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Genetically Modified Foods a Critical Review of Their Promise and Problems

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INTRODUCTION

Genetic modification (GM) is the area of biotechnology which concerns itself with the manipulation of the genetic cloth in living organisms, enabling them to perform specific functions. one , 2 The primeval concept of modification for domestication and consumption of plants dates back ∼10,000 years where human being ancestors practiced "selective breeding" and "bogus option" – the Darwinian-coined terms broadly referring to selection of parent organisms having desirable traits (eg: hardier stems) and convenance them for propagating their traits. The about dramatic alteration of plant genetics using these methods occurred through artificial selection of corn – from a weedy grass possessing tiny ears and few kernels (teosinte; earliest recorded growth: central Balsas river valley, southern United mexican states 6300 years ago) to the current cultivars of edible corn and maize plants (Doebley et al., 2016, Fig 1). The use of similar techniques has also been reported to derive current variants of apples, broccoli and bananas unlike from their bequeathed plant forms which are vastly desirable for human consumption. 3

Figure 1. The evolution of modern corn/maize (height) from teosinte plants (bottom) by repetitive selective breeding over several generations. [Sources: 50 (top figure), 51 (bottom figure)].

The developments leading to modern genetic modification took place in 1946 where scientists beginning discovered that genetic material was transferable between different species. This was followed by Dna double helical construction discovery and conception of the central dogma – the transcription of Deoxyribonucleic acid to RNA and subsequent translation into proteins – by Watson and Crick in 1954. Consequently, a serial of breakthrough experiments by Boyer and Cohen in 1973, which involved "cutting and pasting" Deoxyribonucleic acid between different species using restriction endonucleases and Deoxyribonucleic acid ligase – "molecular pair of scissors and glue" (Rangel, 2016) successfully engineered the world'due south beginning GM organism. In agronomics, the get-go GM plants – antibiotic resistant tobacco and petunia – were successfully created in 1983 by three independent research groups. In 1990, China became the first state to commercialise GM tobacco for virus resistance. In 1994, the Flavr Savr love apple (Calgene, U.s.) became the starting time ever Nutrient and Drug Assistants (FDA) approved GM plant for human consumption. This tomato plant was genetically modified past antisense technology to interfere with polygalacturonase enzyme product, consequently causing delayed ripening and resistance to rot. iv Since and then, several transgenic crops received approvals for large scale human product in 1995 and 1996. Initial FDA-approved plants included corn/maize, cotton and potatoes (Bacillus thuringiensis (Bt) gene modification, Ciba-Geigy and Monsanto) canola (Calgene: increased oil production), cotton (Calgene: bromoxynil resistance) and Roundup Ready soybeans (Monsanto: glyphosate resistance), 4 Fig 2). Currently, the GM crop pipeline has expanded to cover other fruits, vegetables and cereals such as lettuce, strawberries, eggplant, sugarcane, rice, wheat, carrots etc. with planned uses to increment vaccine bioproduction, nutrients in animal feed every bit well as confer salinity and drought resistant traits for plant growth in unfavourable climates and environment. 4 , 2

Effigy 2. A timeline of events leading to the current GM crop era.

Since their commercialisation, GM crops have been benign to both economy and the environment. The global food crop yield (1996–2013) has increased by > 370 one thousand thousand tonnes over a relatively pocket-sized acreage area. 2 Furthermore, GM crops have been recorded to reduce environmental and ecological impacts, leading to increases in species diversity. Information technology is therefore unsurprising that GM crops take been commended by agricultural scientists, growers and almost environmentalists worldwide.

Nevertheless, advancements in GM crops have raised significant questions of their safety and efficacy. The GM seed industry has been plagued with problems related to human being health and insect resistance which have seriously undermined their benign furnishings. Moreover, poor science communication by seed companies, a significant lack of safety studies and current mistrust regarding GMOs have only compounded problems. These have led many countries, peculiarly the European Union and Heart East to implement partial or full restrictions on GM crops. GM agriculture is now widely discussed in both positive and negative frames, and currently serves as a hotbed of contend in public and policymaking levels.

