Cytokinins regulate spatially-specific ethylene production to control root growth in Arabidopsis.

The two principal growth regulators cytokinins and ethylene are known to interact in the regulation of plant growth. However, information about underlying molecular mechanism and positional specificity of the cytokinin/ethylene crosstalk in root growth control is scarce. We have identified spatial specificity of cytokinin-regulated root elongation and root apical meristem (RAM) size, both of which we demonstrate to be dependent on ethylene biosynthesis. Upregulation of the cytokinin biosynthetic gene ISOPENTENYLTRANSFERASE (IPT) in proximal and peripheral tissues leads to both root and RAM shortening. In contrast, IPT activation in distal and inner tissues reduces RAM size while leaving the root length comparable to mock-treated controls. We show that cytokinins regulate two steps specific to ethylene biosynthesis, the production of ethylene precursor 1-aminocyclopropane-1-carboxylate (ACC) by ACC SYNTHASEs (ACSs), and its conversion to ethylene by ACC OXIDASEs (ACOs). We describe cytokinin- and ethylene-specific regulation controlling the activity of ACSs and ACOs that are spatially discrete along both proximo/distal and radial root axes. Using direct ethylene measurements, we identify ACO2, ACO3 and ACO4 as being responsible for ethylene biosynthesis and the ethylene-regulated root and RAM shortening in cytokinin-treated Arabidopsis. Direct interaction between ARABIDOPSIS RESPONSE REGULATOR 2 (ARR2), a member of the multistep phosphorelay cascade and the C-terminal portion of ETHYLENE INSENSITIVE 2 (EIN2-C), a key regulator of canonical ethylene signaling is involved in the cytokinin-induced, ethylene-mediated control of ACO4. We propose tight cooperation between cytokinin and ethylene signaling in the spatial-specific regulation of ethylene biosynthesis as a key aspect of hormonal control over root growth.

Scientific opinion on the ANSES analysis of Annex I of the EC proposal COM (2023) 411 (EFSA-Q-2024-00178).

EFSA was asked by the European Parliament to provide a scientific opinion on the analysis by the French Agency for Food, Environmental and Occupational Health & Safety (ANSES) of Annex I of the European Commission proposal for a regulation 'on plants obtained by certain new genomic techniques (NGTs) and their food and feed, and amending regulation (EU) 2017/625'. The Panel on genetically modified organisms (GMO) assessed the opinion published by ANSES, which focuses on (i) the need to clarify the definitions and scope, (ii) the scientific basis for the equivalence criteria and (iii) the need to take potential risks from category 1 NGT plants into account. The EFSA GMO Panel considered the ANSES analysis and comments on various terms used in the criteria in Annex I of the European Commission proposal and discussed definitions based on previous EFSA GMO Panel opinions. The EFSA GMO Panel concluded that the available scientific literature shows that plants containing the types and numbers of genetic modifications used as criteria to identify category 1 NGT plants in the European Commission proposal do exist as the result of spontaneous mutations or random mutagenesis. Therefore, it is scientifically justified to consider category 1 NGT plants as equivalent to conventionally bred plants with respect to the similarity of genetic modifications and the similarity of potential risks. The EFSA GMO Panel did not identify any additional hazards and risks associated with the use of NGTs compared to conventional breeding techniques in its previous Opinions.

New developments in biotechnology applied to microorganisms.

EFSA was requested by the European Commission (in accordance with Article 29 of Regulation (EC) No 178/2002) to provide a scientific opinion on the application of new developments in biotechnology (new genomic techniques, NGTs) to viable microorganisms and products of category 4 to be released into the environment or placed on the market as or in food and feed, and to non-viable products of category 3 to be placed on the market as or in food and feed. A horizon scanning exercise identified a variety of products containing microorganisms obtained with NGTs (NGT-Ms), falling within the remit of EFSA, that are expected to be placed on the (EU) market in the next 10 years. No novel potential hazards/risks from NGT-Ms were identified as compared to those obtained by established genomic techniques (EGTs), or by conventional mutagenesis. Due to the higher efficiency, specificity and predictability of NGTs, the hazards related to the changes in the genome are likely to be less frequent in NGT-Ms than those modified by EGTs and conventional mutagenesis. It is concluded that EFSA guidances are 'partially applicable', therefore on a case-by-case basis for specific NGT-Ms, fewer requirements may be needed. Some of the EFSA guidances are 'not sufficient' and updates are recommended. Because possible hazards relate to genotypic and phenotypic changes introduced and not to the method used for the modification, it is recommended that any new guidance should take a consistent risk assessment approach for strains/products derived from or produced with microorganisms obtained with conventional mutagenesis, EGTs or NGTs.

