What are Genetically Modified

Crops and how are they made?

Professor Idah Sithole-Niang

Department of Biochemistry, UZ

GMASSURE - UZ

Outline

• Definitions

• Concept of Genetic Modification

• Agricultural context

• Why biotech?

• Challenges/Opportunities

• Status & specific opportunities in Africa

• Non-GM products

Definitions

• Biotechnology is the use of biological

systems to create goods and services

• Gene manipulation

• Genetic engineering

• Genetic modification

• Transgenesis

– LMOs: living modified organisms

– GMOs: genetically modified organisms

Concept of Genetic Modification

through plant transformation

Identify genes of interest for a trait (eg. insect

resistant genes)

Insert into an organism of interest (eg. Insert

insect resistance gene into a susceptible plant to

make it resistant) – very common with crop plants

Genes can come from a variety of sources:

From the same plant species

From wild relatives

From another crop

From bacteria or another organism

Agricultural context

Cross breeding and induced mutation are important tools of plant breeding, they also have limitations:

1. Cross breeding only works between related plants.

2. For some species cross breeding is extremely difficult.

3. Cross breeding can take very long.

4. ‘Linkage drag”

5. Mutation is very undirected and unpredictable, HORIZONS sprl

Genetic Modification of Plants

Traditional

plant breeding x

“elite”

variety

Related

variety

Genetic

Modification

any

gene

source

HORIZONS sprl

Genetic Modification of Plants

Technical advantages:

• Specific

• Faster

• Possible with plants that do not

cross sexually

• Much greater reservoir of genes

HORIZONS sprl

Generating Varieties of Agricultural

Plants and Animals • Conventional breeding

– Crossing of two varieties with useful characteristics

– Hybrids

– Tissue culture

– Cloning

– Chemical mutagenesis

– Irradiation

– In vitro fertilization

– Artificial insemination

Using Radiation to Create Mutant Varieties of

Plants

Gamma Rays X Rays

Genes carry the information that is

passed from generation to

generation. They are the blueprint

of life

Anything that is alive has genes.

The information of genes is carried

in the form of DNA molecules.

The ‘language’ of DNA, is the same

regardless of the organism – A key

point for genetic engineering

DNA molecule

Breeders, geneticists, and genetic

engineers work with genes

Genes carry the

information that is

passed from generation

to generation. They are

the blueprint of life

DNA molecule

Breeders, geneticists, and genetic

engineers work with genes

Anything that is alive has

genes.

The information of genes

is carried in the form of

DNA molecules.

DNA molecule

Breeders, geneticists, and genetic

engineers work with genes

The ‘language’ of DNA

is spelt out in a simple

alphabet of 4 letters

A, C, G, T

DNA molecule

Breeders, geneticists, and genetic

engineers work with genes

The ‘language’ of DNA,

is the same regardless

of the organism – A key

point for genetic

engineering

DNA molecule

Breeders, geneticists, and genetic

engineers work with genes

Sigma ad 8/2008

How much of your

DNA sequence do

you share with a

banana?

A: None

B: 1%

C: 10%

D: 50%

E: 90%

Good grief!: I’m a banana!

You and Your DNA

Do you know that humans

share about 50% of their DNA

with a banana!

Getting genes into cells – plant transformation

2. Put the

engineered gene

into cells of the

desired plant

Step X step

Dr. Mufandaedza

Regulation of GM crops moves

through different stages of crop

development and deployment

Lab

Growth

Chamber or

greenhouse

Confined Field

Trials

General

release

Full safety

assessment

CFT Application General Release

Application

Approval

1. Why biotechnology?

• World population will reach 9 billion by 2040

• Some undernourished either in terms of both

quantity or quality

• Arable land shrinking due to erosion, pollution,

and other forms of land use

• Increasing shortage of fresh water for drinking

and irrigation

• Climate change will increase the need for

keeping up with well adapted crops

2. Why biotechnology ?

• Increasing demand for fuels and

chemicals from renewable sources as oil

reserves become depleted and oil-based

commodities more expensive

• 80% of world caloric intake comes from

only 4 crops

• Not a silver bullet but can contribute

significantly to finding solutions to these

challenges

1.Challenges

• Need to produce:

–More crops per hectare

–More crop per liter of water

–Marginal-

–Arid- or Saline land

2. Challenges

Enhance:

• Nutritional value of crops

• Crop diversity

Reduce:

• Dependency on pesticides & fertilizers

• Post-harvest losses during storage &

transport

• Soil erosion

Do these challenges apply to

Zimbabwe?

What are the Opportunities'?

1. Opportunities/pipeline

Biotic stress: Disease resistance

• Fungal resistance – Banana/Black

sigatoka

• Virus resistance – banana, cassava, yam,

papaya, groundnut, sweetpotato & tomato

• Bacterial resistance – rice, cassava,

banana & potato

• Pest resistance/field & storage

2. Opportunities/pipeline

Abiotic stress tolerance

• Drought tolerance –maize (WEMA),

wheat rice sorghum etc

• Salinity tolerance- maize, wheat,

tobacco, sorghum, rice etc (NUWEST)

3. Opportunities/pipeline

Enhanced nutrition: rice, cassava &

sorghum –(pro-vitamin A, Fe, Zn, Vit E)

• Banana- pro-vitamin A & Fe, wheat- Fe

• Maize, potatoes, sorghum & cassava

(protein quality). Mustard pro-vitamin A

• Others: reducing cyanogenic compounds

in cassava & changing available P by

reducing phytates

You mean there are all these

wonderful Opportunities!!!!??