CHALLENGES IN COMMERCIAL AGRICULTURE

The agriculture industry has been valued at an estimated United states of america$ 3.2 trillion worldwide and accounts for a large share of the GDP and employment in developing and underdeveloped nations. 5 For instance: Agriculture contributes only ane.4% towards the Gross domestic product and 1.62% of the workforce in United states in comparing with Due south Asian regions, where it contributes 18.6% towards the Gdp and l% of the workforce. 6 However, despite employing nearly 1 in v people worldwide (19% of the globe's population), 7 the agronomics industry is projected to endure significant global setbacks (population growth, pest resistance and brunt on natural resources) by 2050, which has been elaborated farther in this department.

Explosive Population Growth

The Food and Agricultural Organization projects the global population to abound to approximately 9.7 billion by 2050 – a near l% increase from 2013 – and farther to an estimated 11bn past 2100. Electric current agronomical practices alone cannot sustain the globe population and eradicate malnutrition and hunger on a global scale in the future. Indeed, the FAO also estimates that despite a significant reduction in global hunger, 653 mn people will withal be undernourished in 2030. 8 Additionally, Ray et al. and other studies depict the top four global crops (soybean, maize, wheat and rice) are increasing at ane.0%, 0.nine%, 1.6% and 1.3% per annum respectively– approximately 42%, 38%, 67% and 55% lower than the required growth rate (ii.4%/annum) to sustain the global population in 2050. 9 Compounded with other problems such as improved nutritional standards in the burgeoning lower-heart form and projected loss in arable country (from 0.242 ha/person in 2016 to 0.18 ha/person in 2050) ii due to degradation and accelerated urbanization, rapid world population expansion will increase demand for food resource.

Pests and Crop Diseases

Annual crop loss to pests alone account for 20–xl% of the global crop losses. In terms of economical value, tackling ingather diseases and epidemics and invasive insect problem costs the agriculture industry approximately $290 mn annually. 8 Currently, major epidemics go on to plague commercial agriculture. It has been projected that crop disease and pest incidences are expanding in a poleward direction (2.seven km annually), 10 indicated by coffee leaf rust and wheat rust outbreaks in Primal America. These incidences have largely been attributed to an amalgamation of globalisation leading to increased establish, pest and disease movement, increase in disease vectors, climate change and global warming. 8

While integrated pest management and prevention techniques somewhat mitigate the pest problem, they are insufficient to tackle the transboundary crop-demics. The epidemiology of the Panama illness (or Panama wilt), caused by the soil fungus Fusarium oxysporum f.sp. cubense (Foc) 11 provides solid evidence in this regard. Since the early-mid 1990s the Tropical Race-4 (TR4) strain, a unmarried pathogen Foc fungus clone, has significantly crippled the global banana industry. In 2013, the Mindanao Banana Farmers and Exporters association (in Philippines) reported infection in 5900 hectares of bananas, including 3000 hectares that were abased. In Mozambique, symptomatic plants currently account for >20% of total banana plantations (570,000 out two.5m) since the reporting of TR4 in 2015. Additionally, TR4 losses take cost Taiwanese, Malaysian, and Indonesian economies a combined estimate of US$ 388.4 mn. 12 Therefore, an alarming increase in transboundary crop and pest diseases take broad environmental, social and economic impacts on farmers and threaten nutrient security.

Burden on Natural Resources

The FAO'southward 2050 projections advise projected natural resource scarcities for crop care. viii Despite overall agronomical efficiency, unsustainable competition has intensified due to urbanisation, population growth, industrialisation and climate alter. Deforestation for agricultural purposes has driven 80% of the deforestation worldwide. In tropical and subtropical areas where deforestation is still widespread, agricultural expansion accounted for loss of 7 1000000 hectares per annum of natural forests betwixt 2000–2010. eight Additionally, water withdrawals for agronomics accounted for seventy% of all withdrawals, seriously depleting natural water resource in many countries. This has peculiarly been observed in low rainfall regions, such equally Middle East, North Africa and Central Asia where water for agriculture accounts for lxxx–90% 8 of the total water withdrawal. These trends are predicted to continue well into the 21st century and therefore increase the brunt of natural resource consumption globally.