Assessment of genetically modified maize MON 89034 × 1507 × NK603 for renewal authorisation under Regulation (EC) No 1829/2003 (application GMFF-2022-3670).

Following the submission of dossier GMFF-2022-3670 under Regulation (EC) No 1829/2003 from Corteva Agriscience Belgium BV and Bayer Agriculture BV, the Panel on genetically modified organisms of the European Food Safety Authority was asked to deliver a scientific risk assessment on the data submitted in the context of the renewal of authorisation application for the herbicide-tolerant and insect-resistant genetically modified maize MON 89034 × 1507 × NK603, for food and feed uses, excluding cultivation within the European Union. The data received in the context of this renewal application contained post-market environmental monitoring reports, a systematic search and evaluation of literature, updated bioinformatic analyses and a search for additional documents or studies performed by or on behalf of the applicant. The GMO Panel assessed these data for possible new hazards, modified exposure or new scientific uncertainties identified during the authorisation period and not previously assessed in the context of the original application. Under the assumption that the DNA sequences of the events in maize MON 89034 × 1507 × NK603 considered for renewal are identical to the sequences of the originally assessed events, the GMO Panel concludes that there is no evidence in renewal dossier GMFF-2022-3670 for new hazards, modified exposure or scientific uncertainties that would change the conclusions of the original risk assessment on maize MON 89034 × 1507 × NK603.

Assessment of genetically modified maize MON 94804 (application GMFF-2022-10651).

Genetically modified (GM) maize MON 94804 was developed to achieve a reduction in plant height by introducing the GA20ox_SUP suppression cassette. The molecular characterisation and bioinformatic analyses do not identify issues requiring food/feed safety assessment. None of the agronomic/phenotypic and compositional differences identified between maize MON 94804 and its conventional counterpart needs further assessment, except for ear height, plant height and levels of carbohydrates in forage, which do not raise safety or nutritional concerns. The Panel on Genetically Modified Organisms (GMO Panel) does not identify safety concerns regarding the toxicity and allergenicity of the GA20ox_SUP precursor-miRNA and derived mature miRNA as expressed in maize MON 94804 and finds no evidence that the genetic modification would change the overall allergenicity of maize MON 94804. In the context of this application, the consumption of food and feed from maize MON 94804 does not represent a nutritional concern in humans and animals. The GMO Panel concludes that maize MON 94804 is as safe as the conventional counterpart and non-GM maize varieties tested, and no post-market monitoring of food/feed is considered necessary. In the case of accidental release of viable maize MON 94804 grains into the environment, this would not raise environmental safety concerns. The post-market environmental monitoring plan and reporting intervals are in line with the intended uses of maize MON 94804. The GMO Panel concludes that maize MON 94804 is as safe as its conventional counterpart and the tested non-GM maize varieties with respect to potential effects on human and animal health and the environment.

Assessment of genetically modified maize MON 89034 × 1507 × MON 88017 × 59122 and 8 out of 10 of its subcombinations for renewal authorisation under Regulation (EC) No 1829/2003 (dossier GMFF-2022-9170).

