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Current Status of GE crops worldwidea. What crops have been commercialized?

b. What are the potential and current positive and negative impacts (benefits/risks)

Cholani WeebaddeMichigan State University

Global food production – facing challenges

• Challenge: By 2050 we need to double food production to feed the projected 9.2 billion people using less resources (fossil fuel, water & nitrogen) (7.6 billion people today; just 17 years after 6 billion)

• How: Need to increase crop productivity by integrating best of conventional crop technology & best practices of crop biotechnology applications including novel traits

High productivity paths to Agriculture

• Green revolution vs. “Industrial” farming– Traditional farming – Pre 1980s (where we were)

• Excessive use of water, fertilizer, pesticides, diesel fuel and excessive tilling of soil

– Precision farming – Post 1980s (where we are…)

• New irrigation technologies, more precise use of fertilizer, controlled use of pesticides, reduced tillage to save diesel fuel

• Biotech/GE crops fit into Precision farming: Seeds with novel traits to make crops better adapted to biotic and abiotic stresses

Bt Corn protects against corn borer damageSource: Robert Paarlberg

How is a GE/GMO crop different from Traditional and Marker Assisted Breeding?

Source: ISAAA 2016

….the “big four” GE crops adopted

For GE crops adoption rates in specific countries, please refer to ISAAA Brief 52: https://www.isaaa.org/resources/publications/briefs/52/download/isaaa-brief-52-2016.pdf

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A steady increaseSource: Crop BioetchUpdate, July 27, 2016

Why farmers like GE crops - USA

• Protect against crop losses from diseases and weeds

• Higher returns per hectare

• Reduced pesticide use and costs

• Ease of production with large farms (less time spent on the tractor spraying pesticides or cultivating fields)

If you consider insect and herbicide tolerant crops;

GE crops commercialized in the US

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1996

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Alf

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(201

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2016

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Source: https://gmoanswers.com/current-gmo-crops

All GMO crops in the US market have gone through the regulatory application and approval process…

Source: https://gmoanswers.com/current-gmo-crops

Traits of GE crops commercialized in the US

Traits – Insect resistance (Bt), Herbicide tolerance (eg. RR), Resistance to viruses, Resistance to fungi, Drought tolerance, Non-browning

The science behindBt Insect Resistant

Biotech Crops

Why did scientists develop Bt crops?

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• Bt – Bacillus thuringiensis

• Common soil bacterium

• Produces crystal (Cry) proteins during sporulation

• Different strains of Bt produce different Cry proteins that are toxic to a variety of insects

• Led to development of Bt insecticides against insect pests

Bt insecticides generally contain a mixture of several proteinsExample: Dipel = Bt kurstaki (Btk)Cry1Aa, Cry1Ab, Cry1Ac, Cry 2Aa, + Cry2Ab

Bt and its importance for Agriculture

Activation of toxin:- crystals solubilizedunder high pH

- protein cleavedby gut proteases

Ingestion ofspores,crystal

proteins(= protoxins)

Toxin binding to gut receptors:- paralyzes gut- insects stops feeding- gut membrane leaks- bacteria multiply in body- septicemia

Slide of Chris DiFonzo

How Bt acts as an insecticide

Mammalian Toxicity, rats

cyhalothrin 79-144 mg/kg

carbosulphan 90-250 mg/kg

cypermethrin 250-2000 mg/kg

Bt kurstaki > 5,000-24,000 mg/kg

-Human gut has low pH

-Humans don’t have the gut receptors

When comparing Bt to other insecticides,

Bt is sometimes referred to as

“practically non-toxic” –Why?

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Source: Chris DiFonzo

Why Bt is “practically non toxic” to humans

Bt is a common insecticidal spray used in organic agriculture, on sensitive habitats, and home gardens

But, it has limitations…..

Insect larvae are the most susceptible to Bt

1. Timing is crucial (have to spray at larval stage and spores must be eaten by larvae)

2. Need to scout large fields to time applications right

3. Bt gets exposed to UV and breaks down fast(within hours) – have to apply again repeatedly

• Spraying large fields

requires hiring of

equipment (coverage)

• Repeated applications

add cost

• Spraying Bt on large

farms is not cost effective

compared to pesticides

Bt sprays are not economical for large fields in the US

Bt Crops developed to address

limitations of Bt insecticides

– Coverage – 100% since all plant parts make

the insecticide

– Timing – Insecticide is made all the time

– Breakdown – Insecticide is within the plant

in high dose (not exposed to UV)

– Cost – Is part of the cost of seed (no

additional costs required for application)

Why farmers like Bt crops

Benefit: Less damage from

European corn borer. Less

pesticides needed for control

Added benefit: Insect damage

attracts secondary infections

with fungi that produce

mycotoxins toxic to humans

Why farmers like Bt crops

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Yieldgard RW- trace feeding

Untreated Corn- severe feeding- lodging, goosenecking

Soil insecticide Herculex RWUntreated

Makes machine harvesting difficult!! – yield loss

Soil insecticides used:Broad spectrum, difficult to apply, depends on soil moisture