SOLUTIONS PROVIDED BY GM CROPS

GM crops have been largely successful in mitigating the above major agriculture challenges while providing numerous benefits to growers worldwide. From 1996–2013, they generated $117.6 bn over 17 years in global farm income benefit alone. The global yearly cyberspace income increased past 34.three% in 2010–2012. 13 , xiv Furthermore, while increasing global yield by 22%, GM crops reduced pesticide (active ingredient) usage by 37% and environmental impact (insecticide and herbicide use) by 18%. xv To achieve the same yield standards more than 300 million acres of conventional crops would have been needed, which would accept further compounded current environmental and socioeconomic bug in agriculture. 2

To further emphasise the impact of GM crops on economies: two example studies – GM Canola (Australia) and GM cotton (India) – have been highlighted in this review.

GM Cotton wool (Republic of india)

In India, cotton fiber has served as an important fibre and textile raw material and plays a vital role in its industrial and agronomical economy. Nearly 8 million farmers, most of them small and medium (having less than 15 acres of farm size and an average of iii–4 acres of cotton fiber holdings) depend on this crop for their livelihood. In 2002, Monsanto-Mahyco introduced Bollgard-I, India'southward first GM cotton hybrid containing Cry1Ac-producing Bacillus thuringiensis (Bt) genes for controlling the pink bollworm (P. gossypiella) pest. 16 Initially, only 36% of the farmers adopted the new crop nevertheless this statistic soon grew to 46% in 200417 after Bt-cotton was approved nationwide. This was followed by approval and launch of Bollgard-II (a two-toxin Cry1Ac and Cry2Ab-producing Bt-pyramid conferring resistance to bollworm) by Monsanto-Mahyco, which subsequently enhanced Bt-cotton adoption among Indian cotton growers (Fig 3).

Figure 3. Adoption of GM canola (height) and GM cotton (bottom) in Australia and India respectively. The primary vertical centrality shows the total acreage of cotton and canola forth with the proportion of GM and non-GM crops grown per year, while the secondary horizontal axis depicts the per centum of GM ingather adoption among farmers and growers per year. (Sources: 22 , xviii ).

Despite controversies, Bt-cotton's implementation has largely benefited Indian farmers and agricultural economy. Bt-cotton fiber has increased profits and yield by Rs. 1877 per acre (US$38) and 126 kg/acre of farmland respectively, 50% and 24% more than profit and yield by conventional cotton. This translates to a net increase of Bt-cotton fiber growers' annual consumption expenditures past 18% (Rs. xv,841/US$321) compared to non-adapters, highlighting improved living standards. 17 Bt-cotton adoption has also resulted in a 22-fold increase in India'southward agri-biotech industry due to an unprecedented 212-fold rise in plantings from 2002–2011 (accounting for ∼30% of global cotton farmland), surpassing Red china and making it a globe leading grower and exporter. 7 1000000 out of the 8 million farmers (88%) are growing Bt-cotton fiber annually. Cotton crop yields take also increased 31% while conversely insecticide usage has more than halved (46% to 21%) enhancing India's cotton income by US$11.9 bn. 18 Therefore, Bt-cotton has resulted in economic prosperity amid Bt-cotton growers, with 2002–xi often being called a white gold period for Republic of india'due south GM cotton industry.

GM Canola (Australia)

Canola in Commonwealth of australia is grown as a break crop, providing farmers a profitable alternative along with rotational benefits from continuous cereal crop phases and their related weed/pest mechanisms. Other benefits include broadleaf weed and cereal root disease command and better successive cereal crop growth. It is most prominently grown in Western Australia (WA), where it accounts for 400–800,000 ha of farmland and is the near successful of iv break crops (oat, lupin, canola and field pea). From 2002–2007, Canola production in WA alone deemed for a yield of 440 mn tonnes valued at A$200mn. 19 However Canola has been a high risk ingather and particularly susceptible to blackleg disease (caused by fungus Leptosphaeria maculans), and weeds such as charlock (Sinapis arvensis), wild radish (Raphanus raphanistrum L) and Buchan (Hirschfeldia incana (Fifty.) Lagr.-Foss) which increase anti-nutritional chemical compound content and composition in canola oil, degrading quality. 20