Following the joint submission of dossier GMFF-2022-9170 under Regulation (EC) No 1829/2003 from Bayer Agriculture B.V. and Corteva Agriscience Belgium B.V., the Panel on genetically modified organisms of the European Food Safety Authority was asked to deliver a scientific risk assessment on the data submitted in the context of the renewal of authorisation application for the herbicide tolerant and insect resistant genetically modified maize MON 89034 × 1507 × MON 88017 × 59122 and 8 out of 10 of its subcombinations, for food and feed uses, excluding cultivation within the European Union. The data received in the context of this renewal application contained post-market environmental monitoring reports, an evaluation of the literature retrieved by a scoping review, a search for additional studies performed by or on behalf of the applicant and updated bioinformatics analyses. The GMO Panel assessed these data for possible new hazards, modified exposure or new scientific uncertainties identified during the authorisation period and not previously assessed in the context of the original application. Under the assumption that the DNA sequences of the events in maize MON 89034 × 1507 × MON 88017 × 59122 and 8 out of 10 of its subcombinations considered for renewal are identical to the sequences of the originally assessed events, the GMO Panel concludes that there is no evidence in renewal dossier GMFF-2022-9170 for new hazards, modified exposure or scientific uncertainties that would change the conclusions of the original risk assessment on maize MON 89034 × 1507 × MON 88017 × 59122 and 8 out of 10 of its subcombinations.

High-Throughput Spike Detection in Greenhouse Cultivated Grain Crops with Attention Mechanisms-Based Deep Learning Models.

Detection of spikes is the first important step toward image-based quantitative assessment of crop yield. However, spikes of grain plants occupy only a tiny fraction of the image area and often emerge in the middle of the mass of plant leaves that exhibit similar colors to spike regions. Consequently, accurate detection of grain spikes renders, in general, a non-trivial task even for advanced, state-of-the-art deep neural networks (DNNs). To improve pattern detection in spikes, we propose architectural changes to Faster-RCNN (FRCNN) by reducing feature extraction layers and introducing a global attention module. The performance of our extended FRCNN-A vs. conventional FRCNN was compared on images of different European wheat cultivars, including "difficult" bushy phenotypes from 2 different phenotyping facilities and optical setups. Our experimental results show that introduced architectural adaptations in FRCNN-A helped to improve spike detection accuracy in inner regions. The mean average precision (mAP) of FRCNN and FRCNN-A on inner spikes is 76.0% and 81.0%, respectively, while on the state-of-the-art detection DNNs, Swin Transformer mAP is 83.0%. As a lightweight network, FRCNN-A is faster than FRCNN and Swin Transformer on both baseline and augmented training datasets. On the FastGAN augmented dataset, FRCNN achieved a mAP of 84.24%, FRCNN-A attained a mAP of 85.0%, and the Swin Transformer achieved a mAP of 89.45%. The increase in mAP of DNNs on the augmented datasets is proportional to the amount of the IPK original and augmented images. Overall, this study indicates a superior performance of attention mechanisms-based deep learning models in detecting small and subtle features of grain spikes.

Assessment of genetically modified maize DP202216 for food and feed uses, under Regulation (EC) No 1829/2003 (application EFSA-GMO-NL-2019-159).

Genetically modified maize DP202216 was developed to confer tolerance to glufosinate-ammonium-containing herbicides and to provide an opportunity for yield enhancement under field conditions. These properties were achieved by introducing the mo-pat and zmm28 expression cassettes. The molecular characterisation data and bioinformatic analyses do not identify issues requiring food/feed safety assessment. None of the identified differences in the agronomic/phenotypic and compositional characteristics tested between maize DP202216 and its comparator needs further assessment, except for the levels of stearic acid (C18:0), which do not raise nutritional and safety concerns. The GMO Panel does not identify safety concerns regarding the toxicity and allergenicity of the PAT and ZMM28 proteins as expressed in maize DP202216, and finds no evidence that the genetic modification would change the overall allergenicity of maize DP202216. In the context of this application, the consumption of food and feed from maize DP202216 does not represent a nutritional concern in humans and animals. The GMO Panel concludes that maize DP202216 is as safe as the comparator and non-GM reference varieties tested, and no post-market monitoring of food/feed is considered necessary. In the case of accidental release of viable maize DP202216 grains into the environment, this would not raise environmental safety concerns. The post-market environmental monitoring plan and reporting intervals are in line with the intended uses of maize DP202216. The GMO Panel concludes that maize DP202216 is as safe as its comparator and the tested non-GM reference varieties with respect to potential effects on human and animal health and the environment.

Epigenetics and plant hormone dynamics - a functional and methodological perspective.