Bt corn seed – no calibration, handling of pesticide, targeted for the pest

Why farmers like Bt crops Bt crops have reduced the amount of insecticides used in the fields…

- An issue that comes after the general release of a Bt crop. Therefore, we can only take measures to delay the occurrence of resistant pests

These issues are not new or unique to GE crops. Many insects and weeds have evolved resistance to pesticides in the past requiring more toxic pesticides for their control

However, high selection pressure increases chance of pests developing resistance to GE crops….

https://www.nature.com/news/crispr-microbes-and-more-are-joining-the-war-against-crop-killers-1.21633

In fact, field resistance to Bt sprays were observed before GE crops were commercialized….

We can expect the same to happen with Bt transgenic crops in the field….

First reports of high resistance to Bt sprays in the field was found in Hawaii, Florida and New York in the US; and in Malaysia in 1990, 30 years after commercial use of Bt sprays (and six years before Bt crops were first commercialized)

Laboratory experiments to test development of pest resistance against Bt…

• Thirteen different insect colonies developed resistance when exposed to Bt in the lab including:

• European corn borer, tobacco budworm, pink bollworm moth, Egyptian cotton leafworm, cottonwood leaf beetle, beet armyworm etc.

Scientists expected the same could happen with Bt crops in the field if not managed properly….

Source: Nappl, 2000

Strategies were put in place for delaying resistance from occurring….

• Use of a high dose strategy where both susceptible (rr) and partially resistant (Rr) types are killed

• Use of Refuge area to maintain a susceptible (rr) population so that through mating with RR, only Rrtypes are produced (and killed from high dose)

• Pyramiding multiple resistance genes (stacked genes)

• Use of cultural practices

However, 5 insect pests developed resistance to Bt crops…

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CONCLUSION: “Although regulations in the United States and else- where mandate refuges of non-Bt host plants for some Btcrops, farmer compliance is not uniformly high and the required refuge percentages may not always be large enough to achieve the desired delays in evolution of resistance. Both in theory and practice, using Bt crops in combination with other tactics as part of integrated pest management may be especially effective for delaying pest resistance

Reduction in the use of insecticides in the US upon adopting Bt corn and cotton crops

Source: Jorge Fernandez-Cornejo, Seth J. Wechsler, and Michael Livingston, 2014

“Pounds of insecticide (per planted acre) applied to corn and cotton crops have decreased steadily over the last 10 years (except for cotton in 1999-2001, when application levels were distorted during the boll weevil eradication program)”

However, complete control of the primary pests allow secondary pests to become more prominent

Therefore, strategies need to be put in place to control secondary pests…

Percent reduction of pesticide use in Bt Cotton compared to conventional (adapted from Fitt et al. 2004)

Sanvido et.al, Oct 2006

BollgardII – (Cry1Ac/Cry2Ab2) - 92% reduction

Additional resistance to secondary pests of cotton

• Cotton – highly susceptible to several serious insect pests (primary & secondary);– budworm-bollworm complex with considerable damage

• Control of secondary pest may require different genesBollguardII has Cry1Ac/Cry2Ab2

• Second gene is affective against secondary pests (soybean and cabbage looper, saltmarsh caterpillar, beet and fall armyworm)– One gene: 43% reduction– Two genes: 92% reduction

Use of an additional gene allows control of the secondary pests in cotton…

Will need to be a continuous effort….

The science behindRound-up Ready/Glyphosate

Herbicide Tolerant Biotech Crops

Why did scientists develop RR crops?

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Glyphosate mode of action

Source: Jim Kells

Shikimate

PEP

EPSP

TyrosineTryptophanPhenylalanine

Glyphosate

EPSP Synthase

Glyphosate (herbicide) blocks action of EPSP Synthase – 3 essential amino acids not made

Mode of action: Glyphosate tolerant crops

Source: Jim Kells

Shikimate

PEP

EPSP

TyrosineTryptophanPhenylalanine

Glyphosate

EPSP Synthase

Insert an EPSP Synthase with an altered binding site

Why farmers like Round-up Ready crops?

• Weeds are a major production constraint for crops

• A vast amount of toxic herbicides are used for weed control

• Once herbicides are sprayed, need to wait for herbicide to degrade before planting the crop to avoid damage

Weed control with

Glyphosate

Weeds not controlled

HT crops – impact on tillage practices

• Use of Round Up Ready crops was correlated with increase in reduced tillage or no-till practices

• Environmental considerations: tillage exposes soil to wind and water erosion which can carry both soil and agricultural chemicals

• Reduced tillage can – reduce erosion, groundwater contamination, and

conserve nutrients and organic matter– increase soil insect and microbial populations– reduce soil compaction resulting from passages across

the field

- indirect (unexpected) advantage

Recent data on tillage practices…

Source: Jorge Fernandez-Cornejo, Seth J. Wechsler, and Michael Livingston, 2014

However, high selection pressure increases chance of weeds developing resistance to HT crops….

