Napier, J. A.

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FIRST CUTA Field Day for Gene-Edited Brassicasand Crop ImprovementJohnathan A. Napier*A new report in this issue from a U.K. plant science group offers a welcome path forward for crop researchin the field.Similar to other branches of life sciences, plant research-ers were quick to recognize the transformative nature ofCRISPR-Cas9–mediated gene editing, and this technol-ogy (along with its ever-expanding repertoire of variantsand enhancements) has been gleefully embraced by theinternational plant sciences community. CRISPR’s flexi-ble and user-friendly technology is seen as central to ac-celerating plant breeding and crop improvement, whichin turn will underpin global food security.In particular, meeting the targets of the United Nations2015 Sustainable Development Goals—specificallySDG2’s headline aim of ‘‘zero hunger’’ (or the full goal,‘‘end hunger, achieve food security and improved nutri-tion and promote sustainable agriculture’’) by 2030—isa daunting task that gets harder every day. So, fromone perspective, CRISPR technology could be seen asarriving just in the nick of time. Certainly, it will play avital role in developing new crops that are better adaptedto our changing climates, less impactful on the environ-ment, and deliver improved nutrition.1However, although the adoption of CRISPR tools isnow ubiquitous in molecular plant sciences research, pro-pelling advances in our basic understanding of many as-pects of crop physiology and stress tolerance, there is stilla gulf between these laboratory-based findings and whatmight be termed ‘‘the real world.’’ This is important, be-cause the closeted research environments we grow ourpampered modified plants in bear no resemblance to theunpredictable and increasingly variable climates cropsroutinely face in the field. Ultimately, if we want ourplant research to lead to some positive societal outcome,making a contribution to SDG2, then we need to discoverwhether genetic changes engineered in the laboratory willactually work in the field. Will they be robust enough tocontinue to deliver benefits, even under a gauntlet of en-vironmental factors?For those outside the plant sciences sphere, it mightseem logical if not mandatory for laboratory discoveriesto transition to field evaluation, but this is where wider is-sues (such as the regulation of transgenic crops) comeinto play. These are themselves something of a hot (ge-netically modified [GM]) potato. And although nowadaysit seems almost obligatory to conclude the write-up ofany new discovery as being a ‘‘game-changer’’ in deliv-ering food security, etc., in reality, very few fundamentalstudies seem prepared to put their money where their (orothers) mouths might be and confirm the potential of theirresearch by carrying out field trials. This is crucial—youcannot eat potential!Now, of course there are many reasons for research notto transition from the glasshouse to the field, includingless funding for what is still viewed dismissively as ‘‘ap-plied’’ research, as well as regional differences in howstraightforward (or not) it is to carry out an environmentalrelease of plants that have been genetically modified.Moreover, there is a lack of consistency, at least fromvarious regulatory agencies, as to whether or not genomeediting should be classified as either GM or a form of mu-tagenesis (or both). This is a particular barrier to transla-tion in the European Union (EU), which has some of theleast enabling regulations when it comes to genetic mod-ification. It was surprising and frankly disheartening thatPlant Sciences Department, Rothamsted Research, Harpenden, United Kingdom.*Address correspondence to: Johnathan A. Napier, Plant Sciences Department, Rothamsted Research, Harpenden, Herts AL5 2JQ, United Kingdom, E-mail:johnathan.napier@rothamsted.ac.ukThe CRISPR JournalVolume 4, Number 3, 2021ª Mary Ann Liebert, Inc.DOI: 10.1089/crispr.2021.29130.kad307Downloaded by BBSRC Bioscience IT Services Trial Access from www.liebertpub.com at 07/05/21. For personal use only. a review published last year listing all known examples ofgenome-editing field trials produced a rather short list,the bulk of which were run in China on rice.2 Clearlythere is a bottleneck in the translation of much cutting-edge plant sciences research.Field EffectBecause of (or perhaps despite) all the mentioned reasons,a new article by Neequaye et al.3 in Lars Østergaard’sgroup at the John Innes Centre, in Norwich, United King-dom, in this issue of The CRISPR Journal should beapplauded, for the authors have opted to take that roadless traveled and evaluate their CRISPR-Cas9 editedBrassica oleracea plants in the field.In this study, Neequaye et al. used gene editing to gen-erate loss-of-function mutant alleles of the transcriptionfactor MYB28, which is a key regulator of aliphatic glu-cosinolate biosynthesis. In doing so, the authors hopedto change the wider balance of the metabolites presentwithin the plant, to better understand how to modulatethese health-beneficial compounds without impactingcrop growth. Gene editing in plants can be made morecomplicated by both polyploidy and neofunctionaliza-tion, meaning that the authors had to seek the plantswith useful (disruptive) edits in the different MYB28paralogues present in B. oleracea. Having identifiedmutations in two of the three MYB28 paralogues, thestage was set for further investigation: at this point, thestudy diverges from the majority of CRISPR-mediatedmutagenesis stories by opting to take the evaluation ofthe plants into the field.As noted earlier, environmental release of gene-editedplants is subject to regulation, the complexity of which is de-pendent on jurisdiction defined by location (national and re-gional). In the United Kingdom, a previous field release in2018 of CRISPR-edited Camelina was classified by theU.K. regulator as being outside the scope of the Europeanlegal definition of a genetically modified organism, assuch, these plants did not need approval under the mecha-nism used to