Plant hormones, pivotal regulators of plant growth, development, and response to environmental cues, have recently emerged as central modulators of epigenetic processes governing gene expression and phenotypic plasticity. This review addresses the complex interplay between plant hormones and epigenetic mechanisms, highlighting the diverse methodologies that have been harnessed to decipher these intricate relationships. We present a comprehensive overview to understand how phytohormones orchestrate epigenetic modifications, shaping plant adaptation and survival strategies. Conversely, we explore how epigenetic regulators ensure hormonal balance and regulate the signalling pathways of key plant hormones. Furthermore, our investigation includes a search for novel genes that are regulated by plant hormones under the control of epigenetic processes. Our review offers a contemporary overview of the epigenetic-plant hormone crosstalk, emphasizing its significance in plant growth, development, and potential agronomical applications.

Non-invasive Assay for Chlorophyll Biosynthesis Kinetics Determination during Early Stages of Arabidopsis De-etiolation.

Chlorophyll biosynthesis is a hallmark of de-etiolation, one of the most dramatic stages in the plant life cycle. The tightly controlled and highly dynamic process of chlorophyll biosynthesis is triggered during the shift from the dark to the light in flowering plants. At the moment when etiolated seedlings are exposed to the first traces of sunlight, rapid (in order of seconds) conversion of protochlorophyllide into chlorophyllide is mediated by unique light-accepting protein complexes, leading via subsequent metabolic steps to the production of fully functional chlorophyll. Standard techniques for chlorophyll content analysis include pigment extraction from detached plant tissues, which does not apply to studying such fast processes. To investigate chlorophyll kinetics in vivo with high accuracy and spatiotemporal resolution in the first hours after light-induced de-etiolation, an instrument and protocol were developed. Here, we present a detailed procedure designed for statistically robust quantification of chlorophyll in the early stages of Arabidopsis de-etiolation.

Assessment of genetically modified maize DP23211 for food and feed uses, under Regulation (EC) No 1829/2003 (application EFSA-GMO-NL-2019-163).

Genetically modified maize DP23211 was developed to confer control of certain coleopteran pests and tolerance to glufosinate-containing herbicide. These properties were achieved by introducing the pmi, mo-pat, ipd072Aa and DvSSJ1 expression cassettes. The molecular characterisation data and bioinformatic analyses do not identify issues requiring food/feed safety assessment. None of the identified differences in the agronomic/phenotypic and compositional characteristics tested between maize DP23211 and its conventional counterpart needs further assessment, except for those in levels of histidine, phenylalanine, magnesium, phosphorus and folic acid in grain, which do not raise safety and nutritional concerns. The GMO Panel does not identify safety concerns regarding the toxicity and allergenicity of the IPD072Aa, PAT and PMI proteins and the DvSSJ1 dsRNA and derived siRNAs newly expressed in maize DP23211, and finds no evidence that the genetic modification impacts the overall safety of maize DP23211. In the context of this application, the consumption of food and feed from maize DP23211 does not represent a nutritional concern in humans and animals. Therefore, no post-market monitoring of food/feed is considered necessary. In the case of accidental release of viable maize DP23211 grains into the environment, this would not raise environmental safety concerns. The post-market environmental monitoring plan and reporting intervals are in line with the intended uses of maize DP23211. The GMO Panel concludes that maize DP23211 is as safe as its conventional counterpart and the tested non-GM reference varieties with respect to potential effects on human and animal health and the environment.

Assessment of genetically modified maize DP915635 for food and feed uses, under regulation (EC) No 1829/2003 (application EFSA-GMO-NL-2020-172).

