USDA) revised its biotechnology regulations by promulgating the Sustainable, Ecological, Consistent, Uniform, Responsible, and Efficient (SECURE) rule. Specifically, the SECURE rule 1) establishes exemptions for plants modified by genetic engineering where the modification could otherwise have been made through conventional breeding, 2) uses risk posed by the introduced trait to determine whether an organism is regulated, rather than relying on whether the organism was developed using a plant pest, and 3) provides a mechanism for a rapid initial review to efficiently distinguish plants developed using genetic engineering that do not pose plausible pathways to increased plant pest risk from those that do. As a result of the focused oversight on potentially riskier crops developed using genetic engineering, USDA is expected to improve the efficiency and effectiveness of its oversight program. The reduced regulatory burden is expected to promote innovation by expanding the number and diversity of developers to include smaller businesses and academics and to increase the number and variety of traits being developed through biotechnology.

This report summarizes the research activities of WP-1754. The study focusses on the environmental factors influencing formation of lead free whiskers on electrodeposited tin coatings over copper (or copper containing) substrates. Much of the initial results are summarized in an interim report. From the initial results, two main areas were chosen to be the focus of additional research: the demonstration of effects of elastic stress state in the nucleation of whiskers and the confirmation of the effect of oxygen/nitrogen ratio in the formation of whiskers. Different levels of elastic stress were induced with the incorporation of a custom designed fixture that loaded the substrates in a four-point bending configuration and were maintained in an environmental chamber under conditions deemed favorable for whisker growth. The results show that induced elastic stress slightly increased the concentration of nucleation sites of whiskers. The effects of oxygen content were studied by aging substrates in gas vials of varying absolute pressure and different oxygen/nitrogen ratios. The concentration of whiskers were measured and appear to be sensitive to absolute pressure but are not sensitive to oxygen content (as previously observed).

A family of ternary carbides and nitrides, known as MAX phases, combine attractive properties of both ceramics and metals, and has been suggested for potential nuclear reactor applications. The unirradiated materials properties of importance for in-core structural materials and as fuel pellet coatings for several leading MAX phase materials have been summarized from literature. The materials show high mechanical damage tolerance in terms of creep, thermal/mechanical fatigue and fracture resistance, and very good chemical compatibility with select coolants such as molten lead and sodium. Neutron activation has been calculated for commercial purity materials exposed to both idealized fast and thermal reactor neutron spectra for 10, 30, and 60 years of exposure. The specific activities of Ti3SiC2, Ti3AlC2, and Ti2AlC were compared to those of SiC and Alloy 617, two leading candidate materials for next generation reactor components. The specific activities of MAX phases were similar to SiC and three orders of magnitude less than Alloy 617 after 10-60 years decay for all three activation times in both the fast and thermal spectra. As with SiC, the main radioisotopes after a decay period of 10 years for all three activation times in the MAX phases are tritium and C-14. Neutron irradiation results of Ti3SiC2, Ti3AlC2, and Ti2AlC experimentally confirmed the neutron transmutation analysis. Published by Elsevier B.V.

The Model 9975 shipping package specifies the materials of construction for its various components. With the loss of availability of material for two components (cane fiberboard overpack and Viton® GLT O-rings), alternate materials of construction were identified and approved for use for transport (softwood fiberboard and Viton® GLT-S O-rings). The shipping packages are part of a long-term storage configuration at the Savannah River Site (SRS). Therefore, additional testing is in progress to verify satisfactory long-term performance of the alternate materials under storage conditions. The test results to date can be compared to results on the original materials of construction to draw preliminary conclusions on the performance of the replacement materials.

Carbon fiber-reinforced bisphenol-A epoxy matrix composite was evaluated for gamma radiation resistance. The composite was exposed to total gamma doses of 0.5, 1.0, and 2.0MGy. Irradiated and baseline samples were tested for tensile strength, hardness and evaluated using Fourier transform infra-red spectroscopy and differential scanning calorimetry for structural changes. Scanning electron microscopy was used to evaluate microstructural behavior. Mechanical testing of the composite bars revealed no apparent change in modulus, strain to failure, or fracture strength after exposures. However, testing of only the epoxy matrix revealed changes in hardness, thermal properties, and spectroscopy results with increasing gamma irradiation. The results quantify the changes in the epoxy within the composite as a result of exposure to gamma radiation at doses relevant to service.