Other more toxic herbicides are being reduced – that’s good

Use of Glyphosate has increased –selection pressure is very high

https://www.nap.edu/read/12804/chapter/2#3SOURCE: USDA-NASS, 2001, 2003, 2005, 2007, 2009a, 2009b; Fernandez-Cornejo et al., 2009.

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However, with increased selection pressure, weeds develop resistance to Glyphosate

Source: Chemical & Engineering news, 2015

Weeds resistant to Glyphosate in the US

Development of resistance to herbicides is not new to GE crops

Source: Ian Heap, Herbicide resistant weeds, 2014

Responsible use of technology is

important!

Genetic engineering can be used to make GE crops with stacked traits too!

We can also insert both Bt and RR ready genes in to a plant to

make it resistant to insects as well as be tolerant to herbicides!

Remove all genes needed to make a crown gall – “don’t make a crown gall”

Cry3Bb1

Cry 1F

Roundup Ready

Stacking genes allows you to develop one GMO with multiple traits such as a) Herbicide toleranceb) Resistance to corn borerc) Resistance to corn

rootworm

Stacked traits are gaining more popularity compared to single traits…

Example: SMARTSTAX (with 8 genes!)

• U.S./Canadian approval, 20 July 2009

Dow AgroSciMonsanto

Herbicide Tolerance Liberty LinkRoundup Ready

CornBorer

Rootworm

Cry 1FCry 1A.105Cry 2Ab2

Cry 34 Ab1Cry 35 Ab1Cry3Bb1

Source: Chris DiFonzo

You can also pyramid more resistance genes for the same pest in a stack

Cry 1A.105

Cry 2Ab2

Cry 1F

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Economic benefits from growing GE crops from 1996 – 2014 and 1996 - 2015

Cost of production reduced due to less ploughing, use of fewer pesticides and less labor involved

Environmental benefits of GE crops

The science behind

Virus resistant GE Crops

Why did scientists develop virus resistant crops?

Why was virus resistant Papaya developed?Threat from Papaya Ring Spot Virus

(PRSV) in Hawaii

1940 – PRSV discovered

1950s –

1. Eliminated large productions from Oahu Island

2. Papaya Industry relocated to Puna District

(free of PRSV)

1980s –

1. 95% production established in Puna

2. Research started on resistance through transgenic approach

1992 – PRSV spread to the Papaya fields in Puna

Small scale field trial with the transgenic lines

1998 –GM papaya commercialized

GM Papaya saves the industry!

Transformed papaya cell – expresses modified viral gene – allows the plant to recognize the virus when it enters

The virus is targeted for degradation, cannot multiplyResistant

Non-transformed papaya cell

Virus multiplies in plant cells and spreads through plant

Susceptible

The science behind

GE Crops with the Non-Browning trait

Why did scientists develop non-browning crops?

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Polyphenol oxidase which causes browning

For more information: https://nas-sites.org/ge-crops/category/pastevents/webinars/

Benefit to consumers – Reduce food waste

For more information: https://nas-sites.org/ge-crops/category/pastevents/webinars/

For more information: https://nas-sites.org/ge-crops/category/pastevents/webinars/

The science behind

Late Blight resistant potato

Why did scientists develop late blight resistant potatoes?

Cultivated and wild potatoes (photo: Peggy Greb)

Potato late blight resistant genes were found in wild potato species – But it is so hard to transfer to cultivated background!

- Crossing wild & cultivated potato gives sterile triploid (3X) potatoes

- Colchicine chemical is used to double chromosome number to get a fertile hexaploid (6X)

- Hexaploid when crossed to diploid wild potato gives tetraploid (4X) progeny

Cultivated (4X) Tetraploid

Wild (2X) Diploid

At every stage embryo rescue may be needed to go to the next step. Even so, you never know if the resistance gene from the wild potato ever got transferred to the cultivated (4X) after all that effort!

It is much more straightforward & efficient (less errors) to clone resistance genes from wild potato & genetically engineer it to the cultivated potato Cultivated and wild potatoes (photo: Peggy Greb)

Potato late blight resistant genes were found in wild potato species – But it is so hard to transfer to cultivated background!

So, the genes were isolated and cloned so they could be inserted into cultivated potato using Genetic Engineering techniques – to develop resistant varieties faster

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Plant Transformation Process – enabled the development of late blight resistant potatoes faster…

The late blight resistant varieties developed perform as expected in the laboratory, greenhouse and the field….