Genetically modified maize DP915635 was developed to confer tolerance to glufosinate herbicide and resistance to corn rootworm pests. These properties were achieved by introducing the ipd079Ea, mo-pat and pmi expression cassettes. The molecular characterisation data and bioinformatic analyses do not identify issues requiring food/feed safety assessment. None of the identified differences in the agronomic/phenotypic and compositional characteristics tested between maize DP915635 and its conventional counterpart needs further assessment, except for the levels of crude protein in forage, which does not raise nutritional and safety concerns. The GMO Panel does not identify safety concerns regarding the toxicity and allergenicity of the IPD079Ea, PAT and PMI proteins expressed in maize DP915635. The GMO Panel finds no evidence that the genetic modification impacts the overall safety of maize DP915635. In the context of this application, the consumption of food and feed from maize DP915635 does not represent a nutritional concern in humans and animals. The GMO Panel concludes that maize DP915635 is as safe as the conventional counterpart and non-GM maize varieties tested, and no post-market monitoring of food/feed is considered necessary. In the case of accidental release of viable maize DP915635 grains into the environment, this would not raise environmental safety concerns. The post market environmental monitoring plan and reporting intervals are in line with the intended uses of maize DP915635. The GMO Panel concludes that maize DP915635 is as safe as its conventional counterpart and the tested non-GM maize varieties with respect to potential effects on human and animal health and the environment.

Assessment of genetically modified maize MON 810 for renewal authorisation under Regulation (EC) No 1829/2003 (dossier GMFF-2022-9450).

Following the submission of dossier GMFF-2022-9450 under Regulation (EC) No 1829/2003 from Bayer Agriculture BV, the Panel on Genetically Modified Organisms of the European Food Safety Authority was asked to deliver a scientific risk assessment on the data submitted in the context of the renewal of authorisation application for the insect protected genetically modified maize MON 810, for food and feed uses (including pollen), excluding cultivation within the European Union. The data received in the context of this renewal application contained post-market environmental monitoring reports, an evaluation of the literature retrieved by a scoping review, additional studies performed by or on behalf of the applicant and updated bioinformatics analyses. The GMO Panel assessed these data for possible new hazards, modified exposure or new scientific uncertainties identified during the authorisation period and not previously assessed in the context of the original application. Under the assumption that the DNA sequence of the event in maize MON 810 considered for renewal is identical to the sequence of the originally assessed event, the GMO Panel concludes that there is no evidence in dossier GMFF-2022-9450 for new hazards, modified exposure or scientific uncertainties that would change the conclusions of the original risk assessment on maize MON 810.

Assessment of genetically modified cotton COT102 for food and feed uses, under Regulation (EC) No 1829/2003 (application EFSA-GMO-DE-2017-141).

Genetically modified cotton COT102 was developed to confer resistance against several lepidopteran species. The molecular characterisation data and bioinformatic analyses do not identify issues requiring food/feed safety assessment. None of the differences in the agronomic-phenotypic and compositional characteristics between cotton COT102 and its non-GM comparator needs further assessment, except for levels of acid detergent fibre, which do not raise safety or nutritional concerns. The GMO Panel does not identify safety concerns regarding the toxicity and allergenicity of the Vip3Aa19 and APH4 proteins as expressed in cotton COT102 and finds no evidence that the genetic modification would change the overall allergenicity of cotton COT102. In the context of this application, the consumption of food and feed from cotton COT102 does not represent a nutritional concern for humans and animals. The GMO Panel concludes that cotton COT102 is as safe as the non-GM comparator and non-GM cotton varieties tested, and no post-market monitoring of food/feed is considered necessary. In the case of accidental release of viable cotton COT102 seeds into the environment, this would not raise environmental safety concerns. The post-market environmental monitoring plan and reporting intervals are in line with the intended uses of cotton COT102. The GMO Panel concludes that cotton COT102 is as safe as its non-GM comparator and the tested non-GM cotton varieties with respect to potential effects on human and animal health and the environment.

Assessment of genetically modified maize Bt11 × MIR162 × MIR604 × MON 89034 × 5307 × GA21 and 30 subcombinations, for food and feed uses, under Regulation (EC) No 1829/2003 (application EFSA-GMO-DE-2018-149).