In 2008–09, two herbicide resistant GM canola varieties: Roundup Set® (Monsanto) and InVigor® (Bayer Cropsciences) were introduced in Australia. Roundup Prepare® contained cistron variants with altered EPSP synthase (5-enolpyruvylshikimate-3-phosphate) alterations along with a glyphosate oxidoreductase gene making it glyphosate resistant. Information technology gained OGTR approving after trials showed its ecology impact was less than one-half (43%) of triazine tolerant canola varieties 21 , 19 and remains the only OGTR-canonical GM canola till date. The introduction of Roundup Gear up® canola has had a positive bear upon on farmers by controlling weeds that were erstwhile hard to mitigate. In 2014, GM canola planting area (hectares) was upwards to xiv% in 2014 from merely 4% in 2009 (Fig 3), representing a near 3-fold increase and contributing to Commonwealth of australia's growing biotech crop hectarage. This increment was more notable in WA, where GM canola was planted from 21% canola farmers in 2014, up from 0% in 2009. 22 This has led to more research and development of unlike canola varieties to ameliorate oil content and quality, yield and maturity. xx

PROBLEMS AND CONTROVERSIES

Although a successful technology, GM ingather use has been controversial and a hotbed for opposition. Their public image has been severely impacted leading to full or partial bans in 38 countries including the European Spousal relationship (Fig iv). This section highlights major controversies and reflects on some real problems faced by commercialised GM crops.

Figure 4. The figure depicts the current credence of GM crops in different countries. Green: National bans. Yellowish: Restrictive laws, Red: No formal laws (Source: 52 ).

Monarch Butterfly Controversy (1999)

The Monarch butterfly controversy relates Losey et al.'s publication in Nature wherein they compared Monarch butterfly (Danaus plexippus) larval feeding cycle of milkweed (Asclepias curassavica) dusted with N4640-Bt maize pollen to a control (milkweed dusted with untransformed corn pollen). They observed the N4640-Bt reared larvae to swallow bottom, grow slower and accept higher bloodshed and predicted N4640-Bt maize to have significant off target furnishings and significantly bear on Monarch populations due to the following reasons:

  • Monarch larvae's principal diet is derived from milkweed, which commonly occurs in and around the corn field edges.

  • Maize pollen shedding coincides with monarch larval feeding cycles during seasonal summer.

  • ∼50% of the Monarch population is full-bodied within the Us maize belt during summer, a region known for intense maize production. 23

Losey et al.'due south conclusions were challenged by academics for improper experimental blueprint and validity and soundness of extrapolating laboratory assays to field testing. There were many subsequent studies performed, depicting Bt-maize to exist highly unlikely to affect Monarch population. For instance: Pleasants et al., 24 reasoned that several factors, about notably rainfall (reducing pollen past 54–86%) and leaf pollen distribution (xxx–50% on upper found portions/preferred larval feeding sites) reduced larval exposure to Bt-maize pollen 24 and Sears et al., 25 argued that Bt-maize production, should it rise to ∼80% would only affect 0.05%-6% monarch population. 25

Nevertheless, Losey et al.'s results garnered acclaim in the press for raising both the public'due south and biotech companies' consciousness almost possible off-target Bt-maize on monarch butterflies. However further attempts to extrapolate their results to other Bt and GM crops have been unsuccessful, with current evidence suggesting effectiveness in insect control without off-target effects. 25

The Séralini Affair (2012)

The Séralini affair concerns itself with a controversial GM crop study past Gilles-Éric Séralini in Springer during 2012–14. The original paper published in 2012 studied the consequence of NK-603 Roundup Set up® Maize (NK-603 RR Maize) on rats. Information technology used the same experimental setup as an before Monsanto safety study to proceeds maize approval 26 and reached the post-obit observations:

  • Significant chronic kidney deficiencies representing 76% of contradistinct parameters.

  • 3–5x higher incidence of necrosis and liver congestions in treated males.

  • 2–iii-fold increase in female handling grouping bloodshed.

  • High tumour incidences in both treated sexes, starting 600 days before than control (only one tumour noted in control).

