1. SPPS Newsletter - March 2015 - Rewilding
The term rewilding is well known in conservation biology for restoring degraded
habitats but very recently it got a new meaning in plant breeding. And consumers
might soon have to deal with it in the supermarket's fruit and vegetable
department. The new meaning was coined by Michael Palmgren and colleagues
at the University of Copenhagen in a cross-disciplinary study that appeared in
print in the Cell Press journal Trends in Plant Science in March 2015. Here,
the authors - a team of plant biologists, ethicists, philosophers, economists and
lawyers - suggest that instead of introducing new properties into our crops, we
should focus on reestablishing useful properties that their ancestors once
possessed but was gradually lost during the 10,000 years mankind has practiced
plant breeding.
Such lost properties are e.g. tolerance to biotic stress (pests, pathogens,
herbivores and diseases) and abiotic stress (drought, flooding, nutrient
deficiencies and salinity) that plant breeders have not selected for because
farmers could readily protect the crops from such stresses by generous
applications of water, fertilizers, pesticides, herbicides etc. As a result, our crops
have weakened and now struggle to deliver high yields when environmental
concerns challenge the farmers' continous use of high-input practices. With
established technologies it is feasible to locate the exact mutations that have led
to loss of those functions and with very recent technologies it has become
possible to 'correct' them with precision breeding. In other words, we now have
the opportunity to rewild our crops, so they regain there original strength and
become able to feed the planet's increasing population with minimal
environmental impact. But Palmgren and his colleagues are concerned that
rewilded crops might be doomed - at least in Europe - even before they hit the
soil.
Contrary to conventional genetic engineering - where genes are introduced across
species barriers at random locations along with selective markers and border

2. sequences - the new techniques for precision breeding are, as the name implies,
precise. They specifically break the DNA double strand at exactly defined target
sites in the genome. Subsequently the plant's own repair machinery try to join
the ends again, a process that is often associated with alteration of the genetic
code at the target site and thereby introducing a mutation, insertion or deletion
without leaving any other traces, whatsoever. In crop breeding the technique is
very new and so far has only been used to disrupt gene function. In a recent
study published in Nature Biotechnology in 2014 a team of Chinese
scientists, using a widely used variety of wheat with high yield and other desired
traits but sensitive to the devastating fungus powdery mildew, used precision
breeding to put three allelic variants of a disease gene out of function. With
rewilding it will be possible to restore non-functional resistance genes to the state
of the ancestor without making any other changes to the crop's genome. The new
varieties will contain no alien sequences and since they bear more genetic
resemblance to their ancestors than the varieties they were derived from, one
might argue that they have indeed become even more 'natural'.
In the TIPS paper, Palmgren and his colleagues seek to foresee how rewilded
crops will be perceived by the public and the government. The authors conclude
that in the EU "the techniques used to introduce complete genes or specific
mutations make it impossible for the resulting plants to escape the legal
framework of the GMO Directive, not even if the genes or mutations originate
from wild plants." This is because the EU definition of a GMO is not based on the
nature of the product but instead of the process used to make it. For this reason,
any use of genetic engineering in the process will per definition result in a GMO.
Since the regulatory burden and approval process posses a de facto ban on GMOs
in the EU, rewilded crops might struggle to make it to the supermarket. And if
they eventually get there, they will be branded as GM products. "Studies tell us
that many consumers look with some reservation upon GMO-based products, in
part because they are considered alien. Rewilded crops represent a different path,
yet if branded as GM products may likely face considerable challenges," says
Palmgren.

3. The study has received significant international attention and Palmgren hopes it
will help starting a debate about which products should be considered as GMOs.
He suggests rewilded crops would be less controversial than conventional
genetically engineered plants. And given their huge potential to better utilize
available ressources, to resist diseases, pests and weeds and to have higher
nutritional value they deserve a fair chance for reaching the consumer and help
feed the world.
At University of Copenhagen, Michael Palmgren's own research group - he is a
plant physiologist - is using the new techniques for precision breeding on rice.
They want to recreate the high natural levels of micronutrients that wild rice used
to have and develop more nutritious, rewilded rice varieties that can contribute
in the fight against famine and malnutrition. "The problem is how to get the most
out of our existing agricultural systems without leaving a negative impact on the
environment and the remaining natural ecosystems on earth. Rewilding may
likely form the basis for sustainable agriculture in the future", says Palmgren.
By Gorm Palmgren, science writer, PhD, www.palmgren.dk