Genetically modified maize Bt11 × MIR162 × MIR604 × MON 89034 × 5307 × GA21 was developed by crossing to combine six single events: Bt11, MIR162, MIR604, MON 89034, 5307 and GA21, the GMO Panel previously assessed the 6 single maize events and 27 out of the 56 possible subcombinations and did not identify safety concerns. No new data on the single maize events or the assessed subcombinations were identified that could lead to modification of the original conclusions on their safety. The molecular characterisation, comparative analysis (agronomic, phenotypic and compositional characteristics) and the outcome of the toxicological, allergenicity and nutritional assessment indicate that the combination of the single maize events and of the newly expressed proteins in the six-event stack maize does not give rise to food and feed safety and nutritional concerns. The GMO Panel concludes that six-event stack maize, as described in this application, is as safe as the conventional counterpart and non-GM maize varieties tested, and no post-market monitoring of food/feed is considered necessary. In the case of accidental release of viable six-event stack maize grains into the environment, this would not raise environmental safety concerns. The GMO Panel assessed the likelihood of interactions among the single events in 29 of the maize subcombinations not previously assessed and covered by the scope of this application and concludes that these are expected to be as safe as the single events, the previously assessed subcombinations and the six-event stack maize. The post-market environmental monitoring plan and reporting intervals are in line with the intended uses of maize Bt11 × MIR162 × MIR604 × MON 89034 × 5307 × GA21. The GMO Panel concludes that six-event stack maize and the 30 subcombinations covered by the scope of the application are as safe as its conventional counterpart and the tested non-GM maize varieties with respect to potential effects on human and animal health and the environment.

Assessment of genetically modified oilseed rape MS8, RF3 and MS8 × RF3 for renewal authorisation under Regulation (EC) No 1829/2003 (application EFSA-GMO-RX-024).

Following the submission of application EFSA-GMO-RX-024 under Regulation (EC) No 1829/2003 from BASF Agricultural Solutions Seed US LLC, the Panel on Genetically Modified Organisms of EFSA was asked to deliver a scientific risk assessment on the data submitted in the context of the renewal of authorisation application for the herbicide tolerant genetically modified oilseed rape MS8, RF3 and MS8 × RF3, for food and feed uses, excluding cultivation within the European Union. The data received in the context of this renewal application contained post-market environmental monitoring reports, a systematic search and evaluation of literature, updated bioinformatic analyses, and additional documents or studies performed by or on behalf of the applicant. The GMO Panel assessed these data for possible new hazards, modified exposure or new scientific uncertainties identified during the authorisation period and not previously assessed in the context of the original application. Under the assumption that the DNA sequences of the events in oilseed rape MS8, RF3 and MS8 × RF3 considered for renewal are identical to the sequences of the originally assessed events, the GMO Panel concludes that there is no evidence in renewal application EFSA-GMO-RX-024 for new hazards, modified exposure or scientific uncertainties that would change the conclusions of the original risk assessment on oilseed rape MS8, RF3 and MS8 × RF3.

iReenCAM: automated imaging system for kinetic analysis of photosynthetic pigment biosynthesis at high spatiotemporal resolution during early deetiolation.

Seedling de-etiolation is one of the key stages of the plant life cycle, characterized by a strong rearrangement of the plant development and metabolism. The conversion of dark accumulated protochlorophyllide to chlorophyll in etioplasts of de-etiolating plants is taking place in order of ns to µs after seedlings illumination, leading to detectable increase of chlorophyll levels in order of minutes after de-etiolation initiation. The highly complex chlorophyll biosynthesis integrates number of regulatory events including light and hormonal signaling, thus making de-etiolation an ideal model to study the underlying molecular mechanisms. Here we introduce the iReenCAM, a novel tool designed for non-invasive fluorescence-based quantitation of early stages of chlorophyll biosynthesis during de-etiolation with high spatial and temporal resolution. iReenCAM comprises customized HW configuration and optimized SW packages, allowing synchronized automated measurement and analysis of the acquired fluorescence image data. Using the system and carefully optimized protocol, we show tight correlation between the iReenCAM monitored fluorescence and HPLC measured chlorophyll accumulation during first 4h of seedling de-etiolation in wild type Arabidopsis and mutants with disturbed chlorophyll biosynthesis. Using the approach, we demonstrate negative effect of exogenously applied cytokinins and ethylene on chlorophyll biosynthesis during early de-etiolation. Accordingly, we identify type-B response regulators, the cytokinin-responsive transcriptional activators ARR1 and ARR12 as negative regulators of early chlorophyll biosynthesis, while contrasting response was observed in case of EIN2 and EIN3, the components of canonical ethylene signaling cascade. Knowing that, we propose the use of iReenCAM as a new phenotyping tool, suitable for quantitative and robust characterization of the highly dynamic response of seedling de-etiolation.