IF genetic engineering was not possible for potato, how can you breed for resistance to late blight?

Because potato is polyploid species, genetics is complicated and breeding varieties conventionally takes many many years! https://gmoanswers.com/infographic-how-does-gmo-get-market-gmo-regulation-review-and-research-process

What it takes to get a GMO to the market…

How many countries are there in the world? 195

Regulations ask: Are GMO crops and products safe for food, feed and the environment?

- Every country has Biosafety regulations to ensure the safety of biotech products for the environment, human and animal health and biodiversity

- US has a coordinated approach and uses the principle of substantial equivalence

Principle: If a transgenic food or organism can be shown to be substantially equivalent in composition to that of a conventional organism of the same kind, the modified organism and its products should be judged to be as safe for consumption as the conventional ones

When genes come from different sources, there are concerns

Laboratory Biosafety

Greenhouse Biosafety

Confined Field Trials

Application for

Release

General Release

Food imports

Institutional Biosafety Committees (IBCs)

National Biosafety Committees (NBCs)

Plant Quarantine Officers (PQs)

Without proper regulatory systems in place, GE research

cannot move beyond the laboratory and greenhouse

biosafety stages

Biosafety regulatory application process

- Each country has their own regulatory system to evaluate

safety of GE crops and products at every stage from

development to deployment

- 3 committees look into safety; IBCs, NBCs and PQs

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US Regulation of Biotech products uses a Coordinated framework (1986)

Environmental Protection

Agency (EPA)

Food and Drugs Administration

(FDA)

US Department of Agriculture

(USDA)

*This is an over-simplified version so that it is easy to understand

Animal Plant Health Inspection Service (USDA-APHIS)Safety assessment for cultivation, movement and/or importation

Office of Pesticide Programs for safety assessment of pesticides (including distribution and labels)

Center for food safety and applied nutrition for food safety and labeling

Each agency in the coordinated framework use laws already in place to regulate GE organisms and their products

• US Government Role: Ensure that Biotech products are safe for consumption and environmental release

• Government regulation aims for:

– Transparency (rulemaking process)

– Predictability

– Science-based process

– Risk-based approach

US Coordinated framework (1986)

What is a Risk-based approach?

• Fundamental premises on risk:

– Omnipresent (risk is everywhere)– Identifiable– Measurable (Risk = Hazard x Exposure)– Manageable– Proper management Safety

• Other points:– Accommodation (can GE crops co-exist with non GE

crops?)– Self regulation

Potential issues faced with GE crops are carefully assessed by regulatory agenciesEnvironmental Biosafety

Weediness/InvasivenessPollen/Gene flowEffect of novel toxins on non-target organismsDevelopment of pest resistanceOther agroecological and crop management issues (eg. secondary pest issues and mixed cropping)

Food SafetyWhether the food derived from transgenic crops is safe for humans and animals

Socioeconomic & Ethical

You will hear about these tomorrow…

An example of how Biotech products get regulated with the Coordinated framework (1986)

Non browning Arctic Apple

Bt maize resistant to insect pests

Virus resistant papaya

USDA-APHIS

US EPA US FDA

No pesticidal properties so, US EPA has no role in the regulation

USDA, EPA and FDA

Both Bt corn and virus resistant papaya have pesticidal properties so, all three agencies regulate the crop and product

For more information: http://www.farmindustrynews.com/seed/refresher-how-gmo-crops-get-approved

GMO labeling in the US

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“On July 29, 2016, President Barack Obama signed a bill into law requiring the labeling of food containing genetically modified ingredients, following a drawn-out battle between the food industry and pro-labeling groups on the issue”

For Michigan: http://michfb.wsoldev.com/MI/GMOLabeling/

Why would we want to have GE crops anyways?

• Climate change is going to adversely affect agriculture and human well-being especially in the developing world by:– Yield declines in most important crops – South Asia predicted

to be most hardly hit– Increasing prices for most important agricultural crops and

products

• Agricultural sector needs to have tools for speeding up the development of new and improved crops to deal with constraints related to climate change

• Genetic engineering is one such biotechnology tool available for the plant breeder to improve crops

Risk of banning GMOs… A 2016 study

• Goal: Contribute to the literature on the benefits of GMO technology by estimating the impacts on price, supply and welfare

• Food price impacts range from an increase of 0.27% to 2.2%, depending on the region.

• Total welfare losses associated with loss of GMO technology total up to $9.75 billion.

• Substantial increase in GHG emissions predicted if GMO technology is banned (By modeling land use change owing to the loss of GMO traits)

Even after 20 years of eating GMOs, still there are a lot of misconceptions.

Interesting video on Simplot potato from The Daily Show:

https://www.youtube.com/watch?v=zY-UPHLJ31A (6.17 mins)

Did you learn anything new about GMOs today? What was it?

Questions?