Using a synchrotron X-ray radiation source and a diamond anvil cell we measured the dependences of the lattice parameters on quasi-hydrostatic pressure of the order of 50 GPa of the following MAX phases:Ti2InC, (Ti-0.5, Zr-0.5)(2)InC, Zr2InC and Ti2SnC, Nb2InC and Hf2InC. Like other MAX phases, the phases studied herein were all stable up to approximate to 50 GPa. In both series, the substitution of Ti (r = 1.32 angstrom) by the larger sized metals, Zr or Nb (with r varying between 1.34 and 1.55 angstrom) resulted in larger unit cell parameters and volumes. At 152 +/- 3 and 148 +/- 3 GPa, the respective bulk moduli, K-o, of Ti2SnC and Ti2InC are quite comparable. Replacing Ti by Hf or Nb in Ti2SnC leads to increases in K-o by 11% and 18%, respectively. Conversely, replacing half the Ti by Zr in Ti2InC leads to a 13% drop in K-o; replacing all of the Ti drops it by 16.5%. Most of these trends are reproduced in our ab initio calculations of K-o For all compositions, the compressibilities along the c-direction were greater than those along the a-direction. For the M2SnC series, the compressibilities along the c-axes were quite similar; the compressibilities along the a-axis of Ti2SnC were greater than in the Nb- or Hf-containing ternaries. The c-axis compressibilities of the in-containing compounds were almost indistinguishable. The compressibilities along the a-axes of (T-i0.5, Zr-0.5)(2)InC and Zr2InC were also quite comparable; those of Ti2InC was less compressible. (C) 2009 Published by Elsevier Ltd

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The chloroplast signal recognition particle (cpSRP) and its receptor (cpFtsY) target proteins both cotranslationally and posttranslationally to the thylakoids. This dual function enables cpSRP to utilize its posttranslational activities for targeting a family of nucleus-encoded light-harvesting chlorophyll binding proteins (LHCPs), the most abundant membrane proteins in plants. Previous in vitro experiments indicated an absolute requirement for all cpSRP pathway soluble components. In agreement, a cpFtsY mutant in Arabidopsis thaliana exhibits a severe chlorotic phenotype resulting from a massive loss of LHCPs. Surprisingly, a double mutant, cpftsy cpsrp54, recovers to a great extent from the chlorotic cpftsy phenotype. This establishes that in plants, a new alternative pathway exists that can bypass cpSRP posttranslational targeting activities. Using a mutant form of cpSRP43 that is unable to assemble with cpSRP54, we complemented the cpSRP43-deficient mutant and found that this subunit is required for the alternative pathway. Along with the ability of cpSRP43 alone to bind the ALBINO3 translocase required for LHCP integration, our results indicate that cpSRP43 has developed features to function independently of cpSRP54/cpFtsY in targeting LHCPs to the thylakoid membranes.

In this paper we report on the synthesis of a composition, Ti3Al(C0.5,N0.5)2, belonging to the Mn+1AXn family of ternary layered carbides and nitrides. X-ray and selected area diffraction confirm that this compound is isostructural with Ti3SiC2; its a and c-lattice parameters are 3.0404(5) and 18.414(6) Å, respectively. Chemical analysis performed by electron dispersive and electron energy loss spectroscopy confirmed the Ti3AlCN chemistry. Using a synchrotron radiation source and a diamond anvil cell, we also measured the pressure dependencies of the lattice parameters. Up to a pressure of ≈50 GPa, no phase transformations were observed. The bulk modulus is 219±4 GPa, with a pressure derivative, Ko′, of 3.7±0.3. We also fabricated the ternary Ti3AlC2, with some Sn [nominal composition Ti3(AlSn0.2)C2]. Its a and c-lattice parameters are 3.0804(7) and 18.5426(7) Å, respectively. Its bulk modulus is 226±3 GPa, with a pressure derivative, Ko′, of ≈4. In both cases, the compressibility was greater along the c than along the a axes. We also show that in the case of Tin+1AlCn MAX-phases, replacing C by N results in a decrease in both lattice parameters and bulk moduli. The apparent contradiction inherent in this observation can be reconciled by assuming that the addition of N results in the formation of vacancies on the Al and/or X-sites.