The 2012 written report attributed observations to EPSPS overexpression in NK-603 RR Maize, found the Monsanto written report conclusions "unjustifiable" and recommended thorough long-term toxicity feeding studies on edible GM crops. 27 The paper divided stance, with Séralini being framed as both as a hero of the anti-GM movement and as an unethical researcher. His paper drew heavy criticism for its flawed experimental pattern, animal blazon used for study, statistical analysis and data presentation deficiencies and overall misrepresentations of science and was retracted (Arjó et al., 2012,. 28 In 2014, Séralini republished his nearly-identical report in expanded form which since continues to fuel the GM crop debate.

GM Crops: An Imperfect Technology

Despite the higher up controversies being proven unfounded, GM crops are an "imperfect technology" with potential major health risks of toxicity, allergenicity and genetic hazards associated to them. These could be acquired by inserted cistron products and their potential pleiotropic furnishings, the GMO's natural gene disruption or a combination of both factors. 4 , two The nearly notable example of this is Starlink maize, a Cry9c-expressing cultivar conferring gluphosinate resistance. In the mid-1990s, the USDA'southward Scientific Advisory Panel (SAP) classified Cry9c Starlink as "potentially allergenic" due to its potential to interact with the human immune system. In 1998, the The states Environment Protection Bureau (EPA) granted approval for Starlink's use in commercial animal feed and industry (eg: biofuels) but banned it for homo consumption. Following this, relatively small Starlink quantities (∼0.5% of the U.s.a. corn acreage) were planted between 1998–2000. 29 , 30 In 2000, Starlink residues were detected in food supplies not simply in USA but also EU, Japan and South korea where it completely banned. Furthermore, the EPA received several adverse allergic effect reports related to corn, prompting a worldwide Starlink recall. Most 300 unlike maize products were recalled in US alone by Kellogg'due south and Mission Foods. Starlink inadvertently affected ∼l% of US maize supply and depressed The states corn prices by 8% for CY2001. 31

Another trouble faced past GM crops currently is pest resistance due to gene overexpression leading to pest evolution via natural selection. Indeed, an analysis of 77 studies' results by Tabashnik et al. depicted reduced Bt-crop efficacy caused by field evolved pest resistance for 5 out of thirteen (38.4%) major pest species examined in 2013, compared to just 1 in 2005, 32 Table ane). Furthermore, such resistance tin can be evolved over several generations in a relatively short time as nigh insects have shorter life spans. In maize, S.frugiperda and B.fusca resistance was reported after just 3 and viii years respectively, consistent with the worst instance scenarios. In the old, information technology led to crop withdrawal in Puerto Rico and was reported to still bear on maize growers in 2011, 4 years afterwards crop withdrawal. In India, P. gossypiella resistance currently affects ∼90% Bollgard-Two Bt-hybrid cotton growers and ∼35% (four million ha) of cultivable cotton fiber area in key regions. 32 , 33

To mitigate the problems regarding GM technologies, a series of strict regulatory measures have been proposed to prevent cross-contagion of dissever-approved GM crops banned for human consumption. These include implementation and enforcement buffer zones to preclude cross contagion of crops, improve laboratory testing to confirm adverse allergic issue cases and an overall inclusion of stakeholders and representatives in policymaking and communication. 30 Additionally, Bt pest resistance could be controlled by implementation of high-dose Bt toxin standards in transgenic crops and evaluation of insect responses, integration of Host plant resistance (HPR) traits in cultivars to control secondary pests, 34 training of abundant non-Bt plants refuges near Bt crops and proactive implementation of two-toxin Bt-pyramids producing ≥ 2 distinct toxins against as single pest species. 32 These suggested measures in pest management and regulation if implemented could aid the agriculture industry overcome the imperfect problems of GM crops while significantly regaining public trust of this applied science.