approve GM field trials. However, during thatfield release in 2018, the European Court of Justice (ECJ)ruled that gene editing was a form of genetic modification,at least in the context of the definition first used by the EUin 2001, eliciting strong reactions from many quarters.4The ECJ ruling of July 25, 2018, trumped the earlierU.K. ruling as to the status of gene editing, meaningthat these edited Camelina metaphorically transformedinto GM plants overnight.5 Thus, Neequaye and collea-gues would need to apply for ‘‘Ministerial consent’’ togrow their edited B. oleracea plants in the field, sincethey were now considered to be GM. This was eventhough the authors clearly demonstrated that the trans-gene carrying the Cas9, gRNAs, and selectable markerwas absent from their plants. All that remained wasthe tiny edits in the MYB28 genes that they hadengineered.FIG. 1. Environmental release and field trialing of GE and GM crops in the United Kingdom. (A) Plots at theRothamsted experimental farm of GE, GM, and GE+GM Camelina, June 2020. Note that GE lines are classified as GMand, as such, are grown within one of the dedicated GM trial areas on the farm. Right panel—large plot of fullyflowering GM Camelina on the Rothamsted experimental farm, June 2018. The profound difference betweencontrolled glasshouse conditions and those in the field can be exemplified by the variable environmentalconditions and, for example, the presence of insects (B). It is for these reasons it is vital to validate laboratory resultsaimed at crop improvement in the field. GE, gene edited; GM, genetically modified.308 NAPIERDownloaded by BBSRC Bioscience IT Services Trial Access from www.liebertpub.com at 07/05/21. For personal use only. For many, obtaining such consent would be viewed astoo cumbersome—the process takes months and requiresmandatory public disclosure of the intention to run aGM field trial, which can then generate a response fromanti-GM campaign groups. Similarly, there is the obviousrequirement of not only having access to a suitable exper-imental farm (or similar) but also a commitment to ac-tually perform experiments in the field, which is quitedifferent from the pristine laboratory environment (seeFig. 1 for visual example).It is to the immense credit of the John Innes group thatthey actively embraced the transition from laboratory tofield, validating their hypothesis on the role of MYB28 onthe regulation of glucosinate content in Brassicas, and alsoobtaining a comprehensive RNAseq data sets for field-grown WT and myb28 plants. Perhaps most importantly,it confirmed the commitment of U.K. plant scientists to con-tinue to deliver research outcomes that are both academi-cally exciting and of wider relevance to society.Although the United Kingdom is currently adheringto the 2018 ECJ ruling, exit from membership of theEU in January 2021 presented an opportunity to divergefrom the assertion that gene editing is a form of GM.To that end, the U.K. government recently concluded a10-week public consultation on the future regulation ofthe new genetic technologies, with the outcome eagerlyawaited this summer.In the future, studies such as that highlighted here willhopefully not have so many impediments in the transla-tion of their fundamental research. By reducing that bur-den, we might break the bottleneck and see many morefield trials as researchers get to test their innovations inthe real world. This can only be a good thing, especiallyif we want to use the phenomenal power of gene editingto help meet our global challenges.References1. Van Der Straeten D, Bhullar NK, De Steur H, et al. Multiplyingthe efficiency and impact of biofortification through metabolicengineering. Nat Commun. 2020;11:5203. DOI: 10.1038/s41467-020-19020-4.2. Metje-Sprink J, Sprink T, Hartung F. Genome-edited plants in the field.Curr Opin Biotechnol. 2020;61:1–6. DOI: 10.1016/j.copbio.2019.08.007.3. Neequaye M, Stavnstrup S, Harwood W, et al. CRISPR-Cas9-mediated geneediting of MYB28 genes impair glucoraphanin accumulation of Brassicaoleracea in the field. CRISPR J 2021;4:416–426.4. Barrangou R. CRISPR craziness: A response to the EU Court ruling. CRISPR J2018;1:251–252. DOI: 10.1089/crispr.2018.29025.edi.5. Faure JD, Napier JA. Europe’s first and last field trial of gene-edited plants?eLife 2018;7:e42379. DOI: 10.7554/eLife.42379.DOI: 10.1089/crispr.2021.29128.smaCRISPR and Chromothripsis: Proceed with CautionStephanie Mack* and I. Alasdair Russell*A new study in Nature Genetics is a timely reminder of the need to address on- and off-target genomerearrangements in CRISPR gene editing.CRISPR-Cas9 has revolutionized all aspects of biology,making it easier and faster to generate authentic modelsof disease through its precise programmable nuclease ac-tivity. Recently, attention has turned to the clinic, wherethe technology is tackling several diseases such as b thal-assemia and sickle cell disease (SCD).1 As with all ther-apies, specificity and safety are paramount, and are areasof intense research.2 To date, most efforts have focusedon spurious editing at unintended sites in the genome. Awealth of literature is dedicated to identifying3,4 andmitigating5–10 these off-target edits. Recent observationshave extended spurious editing events to the target siteitself,11 again prompting careful examination of editingoutcome.Cancer Research UK Cambridge Institute, University of Cambridge, Cambridge, United Kingdom.*Address correspondence to: Stephanie Mack, PhD, or Alasdair Russell, PhD, Cancer Research UK Cambridge Institute, University of Cambridge, Cambridge CB2 0RE,United Kingdom, Email: Stephanie.Mack@cruk.cam.ac.uk or Alasdair.Russell@cruk.cam.ac.ukCRISPR AND CHROMOTHRIPSIS: PROCEED WITH CAUTION 309Downloaded by BBSRC Bioscience IT Services Trial Access from www.liebertpub.com at 07/05/21. For personal use only. 

A Field Day for Gene-Edited Brassicas and Crop Improvement

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A Field Day for Gene-Edited Brassicas and Crop Improvement

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