What really is in the pipeline from GM crops?

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23 Οκτ 2013 (πριν από 3 χρόνια και 5 μήνες)

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What really is in the pipeline
from GM crops?

Dr Janet Cotter

Greenpeace International Science Unit

University of Exeter

UK

The current situation

Concerns of GM crop cultivation


deliberate
release of GMOs to the environment
(i.e. not contained use in lab).



related to the trait (e.g. effect of insect resistant
GM crops on non
-
target organisms).



related to the genetic insertion



outside the complex
regulatory network that controls
gene expression .



can interfere with normal plant function.

What we hear…

1)
GE crops are widely grown

2) GE crops can contribute to food security (in the
future) because they can deliver crops with…


Increased yield


Drought tolerance


Nitrogen
-
fixing cereals


Enhanced micronutrients (e.g. Golden Rice)

The Reality…

From:
Quist et al.
2013. Hungry for Innovation: pathways from GM crops to
agroecology
.
In
: European Environmental
Agency (EEA) Late lessons from early warnings: science, precaution, innovation
. Ch. 19. www.eea.europa.eu

GM crops are grown
on
only 3
% of
agricultural land
globally.


Virtually
all these GM
crops are either
herbicide
-
tolerant,
insect resistant or
both.


No GM crops for increased yields.


No
evidence that
current GM crops increase
food
security



designed for large scale commodity
growers.


GM
crops
are patented.


Farmers face issues of contamination and liability.

(see, e.g. IAASTD 2008,
www.assessment.org
, Quist et
al.
2013 op cit.)

GM crops do not currently contribute
to food security.

Simple and
Complex Genetic
Engineering

Current commercial GM crops


simple traits

Current commercial GM crops contain relatively
simple constructs that produce a non
-
metabolomic

protein. E.g.



Herbicide tolerance


production of protein conferring
tolerance to a particular herbicide



Insect resistance


production of protein toxic to a
specific pest.

Even for these relatively simple constructs,
questions surround effects, safety is questioned.

Typical insert for a simple GM trait





Genetic insert for Roundup Ready Soya


Complex traits


Main focus of crop development is traits to cope
with climate change (e.g. drought tolerance) or
increased nutrition (e.g. enhanced vitamins).



Most of these desirable traits are controlled by
multiple genes.



I.e. they are “complex” traits.

GM crops for complex traits

At the R&D stage


not in commercial farming



Most of the “hopeful” traits, e.g. nitrogen fixation,
increased yield.


Nature of the genetic engineering is complex.


Often require several genes, including regulatory
sequences (e.g. ‘Golden’ Rice).


OR over
-
expression of one inserted gene (e.g.
Monsanto’s drought tolerance maize).




E
xample of complex genetic
engineering




G
enetic insert for
‘Golden’ rice


Problems with
g
enetic engineering
for complex traits



Plant chemistry is complex.



Metabolic pathways are not completely known or
understood.



High potential for unexpected and unpredictable
effects with complex genetic engineering.



May have human health implications, e.g. if a toxic
product resulted from an unexpected pathway.



May have environmental implications, e.g. if an
unexpected product was toxic to wild animal species.

Genetic engineering for complex
traits is very difficult


Technically very difficult


Assessment for food, feed and environmental
safety very difficult.


Genetic engineering is not suited to complex
traits.


Stuck in the pipeline?




Tolerance to new herbicides, e.g. 2,4
-
D,
dicamba
.


Stacked traits


herbicide tolerance with insect resistance


multiple insect resistance


multiple herbicide tolerance?


Herbicide tolerance and insect resistance
in new crops, e.g. eggplant
.


What’s really in the pipeline for GM
crops?

New ways of inserting genetic material into
plants.


Some have more precise placement


Some use genes from the same species
(
cisgenesis
)


Some don’t produce a new protein, but maybe
other risks (e.g. uptake of small RNAs affecting
gene expression in humans


new science)

But it’s the insertion of genetic material that gives
rise to the concerns.

New genetic engineering technologies


Science progresses:


“Junk” DNA is no longer junk, but important in
regulation


Complexity of genetic regulation being
realised.


New theories on activation of duplicate genes
in response to stress.


Makes genetic engineering look very
crude.

Better understanding of genome
function, more concern over GM
crops

Non genetic engineering plant
breeding

Biotechnology is not Genetic
Engineering


Often “biotechnology” is taken to be
equivalent to “genetic engineering”



But biotechnology is far broader.



Biotechnologies
encompass a wide array of
plant breeding technologies, of which only
one is genetic engineering.

The contribution of Marker Assisted
Selection (MAS)


Marker Assisted Selection (MAS) or “smart
breeding”.


Allows the identification of “markers”


segments of DNA located near the gene of
interest.


The presence of this marker in offspring
indicates that the desired gene is present.


It is “smart” conventional breeding


not
genetic engineering.

1)
Drought tolerant maize in Africa

In the past 5 years, 34 drought tolerant varieties (hybrid
and open
-
pollinated) have been released in 13 sub
-
Saharan African countries and are used by an estimated
2 million smallholder
farmers.
http://dtma.cimmyt.org/


2) Drought tolerant rice in Asia

IRRI has developed drought
-
tolerant varieties which have
been released in several
countries including India,
Philippines and Nepal
.
http://irri.org/






Examples


Drought tolerant wheat from CSIRO (Aus.)


Submergence tolerant rice (IRRI).


Bacterial blight resistant rice in Philippines,
India and China.


Nutrient enhanced crops: pro
-
vitamin A sweet
potato and maize; iron and zinc rich bean and
rice (
Harvestplus

and others).

Yet more examples…

Further details of
MAS in Greenpeace
reports and
technical briefings

www.greenpeace.org

MAS
harness

crop diversity

MAS has come of age


The bottleneck to MAS is identification of
markers, which is facilitated by sequencing of
the genome.


Several crop genomes have been made
publically available in the last few years:


rice (2002), maize (2009), sorghum (2009), soy
(2010), potato (2011), pigeon pea (2011), tomato
(2012), chickpea (2013).

Conclusions


GM crops are almost entirely herbicide tolerant or
insect resistant


not likely to change in the future.


Genetic engineering is not suited to complex traits


not appropriate technology for desired traits.


Other modern breeding methods, such as Marker
Assisted Selection (MAS) are producing varieties with
desired traits


especially public funded efforts.



BUT… it’s not only about crop varieties, it’s about
how we farm.