GM Agronomics: TRENDS AND Time to come AVENUES

The GM seed market has changed drastically since 1996 from a competitive sector endemic by family unit owners to one of the fastest growing global industries dominated by a modest number of corporations. Analysts predict a Compounded Annual Growth Charge per unit (CAGR) betwixt ix.83–10% between 2017–2022 for this industry where information technology is projected to reach US$113.28 bn, an approximately four-fold increase from Us$26.vii bn in 2007, 35 , 36 MarketWatch, 2016). This has been attributed to a rising biofuel adoption in lieu of conventional fuels in Asia-Pacific (APAC) and Africa, leading to increase plantings of energy crops (wheat, sugarcane, corn and soybean) for production. Still, despite growth spikes in APAC and Africa, North America currently dominates the GM seed industry with a market place share of ∼30%, and is forecast to do so in 2020 (MarketWatch, 2017).

The GM seed market has currently been consolidated past the "big five" companies: Monsanto, Bayer CropScience, Dupont, Syngenta and Groupe Limagrain (Table two). As of 2016, they account for 70% of the market (up from ∼threescore% in 2009). 37 , 38 The "big five" players are currently acquiring and forming joint ventures with smaller firms and competitors on a transnational calibration, serving as potent entry barriers in this manufacture. 36 Since 2016, major ongoing Mergers and Acquisitions (Grand&Every bit): Syngenta's takeover past ChemChina (completed June 2017- US$43 bn), 39 Bayer-Monsanto merger (ongoing- $66bn) forty and Dow-Dupont merger (∼US$140 bn- antitrust approval) 41 have been happening in the industry. Only time volition make up one's mind how these M&Every bit affect the industry, growers and consumers.

Tabular array 1. Crops reported with >50% pest resistance and reduced efficacy.

Table 2. A snapshot of the "big five" GM seed companies.

The latest reports indicate that the agriculture industry invests effectually $69 billion globally on its Inquiry and Development (R&D). 42 This investment has fuelled inquiry many emerging avenues for GM crop technology. However, innovation has strictly been influenced by the "big 5" due to broad patent claims, and high inquiry, legal and development costs for patent eligible products. For instance, the top three seed companies controlled 85% transgenic and seventy% non-transgenic corn patents in USA in 2009. 36

In the GM seed market, R&D is currently occurring in the conventional areas of insect resistance, increased crop yield and herbicide tolerance. Increasing R&D has too been invested on precision site-directed nuclease techniques (CRISPR, ZFNs and TALENs) for desired factor integration in host plants. xiv , 43 Current studies testify negligible/zero off target mutations (Schnell et al., 2015,. 44 This is starkly contrasting to conventional breeding techniques which are ofttimes associated with undesired alteration risks via linkage drag and random, unspecified mutations. 45 Additionally, biofortification and stress tolerance have been identified every bit areas for future GM seed research. Both fields are currently of major interest with a growing body of scientific studies. They tackle fundamental problems: while biofortification addresses malnutrition and micronutrient deficiency; stress tolerance addresses biodegradation, climatic change and shrinking cultivable area. Since the development of Vitamin-A biofortified rice in 2000, 46 studies highlight further extrapolation in enhancing human diet using biofortifications, with recorded success in iron and zinc. 47 Moreover, recent genetic modification studies in Arabidopsis and Barley have depicted adaptation to stress tolerance and biomass growth in adverse atmospheric condition (Mendiondo et al., 2016,. 48 Iii stress-tolerant corn hybrids [Pioneer Optimum AQUAmax™ (Dupont Pioneer), Syngenta Artesian™ (Syngenta) and Genuity™ DroughtGard™ (Monsanto)] are currently being marketed for drought resistance, 49 showcasing enormous potential for economic profitability in the above areas.

Determination

GM crops tin can mitigate several electric current challenges in commercial agriculture. Current market trends project them equally 1 of the fastest growing and innovative global industries, which not simply benefit growers but also consumers and major country economies. Even so, it is imperative that the agricultural industry and scientific discipline community invest in better science communication and regulation to tackle unethical research and misinformation. Imperfections and major GM applied science tin also be combated by stricter regulation, monitoring and implementation by regime agriculture bodies, a globally improved risk mitigation strategy and advice with growers, therefore ensuring greater acceptance. With key innovation in precision gene-integration technologies and emerging research in biofortification and stress tolerance, GM crops are forecast to bring productivity and profitability in commercial agronomics for smoother progress in the hereafter.

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Source: https://www.tandfonline.com/doi/full/10.1080/21645698.2017.1413522

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