Risk assessment of additional information on maize MIR162.

The European Commission requested the Panel on Genetically Modified Organisms of the European Food Safety Authority (EFSA GMO Panel) to assess new scientific information on maize MIR162, and to indicate whether the previous conclusions on the safety of maize MIR162 as a single event and as a part of stacked events remain valid. The new information is included in a European patent that reports a decrease in male fertility in some MIR162 inbred lines, pointing to a potential link between such decrease and the Vip3 protein expressed by maize MIR162. The EFSA GMO Panel evaluated the data provided by the patent owner and found scarce support for a causal link between Vip3 and decreased fertility. The general hypothesis of an association between event MIR162 and altered fertility could not be confirmed. The EFSA GMO Panel conducted the safety assessment based on the conservative assumption that such an association exists. The EFSA GMO Panel concluded that a decrease in male fertility would have no impact on the previous conclusions on maize MIR162 and stacked events containing MIR162.

Hormone-regulated expansins: Expression, localization, and cell wall biomechanics in Arabidopsis root growth.

Expansins facilitate cell expansion by mediating pH-dependent cell wall (CW) loosening. However, the role of expansins in controlling CW biomechanical properties in specific tissues and organs remains elusive. We monitored hormonal responsiveness and spatial specificity of expression and localization of expansins predicted to be the direct targets of cytokinin signaling in Arabidopsis (Arabidopsis thaliana). We found EXPANSIN1 (EXPA1) homogenously distributed throughout the CW of columella/lateral root cap, while EXPA10 and EXPA14 localized predominantly at 3-cell boundaries in the epidermis/cortex in various root zones. EXPA15 revealed cell-type-specific combination of homogenous vs. 3-cell boundaries localization. By comparing Brillouin frequency shift and AFM-measured Young's modulus, we demonstrated Brillouin light scattering (BLS) as a tool suitable for non-invasive in vivo quantitative assessment of CW viscoelasticity. Using both BLS and AFM, we showed that EXPA1 overexpression upregulated CW stiffness in the root transition zone (TZ). The dexamethasone-controlled EXPA1 overexpression induced fast changes in the transcription of numerous CW-associated genes, including several EXPAs and XYLOGLUCAN:XYLOGLUCOSYL TRANSFERASEs (XTHs), and associated with rapid pectin methylesterification determined by in situ Fourier-transform infrared spectroscopy in the root TZ. The EXPA1-induced CW remodeling is associated with the shortening of the root apical meristem, leading to root growth arrest. Based on our results, we propose that expansins control root growth by a delicate orchestration of CW biomechanical properties, possibly regulating both CW loosening and CW remodeling.

Assessment of genetically modified maize GA21 × T25 for food and feed uses, under Regulation (EC) No 1829/2003 (application EFSA-GMO-DE-2016-137).

Genetically modified maize GA21 × T25 was developed by crossing to combine two single events: GA21 and T25. The GMO Panel previously assessed the two single maize events and did not identify safety concerns. No new data on the single maize events were identified that could lead to modification of the original conclusions on their safety. The molecular characterisation, comparative analysis (agronomic, phenotypic and compositional characteristics) and the outcome of the toxicological, allergenicity and nutritional assessment indicate that the combination of the single maize events and of the newly expressed proteins in maize GA21 × T25 does not give rise to food and feed safety and nutritional concerns. The GMO Panel concludes that maize GA21 × T25, as described in this application, is as safe as its conventional counterpart and the non-GM reference varieties tested, and no post-market monitoring of food and feed is considered necessary. In the case of accidental release of viable maize GA21 × T25 grains into the environment, this would not raise environmental safety concerns. The post-market environmental monitoring plan and reporting intervals are in line with the intended uses of maize GA21 × T25. Post-market monitoring of food and feed is not considered necessary. The GMO Panel concludes that maize GA21 × T25 is as safe as its conventional counterpart and the non-GM reference varieties tested, with respect to potential effects on human and animal health and the environment.