Why the controversy?

What are the issues??

Mr Dhlamini

Any Good examples in the

BRICS?

BRAZIL, CHINA & INDIA

Prof CJC

What would it feel like if the

DR & SS had $1 billion budget?

What would it feel like if the NBA reviewed, 14

applications annually???

Whos Who In Africa?

and where are they with their

regulation?

Dr. Mufandaedza

Developing high quality

Pod-borer-resistant cowpea varieties Problem

• Insect damage in the field and in

storage

• Losses can be up to 80%.

• Frequent insecticide sprays

required

• Host plant resistance is a low-cost

and environmentally friendly control

measure for the farmer

Product

High yielding cowpea varieties with

increased resistance to insect pests -

Bt-Cowpea

(Pod borer- Resistant Cowpea) Figure 7. Pod damage by M. vitrata

Resistance to Banana Bacterial Wilt

for East African Highland Bananas

Constraint:

Banana bacterial wilt (BBW) disease caused by the bacterium

Xanthomonas campestris pv. musacearum (Xcm)

• Africa drought-prone

• Maize is the most widely grown staple crop in Africa – affected by drought

• In 2003 WFP spent $0.57b on food emergency due to drought in Africa

Recorded droughts between 1971 and 2000, and the number of people affected

Water Efficient Maize for Africa

(WEMA)

Drought tolerant Maize

Is there a drought in

Zimbabwe??

Do some of these solutions

apply??

Gene silencing line (with

gene to control CMD)

Susceptible

(without the

gene)

Confined Field Trial to Evaluate Transgenic Cassava for Resistance to Cassava Mosaic Disease

- D3/2/NBC/4/08

Symptomless leaves and stems of best test line (1-718-001)

Severe streaking and dieback on control line without gene

Symptoms of CBSD at Harvest: CBSD Study

What will you have for dinner???

Best test line; No rotting of

the storage roots Control line without the

gene; severe rotting of roots

Symptoms of CBSD at Harvest: CBSD study

Eggplant (Brinjal or Talong)

Fruit and Shoot Borer

This damage is prevented by Bt.

Bt cotton CFT in Malawi 2013

Mr. Mhandu

Biotech crops on trial in Africa • RSA: potatoes, sugarcane, maize

• WEMA : RSA, Kenya, Uganda

• Kenya: cotton, maize, SP, cassava

• Egypt: cotton, potato, wheat, cucumber, melon

• Uganda: banana, cotton ,cassava ,maize, rice

• Nigeria - cowpea, cassava, sorghum

• Burkina Faso: cowpea, rice

• Malawi – cotton, cowpea , banana

New Breeding Technologies

Non- GM Technologies

Need we even dream???

Non-GM: Genome editing

technologies • CRISPRs: clustered regularly interspaced

short palindromic repeats

• ZFNs: Zinc finger nucleases

• TALENs : transcription activator-like

effector nucleases

Zinc Finger Nucleases

• Successfully used to introduce herbicide

tolerance = WEED CONTROL

TALENs

• Used to delete and cut out a gene in rice

that confers susceptibility to bacterial

blight disease

CRISPRs

• Chinese Academy of the Sciences

developed a powdery mildew-resistant

wheat through advanced gene editing

• Example of modification of a food crop

without using insertion foreign genes

Three Requirements for growth

of GM crops in Africa

• Political will and support from lead

countries, governments and institutions

• Establishment of responsible and

efficient regulatory systems, that are

appropriate for Africa given the limited

resources

• Communication with Society

transparently and accurately

Thank you for your attention

Acknowledgments

• Clive James, ISAAA

• Cholani Weebadde, Michigan State

University

• Peter Davies, Cornell University

• Program for Biosafety Systems

• African Biosafety Network of Expertise

• GMASSURE

• African Agricultural Technology Foundation

Current Status of Genetically

Engineered Crops • Grown in over 28 countries around the world by over

18 million farmers – 420 million acres in 2013

• Largest in acreage – US (171 million acres)

• Largest in terms of farmers – India and China – 14 million farmers

• Types of products – maize, soybeans, cotton, canola, sugar beets, alfalfa, squash, papaya

• Types of traits – built in pesticides, resistant to herbicide, resistant to virus

• For the first time in 2012, developing countries grew

more, 52%, of global biotech crops in 2012 than

industrial countries at 48%

Drought and African Agriculture

• The WFP spent $0.565B of food emergency to respond to drought in sub-Saharan Africa (SSA) in 2003

• Over 95% of cropland in SSA is rain-fed and will remain so in the near future

• The risk of drought prevents investment in improved agricultural products

Yield stability is key to unlock the value of basic inputs

Recorded droughts between 1971 and 2000, and the number of people affected

(Slide source: Dave Songstad, Monsato)